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Flooring Site Conditions

Martin Cummins on site conditions

LAST month I talked about the fact that contract work on new building projects in particular can be very problematic because of site conditions not being right. Recent site visits have highlighted that, in my opinion the problem is growing worse.
However, the problems are not always that apparent to the main contractor. If you discuss it with them and point out the issues then their awareness is often raised significantly. This lack of awareness has resulted in many site visits which are totally worthless as the floor area is nowhere near ready for installation of flooring products and not even appropriate for moisture testing.
It seems to me that liaison between contractors (flooring and main) is more about pricing, design and schedules etc, rather than about the requirements to actually enable works to be carried out.
The following situations are the sort of thing that will be problematic to, and limiting to, flooring projects. If early stage discussions took place it may give the opportunity to carry out works when required and scheduled over the appropriate length of time.
The following is just a snippet of what still gives continual and repeated problems to programmes and suggestions as to what could be done to help both main and flooring contractors:
Power floated concrete:
The production of a hard dense concrete, typically 150mm plus is often based on the structural needs of a building. Architects can specify to very tight tolerances and, if doing it throughout an entire building, give a surface that can also itself be the finished floor.
However, the act of power floating is itself an issue. The power floating compresses the upper layers, often incorporating additives, which basically reduce the rate of moisture release so the floors will inevitably be wet. To enable further products to bond to the surface we recommend mechanical preparation such as shotblasting to remove surface hardeners used in the initial process and create a texture to adhere to.
Suggested advice to main contractors is that ‘areas of subfloors to receive resilient floorcoverings should be tamped or pan floated …not power floated’.
This can only benefit the main contractor and the flooring contractor both in cost and in time. The concrete is still likely to be wet so we will still need surface DPMs in a lot of cases so won’t be losing out on the package.
Other trades:
Most trades don’t willingly make it difficult for flooring, although sadly I have seen some cases of deliberate espionage of flooring projects (a future article perhaps). They don’t realise the impact of what their work is doing to the subsequent flooring works required.
The major problem is the introduction of moisture and contaminants particularly by plasterers, but also by painting trades. Plumbers testing the fixings can also be an issue, as they see no problem letting radiators flood the floor.
Everything falls to the ground (damn you Isaac Newton) so will always impact on our trade. Suggested advice to main contractors: ‘project drying times and therefore programme times will be extended if subfloors are not protected from moisture by other trades. Do not allow wet products to be mixed on the subfloor surface and protect the subfloor surface from plumbing water and plastering overspill by sheeting floors whilst trades are working’.
Following this advice will reduce the amount of times when you have to walk away from sites that are not ready or have to instruct delays due to further preparation being required.
l General housekeeping:
I don’t believe for one minute that this is something that is easy to do, but it is problematic when sites are allowed to be treated as walk through and storage areas. This is something that seems to happen more often these days: Materials are being stored on the screeds whilst waiting to be used.
Although this might keep the floor clean, it is preventing the drying out of the subfloors and so negates the screed manufacturer’s claims on drying times. In winter particularly it is pretty much guaranteed that trades people wandering through the site will bring in mud, and dirt which, although can be swept away later, cakes the floor and prevents drying out and also, with very absorbent screeds, adds more moisture.
Similarly joiners mess with sawdust and similar can be a big problem as it soaks up ambient moisture resulting in a wet mulch. Leaving doors and windows open during inclement weather can also be a problem for drying times.
Recommendation to the main contractors is less likely to be met with approval as it means they need to take responsibility for housekeeping, but it is worthwhile reminding them that ‘introduction of mud and sawdust will harbour moisture and delay drying’. So it is recommended that joiners sweep up immediately after work and that entrances to buildings be sheeted over or thoroughly cleaned at the end of the working day.
Storage of materials on subfloors will also greatly extend drying programmes and may result in delays to the programme.
The nett effect of the above situations will reduce the amount of non-profitable tidying up of areas before laying flooring. Preventing these issues will mean that programme time delays can be kept to a minimum.
Also, if you know that sites are not yet fully watertight I would suggest that it is not appropriate for moisture tests be carried out as they will be meaningless (the floor could get significantly more wet).
Further to all of this, it is important for the flooring contractor to appreciate the issues above. Storage of products, splashing water about, cleaning up mess and avoiding contamination (leveller onto skirtings, adhesive on fixtures, etc) have to be a priority too.
Leading by example is always the best way and will also demonstrate flooring is a professional trade, not just a general fitting service. The manufacturer will always support you in getting sites improved and enhancing our industry image.Good luck!!
Martin Cummins is UK technical support manager at Bostik. n T: 01785 272625

This article has been reproduced from the Contract Flooring Journal. You can find them at