Corka Plank Installation
Our Corka Plank is easy to install and many of our customers choose to do so themselves as a DIY project, but if you are looking for an experienced fitter, we can help – just email us your postcode. We have a list of fitters recommended by our customers and who we have found to be reliable – though please note these are independent tradespeople and as such we cannot take responsibility for their work or any arrangement you make with them.
Below are guidelines for laying our Corka Plank flooring. Every endeavour has been made to ensure the information given here is true and reliable. It is given only for the guidance. The company cannot accept any responsibility for loss or damage that may result from the use of this information, due to the possibility of variations of processing or working conditions and/or workmanship beyond our control. Users are advised to conduct their own tests for a particular application.
Corka Plank can be installed in all domestic areas and in most commercial areas, except in saunas, wetrooms and permanently wet areas. These floors are suitable for indoor use only. Check if the subfloor and site conditions are in accordance with the specifications described within these instructions.
Gluedown or floating?
You can install Corka Plank as either a floating or gluedown installation.
In a floating installation, the planks are simply clicked together and your floor is held in place by its own weight. Gluedown involves sticking your planks directly to the subfloor.
Floating floors are quicker and cheaper to install with no glue drying time involved – just fit and go – they are a simpler option if you want to try your hand at a DIY install and this is the option preferred by most of our customers.
Because the planks are not fixed to the subfloor, there can be a slight bounce to your floor in certain parts of the room. It is possible, for example, when you walk past a piece of furniture, you might see it move slightly due to the movement of the flooring under your weight. This is much less likely with a gluedown floor. That said, floating installation is very common and chances are, you’ll hardly notice the movement or noise….the choice is yours!
There are some circumstances in which gluing down is required:
- over underfloor heating - gluedown will provide greater stability (see underfloor heating section)
- in bathrooms and shower rooms
- in excessive heat - in rooms exposed to direct sunlight, eg through bifold doors and large windows, which could cause the surface temperature on the floor to exceed 44 ºC
- in fitness studios/gyms – due to slight movement of the machinery of static gym equipment, gluing down is advised to avoid gaps opening up between planks
- where heavy objects are to be placed on the floor – floating floors are designed to expand and contract slightly with temperature and humidity variation. If you place weighty items eg kitchen cabinets or pianos on your floor, this could prevent the normal movement and cause gaps to appear between planks
- High-traffic commercial spaces
You may also wish to consider gluing down for the following reasons:
- a very large space - where the flooring is laid in rooms larger than 325m2 (3500sq ft) or with dimensions greater than 18m (60 feet) in either direction.
- noise reduction - gluing down reduces walking noise because when the flooring is completely stuck to the subfloor there no “drum effect”
- dimensional stability – Any wooden floor, including cork, will have some movement as a result of temperature and humidity variation. This is reduced when the flooring is glued down
Corka Plank can be installed on top of most hard surfaces such as resilient floor coverings and ceramic tiles which are sufficiently fixed, completely levelled and have no loose areas. (If the surface needs to be covered, either a 4mm or 6mm plywood can be used - the thickness selected should be determined by the quality of the surface being covered.)
Soft subfloors such as carpets and similar must be removed. For Corka Plank installation no underlay is required (see details below). Old resilient floor coverings (like vinyl, linoleum, cork) must be glued so there are no loose areas. All types of subfloor must be flat, even, rigid and dry, height variations should not exceed 5mm in 2m.
It is vital that any type of concrete, screed, wooden or ceramic subfloor must be completely dry (see Moisture Protection below). While the surface of the Corka Plank flooring is water-resistant, a damp subfloor can cause dimensional instability.
Corka Plank is suitable for use with underfloor heating, following the gluedown instructions below carefully. It must not be exposed to artificial heat sources such as from heated pipes at shallow depth below screeds, or suspended pipes below floorboards. Pipes must be thoroughly insulated. In areas with excessive room temperatures or direct sunlight Corka Plank should be protected by the use of curtains and or blinds. Where exposed to temperatures of 44C or more (as can happen in areas with continual sunlight, eg conservatories and near south-facing bi-fold doors), the flooring must be glued to the subfloor. If you glue down (see instructions at the bottom of this page) you must glue the entire floor or separate the gluedown area from the floating area with transition profiles.
PREPARING THE SUBFLOOR
It is vital that any type of concrete, screed, wooden or ceramic subfloor must be completely dry. While the surface of the Corka Plank flooring is water-resistant, a damp subfloor can cause dimensional instability.
If you are laying on a concrete floor, the moisture level should not exceed 65%RH when tested with a hygrometer in compliance with BS8203-4; 2001, or 10% Wood Moisture Equivalent (WME) for wooden subfloors. Please bear in mind that new concrete can take up to six months to dry out completely, and that plaster can take 6 weeks to dry and paint 10 days. Please also note that even if a concrete slab has been down for many years, external weather conditions can introduce moisture into it via capillary action.
When installed on concrete, screed, self-levelling compound, ceramic or stone subfloors, an effective moisture barrier must always be used. For floating installations, this must be directly beneath the Corka and have a minimum SD value of 75m as described in EN16354. A polyethylene sheet with a minimum thickness of 0.2mm is recommended. On ground and basement subfloors, we recommend using two layers of 0.2mm sheeting laid crossways. Sheets must be stretched flat and free of dirt, folds and wrinkles. They should be sealed with a suitable waterproof tape.
You can use Corka Plank in bathrooms (as a gluedown installation), or areas where spillages frequently occur since it will not swell when the surface is exposed to water. However, in order to prevent moisture penetrating under the installed floor (which can create conditions for fungus or mould as well as affecting dimensional stability), a line of polyurethane sealant must be applied along the perimeter of the floor and on expansion joints.
On wooden floors/OSB
When installing on a wooden subfloor, please remove any existing floor covering first. No signs of mould and/or insect infestations should be visible. Make sure that the subfloor is mechanically fixed (screws), make sure that it is stable and shows no movement and the joints between the panels are even and firmly closed. Existing laminate flooring, wood planks or engineered wood planks must be free of tension. If there are any visible open seams and/or height differences between panels these need to be entirely removed. Seams higher than the rest of the floor must be sanded down, if they are gappy, they must be filled. Existing wood planks, engineered wood boards, OSB panels, drywall elements etc. must not be covered with a vapour barrier. Some chipboard products have a moisture resistant treatment which can seriously impair adhesion. A layer of plywood may be laid over and securely fixed to the chipboard before installation may commence.
The area below the floor should be sufficiently ventilated (back-vented skirting board) to maintain the equilibrium moisture content of the wood planks, engineered wood boards, OSB panels, drywall elements. The crawl space under the wooden subfloor must be sufficiently ventilated. Remove any obstacles from the crawl space and make sure there is sufficient ventilation (minimum 4cm² total ventilation openings per 1m² of flooring). The moisture content of the wood must not exceed 10%.
On ceramic tile floors
All loose tiles must be refixed and subfloors of this type should be levelled with floor leveller to remove any grout lines or embossing. For gluedown installation, the ceramic tiles should also be roughened and primed before installation of your Corka Plank flooring.
If you are fitting your Corka Plank flooring over underfloor heating (UFH), it should be glued down for stability. We recommend using either a water pipe UFH system set into screed or an electric system set into a reinforced smoothing compound. This needs to be thoroughly dry before your flooring is delivered or installed. There should be at least 8mm of coverage over the cables. No pipe or cable should be in direct contact with flooring or underlay and where necessary distribution board should be fitted to ensure even heat and to prevent hotspots.
The surface temperature of the subfloor must not exceed 27°C. Remember that rugs, mats and some furniture placed on top of the floor may act as heat accumulators and increase the floor surface temperature more than the recommended level. Please also note that the temperature registered by wall mounted, free-standing thermostats can be lower than the real temperature at floor level, so you need to adjust accordingly.
For detailed information on UFH installation, follow the instructions supplied by the heating system manufacturer, or contact your supplier. Any heated subfloor has certain installation requirements depending on the system and the subfloor, which need to be followed very strictly. A heated subfloor has to be dried by turning the heating on/off with a pause before any flooring can be installed, following a documented protocol. The subfloor should be in place and cured for at least 60-90 days.
The beginning of the heating phase in concrete subfloors must not begin until 21 days after complete curing of the substrate. The temperature should then be increased each day until the maximum temperature allowed according to the manufacturer's system. This maximum value should be maintained for 5-7 days without turning off. Temperature should then be decreased gradually to the off position. We recommend carrying out at least two cycles to ensure all moisture is released. Switch off for four days before taking moisture readings.
Underfloor heating should be turned off at least 48 hours before fitting your floor and alternative heat sources should be used if necessary to ensure a stable temperature between 18ºC to 22ºC during installation and for at least 48 hours afterwards, including overnight. Humidity must also remain constant in a range from 45% to 65%. This is a crucial period to ensure dimensional stability in your flooring.
When turning the UFH back on, increase the temperature by no more than 2ºC for each 24-hour period until room temperature is achieved.
You should use the same rule anytime the UFH has been turned off for a period. A similar cool-down timetable should also be used (2ºC for each 24-hour period) when turning your UFH off. Maintain a UFH frost temperature of at least 12 ºC when it is not in full use.
PRIOR TO INSTALLATION
Transport, storage and acclimatisation
Before delivery or fitting of your floor wet trades, including painting, plastering and screeds should be completed and dried, and doors and windows must be watertight.
Always transport and store the cartons horizontally. Packed tiles should be acclimatised at the job site in a dry, well-ventilated area for a minimum of 48 hours. During cold weather, acclimatisation may take longer. Store the cork in the middle of the room, away from direct sunlight (Corka Plank should be protected from heat and sunlight by the use of curtains and or blinds) as well as from walls and radiators and fully supported on wooden battens to avoid heat building up on the bottom boards. Remove tiles from packages just before starting the installation. During storage and installation, maintain temperature and relative humidity to a level consistent with the conditions which will prevail when the building is occupied. In most cases, this means maintaining a temperature range from 18ºC to 28ºC (65ºF to 82ºF) and relative humidity range from 35% to 65%. In order to achieve this, use heating or air conditioning for the appropriate time before starting the installation.
Some general tips on environmental conditions:
Low humidity will cause cork, to shrink, high humidity will cause it to expand. Low humidity is generally caused by overheating a room. High humidity by poor ventilation. Gas heaters can also cause high humidity.
Introducing plants that are watered regularly or open containers of water to a room may increase humidity, airing a room can lower it. A humidifier/dehumidifier can also be useful. It is especially important to monitor rooms that may remain unheated for long periods, where humidity may build up.
All wood, including cork, expands and contracts as a result of changes in temperature and humidity, which is why expansion gaps are needed when you are fitting it.
Prior to installation, please inspect the planks in daylight for any visible faults or damage and to ensure they are the design you were expecting as we can't take items back once they have been used or fitted. Our cork floors are natural products and each plank has its own shade and pattern. Shuffle the planks before laying to achieve an attractive blend of shades. Be sure to set aside a few flooring planks for future repairs.
Prior to installation, please also inspect the subfloor and site conditions are in accordance with the specifications described within these instructions. We cannot be held responsible for claims associated with improper subfloors, improper applications, adhesives, varnishes and the use of maintenance products not recommended, or detectable defects verifiable prior to installation.
When Corka Plank is installed as a “floating floor”, planks should not be fixed to the subfloor. The skirting boards/mouldings cannot be pressed down or restrict the movement of the floor. Provide 5mm expansion gaps to the walls and other fixed objects. Skirting boards/mouldings should cover a minimum 7mm of the floor. Transitions between two rooms and asymmetrical floor areas require extra expansion gaps in floor areas larger than 325m2 or with dimensions larger than 18m in either direction.
Underlay is not usually necessary with our Corka flooring. For additional sound insulation, we recommend Amorim 21db. Any underlay used with Corka Plank must fall into the Group 2 category, as outlined by the MMFA. Underlay should be laid at right angles to the direction of existing floorboards and should not be overlapped. Please note that underlay is not the same as a moisture barrier or a DPM which may also be required depending on your subfloor (see subfloor section). We do not recommend underlay for gluedown installations.
Padsaw or a fine-toothed handsaw, spacer blocks, pencil, set square.
Our cork floors are natural products and each plank has its own shade and pattern. Shuffle the planks before laying to achieve an attractive blend of shades.
Ideally planks should be laid following the direction of the main light source; we recommend flooring should be laid crossways to any existing floorboards.
Measure the room accurately, at a right angle to the direction of the planks. You need to ensure that the planks in the final row are at least 5 cm wide, so if necessary, the planks in the first row can be trimmed to a narrower width to ensure the final row is wide enough. If necessary, saw door frames and architraves to the required height allowing 2 mm of extra space for the planks.
FLOATING FLOOR INSTALLATION
Corka Plank is installed as a floating floor as standard. In some circumstances, as detailed above, gluedown installation is recommended instead (see gluedown installation section at the bottom of the page)
We recommend you start laying in the right-hand corner. Place the first plank against the back wall, tongue side facing the wall; using a spacer block, leave a 5mm gap between the short side of the plank and the side wall. You will adjust the gap between planks and the back wall once three rows of have been laid.
Hold the next plank at an angle against the first one, then lay it flat on the floor. Complete the first row in the same way.
Cut the final plank of the first row to the correct length, allowing for a 5mm gap between the short side and the wall, with the short side without the locking strip towards the wall. Cut boards face down when using a padsaw, or face up when using a fine-toothed handsaw.
Start the next row with the leftover piece (so long as it is at least 300 mm long). The joins between boards should not match up with those in the adjacent row, they should be staggered by at least 300mm. If the piece is too short, start with a new board and cut it in half.
Place the first plank of the new row with the tongue side at an angle against the groove side of the plank in the previous row. Press forward and lay it flat at the same time.
Place the short end of the next plank at an angle against the previous installed plank and fold down. Ensure that the board sits on the integral locking strip of the board in the previous row. Now lightly lift it up, along with the previous laid board in the same row (about 30 mm), push it against the row in front and then put it down. This movement requires some gentle adjustments to the angle as you press it into place, so that the joint becomes near-invisible.
When you have finished three rows like this, adjust the distance to the wall to 5 mm, then continue with the installation as described above until reaching the opposite wall.
If your wall is uneven, you may have to cut planks to match the wall-angle. Do not forget to allow 5 mm for the expansion gap.
Measure and cut the planks in the last row to size, allowing for a 5 mm gap to the wall. No plank should be less than 5 cm width.
If you are fitting around a heating pipe, drill the required hole in the plank, which should be 5mm wider than the pipe diameter; cut the plank at a 45º angle towards the hole. Once laid, the cut-off piece can be glued in the position again. Cover the hole with a pipe sleeve.
If you wish to remove the flooring, just lift the planks a few centimetres and tap along the joint. The released planks can then be pulled out. Never bend connected planks backwards, as this will damage them.
If you cannot angle planks to fit under a doorframe or low fitted radiator, for example, you can cut away the locking edge and glue instead using PVA glue, class D3.
To lay on stairs, planks have to cut to size and then glued down using parquet glue along with a stair-nosing of your choice.
After installation is finished, thoroughly vacuum the floor and clean it with our floor cleaner. Place felt pads under all furniture legs prior to bringing furniture into the room.
As with almost all wooden flooring, the optimum conditions for your cork planks after installation are 18ºC to 22ºC (65ºF to 72ºF) and with relative humidity in a range from 45% to 65%. If you are introducing a heating, ventilation or air-conditioning system into the room after installation, it is important to ensure no sudden changes are made to atmospheric conditions. A quick jump in temperature or drop in humidity can stress the flooring and cause dimensional instability.
For this reason any heating or air-conditioning system needs to be brought into operation slowly to allow the flooring to adapt. This requires careful measuring of the environmental conditions and an initial set of the system at the existing temperature of the room. Allow the system to run at this temperature for at least 24 hours before increasing by a maximum of 2C per 24 hour period. The humidity should be monitored during this time and maintained within the recommended limits. A certain amount of seasonal gapping is to be expected between boards and is a normal part of the performance of your cork flooring.
Please note that if your installation and building work is taking place during winter months, temporary heating should be used around the clock to maintain the optimum conditions.
Additional subfloor preparation
Subfloors for gluedown installation should be prepared as per “Subfloor preparation” section above, with the additional steps outlined in this section.
The key to success when installing Corka Plank as a gluedown is to achieve a good bond between the subfloor and Corka Plank. Proper preparation of the surface is the most important factor in achieving this bond. Whatever levelling compound is used to level, smooth or repair a subfloor surface, it will only be as strong as the surface to which it is bonded. The surface, therefore, must be sound, clean and free of oil, grease, wax, dirt, asphalt, curing compounds, latex and gypsum compounds, dust, paint, or any contaminant, which might act as a bond breaker. The methods required to properly prepare the subfloor vary with the type of subfloor, its surface and condition. Several methods of preparing a subfloor are available. Some methods are used because they are cheaper, easier or faster, depending upon the size of the job. However, taking short cuts in proper subfloor preparation can lead to installation problems and failures.
When installing over heated subfloors, be sure to use a suitable adhesive. Expansion joints in the building must not be fixed to the flooring. If it is laid and stuck across expansion joints, it may split, as it is fixed firmly in place and cannot “work” with the movement of the building.
When laying over plaster or anhydrite screeds, moisture must be <0.5%. These screeds can be applied over large surface areas without separation joints. Moisture entering and remaining in the screed after application will damage the screed. Generally speaking, these screeds must be sanded, brushed, vacuumed and treated with primers. In such cases, the reduced absorbency as a result of the primer has to be compensated by using the appropriate thickness of levelling compound (not less than 2mm) if dispersion adhesives are used.
When laying over mastic asphalt, if a dispersion adhesive is used, the asphalt must be levelled with a minimum of 2mm thickness. If contact adhesive is used, a levelling compound must also be applied, in order to avoid direct contact between the mastic asphalt and the solvents contained in the adhesive. If reaction adhesive is used, only polyurethane adhesive may be used directly on mastic asphalt.
When laying over concrete, the moisture content must fall within acceptable levels, subfloors of this type have to be roughened (e.g. by sanding, brushing with wire brushes, sandblasting), primed and levelled. To find out how much (if any) preparatory work will be necessary, it is essential to fix test strips. (Technical advice should be sought from the suppliers of levelling compounds and adhesives.)
When laying over chipboard and plywood with tongue-and-groove, fairly large surfaces can be installed without joints by gluing the tongue into the groove. Generally, only the joints between the boards are levelled or sanded. Whether or not a primer is necessary will depend on the surface quality of the boards concerned. If the joints are not glued, they will show later on the surface of the flooring.
Artificial or natural stone and ceramic tile subfloors are non-absorbent. All soiling (e.g. grease, waxes, soap, etc.) must be thoroughly removed mechanically and with detergents, especially if floors like this have already been in use for some time. Any loose tiles must be re-fixed. Subfloors of this type have to be roughened (e.g. by sanding, brushing with wire brushes, sandblasting), primed and levelled.
Wooden subfloors or particle board subfloors must be mechanically fixed, e.g. by using screws, all tongue and groove joints must be glued with a suitable adhesive and the joints firmly closed.
For gluing down Corka Plank, we recommend Bona R848T
Bona Quantum and Bona Titan can also be used
While gluing down, the Corka Plank should be cut and clicked together according to the method described in the floating installation instructions in the previous 'Laying' section above. On wooden floors, we recommend laying Corka Plank crossways to the existing floorboards.
Stir the adhesive before using. Avoid adhesive lumps. Apply the adhesive evenly on the subfloor with the recommended notched trowel. Avoid pooling of the adhesive.
Lay the floor in the adhesive, closely following the technical data sheets and recommendations of the adhesive producer. The backing of the tiles must be coated with adhesive. If in doubt, check by lifting them. When laying the tiles, use only manual pressure.
During installation, the floor must be rolled with a 50kg roller every 30 minutes, and upon completion of installation, to ensure that the tiles are firmly bedded into the adhesive.
After fitting is complete and the adhesive has dried, please follow the same After Installation recommendations as for floating installation (above).