Call usSub-floor preparation for design flooring
Design flooring such as Amtico, Karndean and Marmoleum is specialist flooring that remains beautiful for 20 years or more. To ensure it stays at its very best, manufacturers have exacting standards for the preparation of your sub-floor before your flooring is installed.
Wooden sub-floors
Before Amtico, Karndean or Marmoleum flooring is fitted over any type of floorboard, chipboard or plyboard, etc., it is essential to make sure that the top layer is as smooth, sound and clean as possible. This is most effectively achieved by installing a plywood overlay. We recommend a minimum 6mm exterior grade to WBP (weather and boil proof) plywood. A thicker grade of plywood may be required for particularly heavily trafficked commercial areas.
The plyboard should be laid with staggering joints and secured with countersunk screws every 6” or divergent staples every 4”. The joints are then filled with a micro coat filler which is left to dry before being sanded until smooth. The sub-floor should be swept thoroughly and kept dry until the new floor is installed.
If the old floorboards are cupping or uneven, they should be replaced or repaired and sanded until level and sound.
To guarantee a seamless floor that ensures the joints of the plywood are not visible once the installation is complete, we recommend a smoothing screed such as Stop Gap 700. This has small fibres mixed within it so that it becomes flexible and can move with the floor. Stop Gap 700 is available at an additional charge of £15 per square metre.
Alternatively, we can use Versalay or Jumpax – a floating system of DPM (damp-proof membrane), a thin underlay and two sheets of MDF, stuck together. Available for £35 per square metre, this is ideal if your sub-floor has damp areas or is a mixture of different flooring types.
Note: Even if all the above recommendations have been correctly followed, shadowing of the joints through the tiles can occur. This is not a manufacturer’s fault but something that can happen when certain colour of tiles and lights reflecting off the floor highlight joints on the sub-floor. This will not cause premature wear to your design flooring or affect your guarantee but do ask us if you have any concerns.
Concrete sub-floors
When Amtico, Karndean or Marmoluem flooring is to be laid on new or old concrete sub-floors, certain procedures must be followed to prevent the floor from falling. Initially, it is essential to conduct a moisture test to ensure the moisture content is not aboves not above 75% relative humidity. Once your order is placed, this is carried out free of charge.
If the floor is found to be above this figure, we can either let it dry naturally, which takes approximately one day per one millimetre. Alternatively, we can install a surface damp-proof membrane (DPM) for around £300 per 15 square metres.
If humidity readings are correct a suitable leveling compound should be applied at a minimum depth of 3mm, This smoothing compound should be water-based, rather than latex. The compound takes about a day to dry, following which any indentations can be filled with a micro coat filler. The floor will then be sanded and made as smooth as possible.
Where sub-floors are half wood and half solid floor, there will always be a weak point where the two materials join. To create a seamless sub-floor, we recommend using a flax smoothing screed such as Stop Gap 700, which is available for £15 per square metre. Alternatively, we can use Versalay or Jumpax – a floating system of DPM (damp-proof membrane), a thin underlay and two sheets of MDF, stuck together. Available for £35 per square metre, this is ideal if your sub-floor has damp areas or is a mixture of different flooring types.
Note: Although we work hard to make the join as good as possible, wood floors are always subject to some movement which may shadow through when certain light reflects on this area. This will not cause premature wear or affect the guarantee of your design flooring.
For more information on creating the perfect sub-floor, call or visit us in our North London showroom.
