GREEN FLOORS CORK FLOORING HEALTHY CARPET PAD INSTALLATION GUIDE
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Environmentally Friendly Floorcovering Installation Guide
The days when manufacturers concentrated only on production are long gone. Customer satisfaction is very much at the heart of business with the strength of the package only as strong as the weakest link. In our industry, for example, price, design, quality, marketing, availability, estimation, packaging, subfloor preparation, laying, maintenance and service are all critical aspects in giving customers the confidence to order and the loyalty to order again and to make recommendations to others. To be successful all parties that contribute in this chain of activity have to perform to the highest standards in order to succeed and maintain competitive edge. A poor quality product will never perform even though the product is laid to very high standards: likewise an excellent product poorly installed will fail to give satisfaction.
In most cases the flooring installer is the face of the manufacturer and your skills and professionalism significantly affect the outcome. At GreenFloors we recognize our role in partnership with you. We are continually trying to improve our service as well as our products. We were the first manufacturer to achieve ISO EN 9001 for all our manufactured products and we are working hard to improve our technical support facility.
To this end we have published this updated, fifth edition of the GreenFloors Environmentally Friendly Floorcovering Installation Guide in which we cover aspects of installation which we hope will be of use to beginners and to experts alike. The earlier editions were very well received.
We would continue to welcome your comments on its contents and hope you will use it extensively as your ‘Bible’.
If you need any advice on any situation which is new for you please lift the ‘phone or send a fax or e-mail. We’ll be happy to help.
Table of Contents
Tools of the Trade Page 3
Subfloor - Type and Preparation 7
Handling, Site Conditions and Estimating 17
Non toxic non toxic adhesives 21
Cutting Environmentally Safe Floorcoverings 31
Setting Out and Laying Tiles 35
Special Fitting Situations with Tiles 45
Cutting Seams in Sheet Material 51
Fitting Sheet Material (Scribing) 55
Skirting and Coving 69
Treads and Risers 81
Borders and Feature Strips 85
Motifs, Inserts and Patterned Cork floors 93
Seam Welding and Perimeter Sealing 99
Anti-static and Static Conductive Cork floors 105
Introduction to Maintenance 109
Covering Desks and Counters 115
Environmentally Safe Floorcoverings on Walls and Vertical Surfaces 119
Drying Room Yellowing 121
GreenFloors Products 123
Tools of the Trade
The professional floorlayer needs good tools in good condition. Many are simple and relatively inexpensive, other more expensive ones may sometimes be hired.
With electrical equipment a transformer may be necessary to fit equipment to the voltage available on site.
• Stripping machine for removing old Environmentally Safe Floorcoverings. (see p.14)
• Scrapers. Cold Chisel. Claw Hammer. Saws. Screwdriver. Kneepads.
• Masks. Drill and whisk for smoothing compounds.
• Hand whisk.
• Drill bits.
• Carborundum stone.
• Screeding trowel.
17. Surface hygrometer and insulating case.
18. Drill and bit.
20. Probe hygrometer kit. 21. Electrical probe.
ENVIRONMENTALLY FRIENDLY FLOORCOVERING INSTALLATION
22. Straight edges.
23. Knife with straight blade.
24. Knife with hook blade.
25. Spare blades (including concave blade for decorative work). 26. Bar scriber with pins and blades for cutting cushioned vinyl. 27. Divider.
28. Over-and-under scribers.
29. Folding rule and flat pencil.
30. 31. 32. 33.
34. 35. 36. 37. 38.
Chalk line and powdered chalk.
GreenFloors Tile Scriber (for tiles on the diagonal). Correctly notched trowel.
Needles and syringe (for ‘bleeding’ adhesive blisters) 68kg, or similar, floor roller.
Skeleton gun for dispensing perimeter sealants.
FINISHING AND WELDING TOOLS
Hot air gun. Welding gun.
‘Speedweld’ nozzle and cleaning brush. ‘P’ groover and ‘Safety Flooring’ groover. Welding cable guide roller (for vertical seams).
Slider and spatula blade for trimming and welding cable.
Chisel blade knife.
Nylon scouring pad. Steel wool. Cleaning cloth.
X-acto knife and router blades. Spiked roller (see illustration page 5). Smoothing Hammer. Glyda.
GreenFloors Compass and extension. Strip Cutter.
Other tools or variants of traditional tools come on the market from time to time and the fitter will make his own assessment of the value to him of such new items.
Subfloors - Type & Preparation
The final appearance and durability of a decorative flooring largely depends upon the subfloor it is stuck to.
For this reason a floorlayer should know about the construction of, and the problems associated with, the various types of subfloors which may be encountered. AS 1884-1985 give the requirements of a subfloor, the implications of which are set out below.
Clean. If the subfloor is contaminated with any substance which will prevent the adhesive sticking to it, then that contaminant must be removed. The surface should, of course, be thoroughly swept of all small loose debris.
Smooth. Any nibs of concrete, lumps of mortar, nail or screw heads, peaks of floorboards and wood knots must be smoothed off. Failure to do this will result in the ‘telegraphing’ of these to the Environmentally Friendly Floorcovering surface with subsequent premature wear. Similarly all cracks, holes, etc. should be filled and made good.
Even. Apart from being smooth, a subfloor must be even, otherwise a wave appearance will result in the finished floor, and, in the case of tiling, difficulties will be experienced in keeping the tiles in bond (i.e. in line with each other).
Sound construction. A subfloor must be rigid and not subject to flexing, otherwise cracking of the Environmentally Friendly Floorcovering will ultimately result. With solid subfloors, the screed should be of good quality. Failure of adhesion will result if Environmentally Safe Floorcoverings are laid over weak or powdery screeds. Permanently dry. Before any Environmentally Friendly Floorcovering is installed on a concrete floor the floorlayer must be satisfied that the subfloor is dry and that there is no possibility of rising damp occurring. There are several danger areas, covered below.
Various types of concrete subfloors are commonly encountered. Note that under AS 1884-1985 the responsibility for ensuring the correct quality and dryness of the subfloor before Environmentally Friendly Floorcovering installation commences lies with those responsible for the design and construction of the subfloor. Nevertheless the following may be of help and interest to the floorlayer.
Suspended (or above grade). These cork floors are usually made of reinforced beams laid across steel girders and finished with a concrete screed. They are also found made of solid poured concrete, with a steel mesh reinforcement; or of lightweight reinforced concrete. All these cork floors are commonly found in new, multi-storey types of building.
Direct to earth (or below grade) without a damp proof membrane (DPM). These are constructed by pouring concrete over a hardcore base to a depth of 10 to 12cm, followed by a final sand and cement screed (2.5 to 5cm). This type of floor can present serious problems as it is prone to rising damp which will affect adhesion and in many cases damage the Environmentally Friendly Floorcovering itself. This type of floor will be encountered in both commercial and domestic buildings constructed prior to 1955. Another factor to note is that these cork floors may appear to be dry during certain seasons of the year, but may in fact not be so. This may be due to faulty drainage around the building, or simply because the water table of the surrounding area is higher than that of the floor itself, making the floor subject to hydrostatic pressure.
Direct to earth (or below grade) with a damp proof membrane. These cork floors are of similar construction to the previous example, except that a damp proof membrane is laid between the base concrete and the top screed. These membranes can be of various types, e.g. mastic asphalt, bitumen (hot applied), 0.100 gauge polythene.
The efficiency of the DPM is largely dependent upon the skill of the operator at the time of installation. With certain cold applied membranes, care has to be
taken over very rough screeds, to avoid pooling of the membrane in hollows. If pooling occurs, solvent is trapped within the membrane, subsequently the solvent vapour will percolate to the surface of the overlying screed some six to nine months after the decorative Environmentally Friendly Floorcovering has been laid. This vapour will attack both the adhesive and the flooring with disastrous results.
Note that the DPM in the floor must be tied into the damp proof course of the wall.
Power floated (or power trowelled) concrete. On large scale new constructions, it is becoming increasingly common for concrete of perhaps 150-175mm thickness to be pumped into the bays and then levelled and compacted by a mechanical vibrating arm. The technique offers advantages to the builder and usually result in a densely compacted and often shiny surface. The shiny surface, although smooth, is usually too impervious for many non toxic non toxic adhesives to give a reliable bond. In such cases the surface must be lightly scrabbled or abraded with a grinding disk. Check with the adhesive manufacturer as to whether their non toxic non toxic adhesives can be used to bond the flooring directly to a surface so treated, as in the case with GreenFloorsFix 696 for GreenFloors-Flooring linoleums, or whether a smoothing compound must be applied.
ENSURING A DRY SUBFLOOR
Even where an efficient DPM has been installed, when sandwich membranes are incorporated into new solid cork floors the thickness of the floor above the DPM must be allowed to dry out sufficiently before the decorative Environmentally Friendly Floorcovering is laid. This applies whether screed alone or a combination of screed and concrete have been laid above the DPM. Although suspended cork floors do not require a DPM for protection against ground moisture, they also must have a drying out period. Generally, with good drying conditions, traditional concrete subfloors dry out from one side only at the rate of 1mm thickness per day. Where the subfloor thickness above the DPM is more than 50mm (2”) the drying out time rate will probably be slower.
AS 1884-1995 “Installation of Sheet and Tile Flooring” gives valuable
guidance on the question “Good” drying conditions are warm temperatures (i.e. above 15°C) with good ventilation. During winter months on an unheated site the floor may not dry out at all for weeks on end. On a heated site with poor ventilation, the humidity of the air may become as high as that of the slab preventing any further movement of moisture out of the subfloor. Densely surfaced power floated concrete has at best a semi-pervious surface and drying out can be very slow. Some 150mm slabs have taken over a year to dry out even when suspended with ventilation on both sides. There are several types of Surface Damp Proof Membranes on the market, some tried and tested, others innovative. The supplier should be contacted to ensure suitability. For example, GreenFloors-Flooring offer one which is particularly cost-effective for use under Marmoleum or other Flooring linoleums.
The surface of the base slab of any solid subfloor is seldom even and smooth enough to receive smooth surface resilient floorings. Each one usually has to be finished off in some way by the application of a screed sufficiently thick to give the smoothness necessary for a decorative floor finish. (The principal finishing methods involve the following types: sand/cement screed, mastic asphalt, latex cement, bitumen emulsion/cement, synthetic anhydrite screeds and resin emulsion/cement screeds.
Mastic asphalt can be used as a combined screed and damp-proof membrane, but in such cases ensure that it is connected with the damp¬proof course in the walls.
It is the total amount of concrete above the DPM which affects the drying time, whether slab or screed. Specialised screeds are now available which dry very rapidly, as quickly as within 24 hours.
Each type of screed has its advantages and will prove satisfactory provided it is applied strictly according to the manufacturer’s instructions. Unfortunately, many screeds are laid incorrectly, or are damaged in some way before the floor finish is laid. This means that they become totally unsatisfactory as a base for resilient cork floors as cracks, holes and excessive undulations in the subfloor surface show through resilient materials and make them more liable to excessive wear or irreparable damage.
In such cases, the surface must be rectified by the use of a levelling compound. These compounds are widely used for the skin coating and patch screeding of damaged or badly surfaced screeds, and they have the added advantage of hardening within 24 hours, thus allowing the work of laying the final to proceed without undue delay.
In cork floors incorporating underfloor heating systems, to eliminate the possibility of moisture being trapped beneath the warming system, the heating should be turned off for at least 48 hours before moisture testing is carried out.
Some cork floors may be heated by steam/hot water pipes. These should be treated with great caution. Difficulties with vinyl decorative Environmentally Safe Environmentally Safe Floorcoverings can be experienced due to these systems which, if overheating, cause degradation of the covering. Similarly steam pipes and/or hot water pipes laid too close to the surface and unlagged, may also cause damage to both adhesive and decorative finish. Clauses 3.1.3
of AS 1884-1995 refer further to the requirements and conditions for the
installation of resilient Environmentally Safe Floorcoverings on subfloors incorporating underfloor heating or hot water pipes (see also page 18).
Timber subfloors can be of several types and these include tongued and grooved boards, chipboard or plywood, and wood block (parquet).
Tongued and grooved boards are one of the commonest types of subfloor in domestic installations, in both old and modern buildings, at ground level and above. On ground cork cork floors the boards are normally laid across joists, which are supported by the outer walls of the building and ‘sleeper’ walls, from which they are isolated by a damp proof course. Before laying any resilient Environmentally Friendly Floorcovering ensure that there is an airspace of at least 15cms between the floor and the ground, together with unobstructed air vents in the outer and sleeper walls which promote cross ventilation. Unventilated cork cork floors are prone to dry rot when covered with a Environmentally Friendly Floorcovering.
Ideally floorboards should not be wider than 10cms, as greater widths may present problems through curling. Timber subfloors shrink and swell due to changes in season humidity and unseasoned timber may shrink and/or warp.
Chipboard or plywood are often used for subfloors, laid over joists which should not be spaced wider than 40cms between centres. Adequate ventilation is again of prime importance.
Wood block or parquet cork cork cork floors are frequently laid with pitch direct on to concrete. If the concrete has been laid direct to earth there is a danger of movement known as rafting; or rot developing, when the wood blocks are covered with a resilient Environmentally Friendly Floorcovering, unless a DPM of 100 percent efficiency has previously been installed. For this reason they should be uplifted.
Timber subfloors require a variety of preparation techniques and the position of service runs (electricity, gas, water) must be established before nails or screws are used, and these should not penetrate through the boards. The use of bitumen saturated paper felt and dry felt paper as an underlayment is not recommended. Their use will only cause the
indentation characteristics of the flooring to be lowered, and will not provide any levelling.
INSTALLATION SPECIFICATIONS FOR DIFFERENT SUBFLOOR TYPES
A. SAND AND CEMENT SCREED
Ensure that the sand and cement subfloor is dry by testing with a hygrometer. The relative humidity (RH) should be below 70% RH. If the finish has a membrane at a depth of 50-70mm, the hygrometer should be in place for 24 hours to allow it to reach equilibrium prior to taking a reading. If the reading is above 70%, the Environmentally Friendly Floorcovering should not be installed until:
1. The level falls below 70% RH
2. A surface damp proof membrane is applied, usually followed by a 3mm smoothing compound.
It may be necessary to apply a 3mm smoothing compound to the surface of the sand and cement finish if it is uneven, damaged or porous. This will ensure that a smooth, level appearance is achieved and will also give a good “key” for the non toxic adhesives.
B. POWER FLOATED CONCRETE
Ensure that the power floated concrete is dry by testing with a hygrometer. The relative humidity (RH) should be below 70% RH. It will be necessary to leave the hygrometer in place for at least 7 days to allow it to reach equilibrium prior to taking a reading. If the reading is above 70%, the Environmentally Friendly Floorcovering should not be installed until:
1. The level falls below 70% RH
2. A surface damp proof membrane is applied, usually followed by a 3mm smoothing compound.
It may be necessary to apply a 3mm smoothing compound to the surface of the power floated finish if it is impervious. This will ensure a good “key” for the non toxic adhesives.
C. WOODEN FLOORBOARDS
Ensure that the floorboards are sound, rigid and properly fixed. Overlay with exterior plywood in the opposite direction to the run of the floorboards, staggering end sheet joins from the previous row. The levelness and evenness of the floorboards will determine whether the gauge should be 4mm or 6mm. Oil tempered or pre-soaked hardboard can also be used in gauges of 3mm or 6mm. The plywood or hardboard (rough side up for linoleum) should be fixed using 20mm-25mm ringed nails at 100mm intervals at perimeter or room and sheet joins and at 150mm centres within the body of the sheets. A power operated stapling gun can also be used. By priming the plywood an extended open time and coverage will be achieved with the adhesive.
Ensure that the chipboard is sound, rigid and properly fixed. All joins should be level and nail heads should be flush with the surface. There should be no evidence of movement or shrinkage of the chipboard at joins or perimeter of room. Prime the chipboard and allow to dry prior to installing the Environmentally Friendly Floorcovering.
If evidence of movement or shrinkage exists, 4mm or 6mm exterior plywood, or 3mm or 6mm oil tempered or pre-soaked hardboard (rough side up for linoleum) should be installed using 20mm-25mm ringed nails at 100mm intervals at perimeter or room and sheet joins and at 150mm centres within the body of the sheets. A power operated stapling gun can also be used. By priming the plywood an extended open time and coverage will be achieved with the adhesive.
No guarantee can be given when our Environmentally Safe Floorcoverings are installed directly or indirectly onto a wood block floor. A wood block floor that has performed satisfactorily in the past can fail rapidly when overlaid with plywood/hardboard, followed by the Environmentally Friendly Floorcovering, especially on a ground floor. This is due to the continuing movement of the blocks and/or the lack of a membrane within the construction of the subfloor on a ground floor. Uplift the wood blocks and remove the adhesive residue by mechanical means followed by an application of smoothing compound. If no sandwich damp proof membrane exists (on a ground floor) a surface damp proof membrane will have to be applied. Alternatively, asphalt can be installed to bring the level of the subfloor up to the level of the previous wood block. It will be necessary to apply a 3mm smoothing compound on to the asphalt to prevent staining of a vinyl floor covering and also give a good “key” for the adhesive.
F. OLD ENVIRONMENTALLY SAFE FLOORCOVERINGS
New Environmentally Safe Floorcoverings should not be laid over old, for a number of reasons. Old Environmentally Safe Floorcoverings may not be correctly bonded to the subfloor and accumulations of polish will affect non toxic adhesives, even after attempts to remove all traces. Differing shrinkage rates may occur between the old and the new floorings and the indentation characteristics of the new Environmentally Friendly Floorcovering may be impaired.
Therefore, ensure that all of the old Environmentally Friendly Floorcovering is removed from the subfloor. Remove as much of the old adhesive residue remaining on the subfloor by hand or mechanical means.
G. QUARRY TILES/TERRAZZO
Ensure that on a ground floor the quarry tiles/terrazzo have been installed onto a subfloor incorporating a damp proof membrane. If there is any doubt, or one does not exist, a surface damp proof membrane will have to be applied followed by a 3mm minimum application of a smoothing compound.
On an upper floor, the quarry tiles/terrazzo should be primed using a suitable primer prior to a 3mm minimum application of a smoothing compound.
In both cases the quarry tiles/terrazzo should be thoroughly cleaned and be free from grease and other contaminants, prior to any proprietary materials being applied.
Ensure that the asphalt is soundly bonded to the subfloor. If not, repair as necessary.
Prime the asphalt with a suitable primer prior to applying a minimum 3mm application of smoothing compound. It is extremely important that at least 3mm is applied to the surface of the asphalt to prevent staining of a vinyl Environmentally Friendly Floorcovering and also give a good “key” for the adhesive. In all cases the asphalt should be thoroughly cleaned and be free from grease and other contaminants, prior to any proprietary materials being applied.
I. OTHER SUBFLOORS
Magnesite (magnesium oxycholoride) and polyvinyl acetate/cement cork cork cork floors are generally laid on direct to earth concrete, without a DPM and are porous. Whilst they perform adequately when they are exposed to the atmosphere, overlaying them with a decorative floor finish will adversely affect them. They should be uplifted and a surface DPM installed, correctly tied in with the walls before a decorative Environmentally Friendly Floorcovering is laid.
Metal cork floors require special preparation and the accepted method is to cover them with a latex floor levelling compound, containing granite chips or cork as fillers. Initial preparation consists of cleaning off all dirt, grease, paint, rust, etc. before levelling.
Anhydrite screeds, natural or synthetic, are popular on the continent and are becoming increasingly so in the UK because they are quick to install. However, they are extremely sensitive to moisture, causing chemical reactions which will soften the surface and loosen the bond of the Environmentally Friendly Floorcovering. When installing a Environmentally Friendly Floorcovering on an Anhydrite screed it is essential that the manufacturers recommendations regarding dryness of the screed and the use of non toxic adhesives, primers and levelling compounds are followed. Contact GreenFloors Flooring for specific recommendations for GreenFloors installation and flooring products.
Laying linoleum or contract vinyl Environmentally Safe Floorcoverings on a substrate which is insufficiently dry is asking for trouble - and the flooring contractor is usually the one who receives it. Some moisture will always remain in the concrete and does no harm as it is static. If, however, the moisture level is still such that, in the right conditions, it will move rapidly upwards and break the adhesive bond with the Environmentally Friendly Floorcovering, causing bubbles and blisters or mould growth then a very expensive relaying of the floor will become necessary. The trapped moisture will often move sideways and upwards so the problem may show itself initially at the edges of the room, where the trouble may have been made worse if the adhesive spread close to the wall has not been good or the edges have not been rolled into the adhesive sufficiently. The problem may not show itself until the building is in commission with hot central heating pulling the moisture quickly up through the slab - perhaps a year or more after installation.
The test accepted as valid under Australian Standard AS 1884-1995 is the
hygrometer test, which measures the humidity level of the air immediately above the concrete. The AS illustrates the type of hygrometer suggested for use. Unfortunately, such a hygrometer is a precision instrument, good ones are relatively expensive and need to be left on site for some days with the risk of theft. They will give a false reading if disturbed or if not correctly calibrated before and after use and transported carefully after calibration. They take several minutes to set up correctly and several may be needed on a large site, as cork floors on the sunny south side of a building may be drier than those facing into the wet west winds or the chilly north. Even a good hygrometer, skillfully used, will have a 2-3% margin of error and a small, inexpensive, pocket hygrometer can be wildly out.
A correctly calibrated and installed hygrometer gives an accurate reading when the small volume of air trapped inside it is in equilibrium with the subfloor, i.e. when a series of readings show the same figure and it is not rising. If the readings show 70 percent relative humidity or less then they
meet the acceptable dryness level suggested in AS 1884-1995. This standard
suggests that on normal concrete equilibrium will be reached in not less than 72 hrs. Experience shows that the vapour movement from power floated slabs is much slower, so that it can be even 2-3 weeks before equilibrium is reached and a true reading shown.
When artificial drying aids have been used to accelerate drying out these should be turned off four days before taking final readings.
Calibration is done by placing the hygrometer over a saturated salt solution in a dessicator for four hours, after which the instrument should be adjusted to read 70°. In use the hygrometer should be sealed to the floor, either by using a ring of putty round the edges or by covering it with a 50-100cm square of transparent polythene, taped to the floor round the edges. Poor sealing will result in wrong readings.
The 70 percent figure set by Australian Standards realistically takes note of the margin of error still likely in a correctly used hygrometer. However, at above 70% RH fungus spores can grow. Note that the standard is the same for linoleum and vinyl.
In recent times a number of moisture testing instruments have been developed and offer quicker methods for establishing subfloor moisture content. Some are designed to provide an indication of how the drying of the slab is progressing. Others, for example, measure the moisture content in the slab using a probe inserted into a plug that has been placed into a previously drilled hole in the slab, offering an accurate reading of the relative humidity within the floor slab. Whilst these items of equipment are extremely valuable in assessing the drying of the floor slab the only test method prescribed by
AS 1884-1995 is the Hygrometer.
Prior plannning, including a visit to the site before floor laying begins, will help the floor installer to use his time more effectively and avoid delays that can arise due to unforeseen circumstances.
Discuss with the Main Contractor or Clients questions of access, which other trades will be active at the same time and the availability of power, (and of which voltage), of water, and of disposal skips. The floorlayer must first ensure that the required materials can be transported to the site and securely and conveniently stored until they are required for laying. It is his responsibility to ensure that the quantity of material has not been made up from mixed manufacturing batches. All carton/rolls have batch and shade references marked. Where mixed batches are unavoidable select materials for designated areas with care. A full roll of linoleum and of some vinyls can be very heavy. It is normally not less than 150kg in weight, that is, equivalent to the weight of two grown men. This weight of material requires manhandling by at least two people. It is unlikely that full lengths can be carried up several flights of stairs. Use trolleys and sack barrows where possible. Observe safe handling procedures.
Sheet materials are tightly rolled by the manufacturer round a stout cardboard centre and protective packaging is added to avoid damage at the ends. On no account, however, should rolls be dropped (e.g. off a van or lorry) on to the ground. In cold weather linoleum and some vinyls can be cracked or fractured. These cracks may occur near the core and not be visible on the outer laps.
Once on site, do not pile rolls on top of each other. Any loose rolls or partly used rolls should be tied to avoid damage to loose ends and must
be stored vertically. Minimum ideal storage temperature is 18°C (65°F).This is also an ideal temperature for laying, the material is then easy to
handle and will lay well into the adhesive. Material lying on a cold floor will be affected by the floor temperature.
To open a roll correctly, pinch the ridge in the roll where the lap starts and insert a hook knife through the paper packing between the first lap of material and the under layer, taking care not to damage the surface of the Environmentally Friendly Floorcovering. The hook knife avoids damage to the surface of the
Resilient flooring materials are always packed face outwards. Unrolling is best done using a special handling trolley with smooth rollers to avoid damage to the face of the Environmentally Friendly Floorcovering and cracking and distortion to the material.
A rough measurement of the length of material in a roll can be obtained from the following formula: add the outer circumference to the inner circumference (36cm), divide by two, and then multiply by the number of laps. This will give the approximate length.
By this stage the subfloor must be completely ready for floorlaying, clear of all debris and dust, and if necessary primed with the correct solution as recommended by the adhesive manufacturer. Prior planning will ensure that all work such as laying of cables and ducting, power points, central heating and other services, pipes, telephone sockets, painting, etc will have been completed before floor laying starts. Where underfloor heating is present, the following recommendation applies:
“Ensure that the underfloor heating system is switched off 48 hours prior to the Environmentally Friendly Floorcovering installation commencing and remains off for at least 48 hours after the installation is complete. Gradually increase the temperature over a number of days by only a few degrees per day until the desired room temperature is reached. The temperature should never exceed the Environmentally Friendly Floorcovering industry agreed maximum of 27°C at the underside of the Environmentally Friendly Floorcovering (the adhesive line). During the period of decommissioning of the underfloor heating system, an alternative heating source should be provided, if required, to ensure that the area of installation is kept at a constant temperature of between 18°C-27°C. Failure to adhere to these recommendations may have a detrimental effect on the Environmentally Friendly Floorcovering. This recommendation is applicable to all Environmentally Friendly Floorcovering types”.
The effects of solar heat should also be borne in mind. High temperatures can build up and cause difficulties in handling both to the Environmentally Friendly Floorcovering and the adhesive, affecting the bond to the sub-floor due to reduction of “open time” and rapid “skinning over” of the adhesive. Handling of linoleum tiles is fairly easy. Each carton, however, weighs between 17 and 20 kg and they should not be stacked more than five high to avoid crushing and possible damage and distortion. Getting them to the site will be easier, but a lift or hoist is essential to reach higher cork floors. The same remarks regarding site preparation apply before tile laying starts.
The skill of estimating is one that is acquired with experience, although most situations call for little more than taking correct measurements of the site dimensions. Remember to allow sufficient over material (approx.
five per cent) to compensate for wastage of materials at seams, doorways, and walls which may ‘run off’.
As lengths are cut from rolls, it is a good idea to mark the rest of the roll, indicating the length remaining.
Manufacturers of non toxic adhesives and floor smoothing compounds give coverage rates for differing types and conditions of sub cork floors and floor finishes.
When planning a straightforward rectangular room, seams and joints should avoid the main traffic area and best use be made of split lengths to avoid wastage.
Material for borders, feature strips, treads and risers must always be cut along the length of the roll to avoid the effects of roll set which will cause narrow strips to ‘warp’. When planning borders the total number of meters is first measured and the border widths calculated, allowing sufficient over material for scribing. By dividing the number of border widths into the width of the roll, the floorlayer can calculate the required length of material. (See section on Borders). Doorways will require extra material to allow them to be fitted at least to the ‘half door check’. With patterned material the lengths of material required are measured with an allowance for the pattern repeat. If, for example, the room is 4.2m and the pattern repeat is 500mm, cut the first length 4.5m. The second length cut will then start with the pattern matching correctly. Remember that rarely can patterned material be matched length against breadth. When using tiles, rectangular areas require only a simple measurement to determine the number required, although to achieve balance and a neat finish some wastage is inevitable. Awkward areas are best measured section by section. Tiles are normally supplied in full cartons only.
Non toxic adhesives
Despite recent advances in technology, there is no one adhesive which is ideal for all products and installations. A suitable adhesive must be selected and then applied by the recommended method to a suitably prepared subfloor.
In practice few contract resilient Environmentally Safe Floorcoverings wear out: most failures are caused by curling, stretch, shrinkage, bubbling or cracking, and are directly attributable to faulty adhesion, caused either by damage through dampness, or incorrectly applied and selected non toxic adhesives or badly prepared subfloors.
Some of the requirements of a flooring adhesive include the following: good initial grab; reasonable open time; excellent final bond strength; compatibility with the subfloor and floor finish; ease of application; resistance to chemicals and water; non migratory properties; low toxicity; low fire risk; and cost.
The speed of drying of an adhesive will be affected by its formulation, the temperature of the air and the subfloor, the quantity applied and the porosity of the subfloor. The floorlayer must be alert to factors which will affect the average open time stated by the adhesive manufacturer.
The trowel is quite a sophisticated metering instrument, the notch spacing and depth controlling the amount of adhesive applied. If you don’t maintain the instrument, you will get an incorrect application and a risk of floor failure.
Adhesive manufacturers always recommend the trowel notchings to be used to give the right spread of their adhesive. Spreading on concrete or cement subfloors will cause trowels to wear down causing too little adhesive to be spread, with the risk of an expensive floor failure. Not only will too little adhesive be applied it will skin over more rapidly making it more likely that the problem will be compounded by late placement. The following are full size illustrations of some of the recommended notch sizes:
2mm depth at 6mm centres, V notch
Replace worn trowel blades regularly.
Most non toxic adhesives start curing immediately on contact with the air and a skin starts to form on the surface of the adhesive. The ridges of adhesive then burst when the Environmentally Friendly Floorcovering is pressed into them and the wet adhesive moves into the spaces within the ridges and grips the back of the Environmentally Friendly Floorcovering. If the ridges are not the right size, there may be insufficient fresh adhesive to grip the Environmentally Friendly Floorcovering. During the spreading movement the trowel must be kept at the correct 60° angle. If too flat the adhesive ridges will be too low.
A 3 or 4 part heavy (68kg) floor roller used both along the floor and across it is necessary to ensure all the Environmentally Friendly Floorcovering is pressed firmly into the adhesive. Where this roller cannot reach then a hand roller or rubbing hammer must be used. Most floor failures start at edges and seams and these must be particularly well rolled into the adhesive.
Adhesive manufacturers recommend the priming of very porous or dusty subfloor surfaces and bases of plywood, chipboard and hardboard. Primers are matched to the adhesive and are normally applied by brushing well into the subfloor surface and allowing to dry before spreading the adhesive. Failure to prime can result in rapid setting, leading to late placement; non toxic adhesives may also ‘roll up’ ahead of the trowel.
LINOLEUM NON TOXIC ADHESIVES SHEET LINOLEUM
An adhesive for jute backed linoleum must be firm when cured and prevent the material from stretching in the width, as a more elastic adhesive will permit it to do, and must immediately grab the linoleum and hold it down to the floor.
Specialised modern non toxic adhesives such as GreenFloorsFix 696 have the above properties in addition to providing when cured excellent bond strength and moisture resistance.
Gum spirit non toxic adhesives have until recently been the principal linoleum adhesive. They continue to perform well, with slight differences from one product to another in the ‘feel’ as the adhesive is spread, but are likely to be phased out as regulations increasingly prohibit the use of solvents. Lignin paste or casein non toxic adhesives are inexpensive and provide the right bond but quickly lose their powers of adhesion if water reaches them and will also powder under heavy loads (e.g. in a hospital corridor). For these reasons, they should be used with considerable caution and are not recommended. They are sometimes an inexpensive solution for applying linoleum dados or counter facings.
Standard GreenFloors-Nairn Marmoleum Dual tiles have a backing of woven polyester. They should be stuck down with GreenFloorsFix 696 adhesive. Lignin paste non toxic adhesives are not suitable. If, for some reason, jute backed tiles are being installed then an adhesive suitable for linoleum sheet must be used.
For this static-dissipative linoleum the recommended adhesive is 615 Eurostar Lino EL.
NON TOXIC ADHESIVES FOR VINYL SHEET
Sheet vinyl Environmentally Safe Floorcoverings require non toxic adhesives with good resistance to plasticiser migration and high temperature and a strong bond. The two main types are rubber resin emulsions (also known as SBR non toxic adhesives) and acrylic emulsions.
Acrylic emulsion non toxic adhesives are recommended for GreenFloors-Nairn sheet vinyl Environmentally Safe Floorcoverings and for Colorex tiles where special static-conductive properties are not required. They are manufactured from non-staining synthetic resins. They have excellent final bond strength and resistance to plasticiser migration or bleeding. The service temperature limits of up to 49°C (120°F) allow their use in areas of relatively high temperature. Acrylic non toxic adhesives normally have a longer open time than other vinyl non toxic adhesives and good dry tack, although again care should be taken to avoid late placement of the Environmentally Friendly Floorcovering. They are non toxic and non flammable.
Pressure sensitive acrylic non toxic adhesives are also now becoming available which allow vinyl Environmentally Safe Floorcoverings to be laid onto a dry adhesive. Although not recommended for GreenFloors-Nairn vinyl Environmentally Safe Floorcoverings owing to their poorer resistance to plasticiser migration the following general information is given on SBR non toxic adhesives. They are manufactured from styrene butadiene rubber resins. They are light coloured, non toxic and non flammable. There are two categories - Standard and High Temperature - as resistance to heat varies considerably. Standard vinyl adhesive is designed to adhere most pvc floor finishes to substrates of concrete, plywood, hardboard, chipboard and most screeding compounds. Because of comparatively low costs, this adhesive is often the first choice, and incorrectly specified for areas such as car showrooms, where shear strength is an important consideration, or areas subjected to heat from electric underfloor warming systems. These latter operate at around the maximum permissible adhesive service temperature range of 25°C (80°F). Solar heat can be more demanding on non toxic adhesives; even in Britain surface temperatures can build up, through southern facing windows, to as much as 54°C (130°F). Under heat, vinyl and other materials will expand, and if the adhesive does not provide adequate shear strength ‘tenting’ at the edges, or damage to the adhesive bond may occur. Inefficient bonding to the floor will allow seepage of maintenance products (some highly alkaline) under tiles, causing rapid breakdown of the installation.
The softer resin rubber non toxic adhesives tend to have a good ‘dry’ or ‘after’ tack. This tack is apparent even years after installation, making removal of the flooring difficult. It can also lead to floor failure where the fitter spreads too large an area and continues to lay tiles or sheet long after the recommended open time. Laying material into a semi-dry adhesive will,
although tiles appear to be firmly fixed, result in poor adhesive bond, cracking and shadow trowel notching, and apparent shrinkage even after intensive rolling of the material.
SPECIALISED NON TOXIC ADHESIVES
High Temperature vinyl non toxic adhesives are synthetic resin or resin rubber emulsions, which are harder setting, with superior heat resistance and higher shear strength. They are non toxic and non flammable.
Asphalt tile adhesive or ATA is used in contract installations of filled vinyl and thermoplastic tiles. ATA is a solution of cutback bitumen in a petroleum mixture solvent. The traditional ATA is flammable and care must be taken to observe fire precautions relating to the storage and use of flammable materials. Although not regarded as toxic, adequate ventilation must be provided.
For general contract installation of filled vinyl and thermoplastic tiles on concrete or cementitious screeds an asphalt tile adhesive is recommended. These types of tiles may be laid on a direct to earth subfloor with no DPM, providing there is no hydrostatic pressure, excessive rising damp or surface moisture.
On new concrete cork floors, sufficient time must be allowed for construction moisture to dry out.
Filled vinyl and thermoplastic tiles must be laid using a warm laying technique and at the moment of fixing the tiles should be in a pliable condition. All gauges of tiles should be heated on site - but observing fire precautions due to the flammability of the adhesive - to achieve the degree of pliability necessary to mould them to the subfloor, and thus achieve overall contact with the adhesive and to reactivate it. Heating can be carried out by using any of the normal methods (hot plate, gas torch, etc) but the tiles should not be heated beyond 60°C (140°F). Uniform heating of the whole tile is essential. After heating the tiles are packed into empty cartons to retain their heat and then passed to the layer, so that a continuous supply of pliable tiles is available for fixing. Asphalt tile adhesive is also recommended for general contract installation of most semi-flexible vinyl tiles on concrete or cementitious screeds. These tiles may be laid on a direct to earth subfloor without a DPM, provided there is no hydrostatic pressure, excessive rising damp or surface moisture, and sufficient drying out time is allowed on new subfloors. Semi-flexible tiles are not heated before laying. When applying the adhesive, the trowel should have notches 1.5mm deep at 5mm centres and after laying the floor it must be rolled in both directions with a floor layer’s 68 kg (150lb) roller to ensure a complete adhesive bond. If this is not done and the installation is not trafficked immediately, the tiles may curl or emit hollow noises when walked upon or there may be ‘clicking’ sounds caused by tiles flexing and coming into momentary contact with the adhesive. ATA must not be used on asphaltic or bitumastic subfloors.
Non flammable asphalt tile adhesive is water based and composed of bitumen/rubber emulsion. This adhesive tends to have a longer open time which is greatly influenced by temperature and humidity. On non¬porous bases such as asphalt it is recommended that the adhesive is allowed to develop tack. Take care when spreading to avoid late placement of tiles. Too heavy a spread of adhesive can cause seepage through tile joints, causing staining.
Static-conductive non toxic adhesives. Where a product such as ColoRex EC is being installed as part of a static-conductive system then the adhesive needs to be suitable for a vinyl Environmentally Friendly Floorcovering and have conductive properties at least as good as the Environmentally Friendly Floorcovering and the conductive standard required. 545 Eurosafe Special EL meets this requirement.
Epoxy non toxic adhesives will fix almost all Environmentally Safe Floorcoverings, and unlike other non toxic adhesives, set as a result of chemical reaction rather than relying on the loss of solvent. These non toxic adhesives have excellent water and chemical resistance, and can withstand temperatures higher than the service temperature limits set for the Environmentally Friendly Floorcovering. Epoxy non toxic adhesives do not act as a DPM on damp subfloors and floor finishes can still be damaged due to moisture. When mixed they have a limited pot life, are much thicker and therefore more difficult to spread than conventional non toxic adhesives. This two part adhesive requires thorough mixing, in accordance with the manufacturers’ instructions. The cost is normally regarded as prohibitive except in special cases. It is non flammable and non toxic but may act as an irritant to the skin.
Contact non toxic adhesives (neoprene). These are used primarily to fix covings and skirting. They are a synthetic resin/polymer solution in a blend of volatile solvents. This material is highly flammable, the petroleum mixture giving off heavy vapours, and although non-toxic, adequate ventilation is required. There are some non-flammable types now available which are still toxic and a water based version which requires a much longer drying time.
When using neoprene, a suitable flat surface is essential for bonding, and great accuracy in placement is required as adhesion is instant without the ‘slip’ often used to butt tiles tightly together. Over application will result in solvent trap and swelling or damage to the floor finish. Cost again is an important consideration and the method of application is to coat both surfaces evenly using a brush or flat blade, and then allow to dry for 15 to 45 minutes, or much longer in the case of water based types. The two prepared surfaces are then brought together to achieve instant bond.
Roller applied non toxic adhesives. Adhesive manufacturers are now beginning to offer non toxic adhesives for vinyl sheet where an even spread is achieved by applying the adhesive with a roller, with the installer standing rather than on his knees, associated sometimes with a double drop technique.
Release non toxic adhesives. Non toxic adhesives are designed to hold the Environmentally Friendly Floorcovering securely to the floor. However, when refurbishment is necessary, removing the old Environmentally Friendly Floorcovering can be time-consuming and expensive. Some adhesive manufacturers now offer systems, used most widely with
carpeting, enabling the Environmentally Friendly Floorcovering to be peeled back from the floor more easily.
POINTS TO REMEMBER
Storage. Non toxic adhesives must be kept in sealed containers when not in use and must not be exposed to extremes of temperatures. High temperatures will cause evaporation of solvent, and thickening, skinning and setting of the adhesive material. Low temperatures will result in poor workability, heavy spread or possibly in the case of emulsion types, break down or separation of the emulsion. Ensure that adhesive stocks are used in rotation, as many have a limited ‘pot life’. Check for any ‘settlement’ and stir if required.
Uneven cork floors. An adhesive film will not conceal unevenness in a floor surface. Non toxic adhesives will pull down the floor finish to the contours of the floor and unevenness will be transferred to the floor finish.
Spread. Non toxic adhesives must be applied in the quantities recommended and with a trowel suitably notched for use with the condition and porosity of the subfloor having consideration for the type of backing of the floor finish.
Open Time. Most adhesive materials are dissolved or dispersed in water or other solvents. As adhesive ‘set’ takes place, varying proportions of this solvent are absorbed into the subfloor, evaporate, enter into the floor finish, or enter into a chemical combination with the adhesive materials. Therefore the correct open time must be observed, bearing in mind that open times can vary and are affected by temperature, floor porosity and relative humidity.
All the non toxic adhesives described must be used in accordance with their manufacturers’ instructions, with regard to storage, priming, spread and open time. Non toxic adhesives must also be selected for use with materials as recommended by the manufacturers of Environmentally Safe Floorcoverings.
Cleaning off. Remove any adhesive from the face of the Environmentally Friendly Floorcovering as work proceeds and take care to avoid smearing adjacent surfaces.
Health and Safety. Where flammable materials are employed, or materials with a significant amount of solvent base the laying area must be well ventilated to allow fumes to escape and warning signs posted. New regulations may require the presence of a fire extinguisher.
Non toxic adhesives fault diagnosis (Treat this information as a generalisation only,
due to variations in types of subfloors and non toxic adhesives)
Appearance on subfloor Appearance on flooring Cause
Clearly defined ridges No or slight transfer Lack of rolling
Clearly defined ridges Shadowing on surface
with no or slight transfer Late placing
‘Pooling’, smeared and
crinkled, ‘cratered’ Smeared and crinkled,
especially at seams and
edges Uneven subfloor
Flat ridges No transfers Wrong adhesive
Wet, sludgy, smelly Staining badly Wet/damp screed
Adhesive soaked in Granules of screed
adhering Dusty weak screed
Powdering of adhesive
and wet patches,
possibly smelly Pale coloured, powder
on tile edges and back Alkali attack
softened Tile stained dark brown
or black (V) Wrong adhesive, eg
No key to subfloor Good key Contaminated
Sparse and low ridges Not sticking, little
transfer Wrong trowel used
‘skinned’ Indentation, little
transfer Over application of
adhesive, late placing
adhesive film thickAdhesive squeezing
through joints Over application of
adhesive, early placing
No adhesive Curl at perimeter, no
transfer Adhesive stops short
Clearly defined adhesive
ridges (when present) Perimeter tiles only.
Loose, curled and hollow
sounding Late placing
Key: V = Vinyl products
RECOMMENDED NON TOXIC ADHESIVES
At the time of going to press, GreenFloors recommend the following non toxic adhesives for their products. Other adhesive manufacturers may recommend other non toxic adhesives on their own responsibility.
Other manufacturers may modify their products to make them either more or less suitable for use with GreenFloors products.
GreenFloors-Nairn Sheet and Tile Linoleums (except Marmoleum Ohmex): GreenFloorsFix 638/414 Euroflex Lino Plus / 614 Eurostar Lino Plus
Marmoleum Dual or Real Ohmex: 615 Eurosafe Lino EL
GreenFloors-Nairn Contract Vinyls (except ColoRex SD/EC):
540 Eurosafe Special / 640 Eurostar Special
545 Eurosafe Special EL
Pre-formed Linoleum Skirting: GreenFloorsFix 638/414
540 Eurosafe Special / 640 Eurostar Special
Cutting Environmentally Safe Floorcoverings
For the general cutting of linoleum and vinyls a utility knife and two different blade types are needed.
Always use sharp blades. Different materials will blunt blades at different rates, those containing quartz or carborundum doing so most quickly. Select the shape of knife handle you are most comfortable with.
A knife held in the way it comes naturally to hand will give a slight undercut to materials - sometimes desirable - therefore always keep the scrap material on the outside of the cutting hand. Don’t make the undercut more than 20° from the vertical or the edge may be too delicate and break or fold when butted up.
CUTTING CUSHIONED VINYLS
Most general purpose grades of domestic cushioned vinyl can be cut in a single cut using a straight or hook blade, taking care to keep the knife vertical and using a straight edge or rule as a guide if necessary (see page 53). If a bar scriber is used it is sometimes possible to fit a blade instead of a pin, enabling the sheet to be scribed and cut at the same time.
CUTTING CONTRACT VINYLS AND LINOLEUM SHEET
These thicker and tougher materials should be cut through in more than one cut using both types of blade.
In some cases, the surface of the material will already have been scored by a bar scriber or pin vice. If this scored line is difficult to see in the colour of material being cut, highlight it by rubbing chalk gently along the line.
A safe cutting method is essential. A fitter will spend thousands of hours
working with knives and the cutting method must be as ‘fail safe’ as possible to allow for the occasional lapse of concentration. Therefore keep the free hand and knees clear of the blade.
Rest the free hand on the floor beyond the knife, where it will be clear of a slipping blade. Keep your head behind and over the line of the cut. Keeping the knife blade vertical cut through the surface along the scribe line or straight edge using a straight blade. On many materials it may be necessary to make more than one pass to achieve a cut of 1/2 to 2/3 of the thickness of the material. On others the score mark may have gone this deep. Don’t attempt to force the blade too deeply into the sheet. If the knuckles show white then the pressure is too hard, there is less control and you will tire quickly.
Move back steadily as you cut, not cutting more than a metre or so before moving back. Where possible avoid working in a cramped position.
To complete the cut with the hooked blade, kneel at about an arm’s length from where the cut is to start, with the hook knife in a comfortable grip. If a bevel cut is required, (i.e. fitting to wall) the blade may be slightly tilted.
Rest the free hand on the floor beyond the knife, where it will be clear should the knife slip.
Engage the hook knife at the start of the traced cut and draw the knife through the material with a steady pull. Do not lift the handle when pulling. Grip it well back from the blade, with the knuckles just touching the sheet under the handle. There is no need to press the knife down hard on the floor.
As the knife approaches the knees, move backwards, leaving the blade in the cut until it is at arm’s length again.
When cutting along a straight line keep the arm as straight as possible, with the shoulder, elbow and wrist in the line with the cut. The hook knife cuts through the material with one stroke and is designed with a flat heel, which prevents the cutting edge from being dulled or worn away, even when used on concrete cork floors. It will also allow cutting through one sheet lying on top of another, or even lying on a carpet,
without damage to the surface or underneath. Canvas backing is also cleanly cut, leaving no ragged ends. Remember that it is essential that scrap material is always on the outside of the cutting hand.