Pack Away Your Broomsticks
Barry Hodges, technical manager, Mapei, says that when smoothing compounds fail it is usually down to contamination (often dust) on the subfloor:
‘YOUR levelling compound is rubbish! I put it down yesterday and it’s lifting off the floor.’ If only I had a pound for every time we’ve heard that story!
Levelling compounds are widely used within the flooring industry, to prepare all different types of subfloors, so that the chosen floorcovering can be installed. These products aren’t just designed to smooth and level the subfloor; they also provide the optimum level of absorption required for the adhesive.
Yet, we’re constantly being told that the levelling compound so carefully installed the day before – and fully in-line with the instructions on the bag – has lifted away from the subfloor.
When investigating the cause of the problem, in most cases it’s found to be contamination on the subfloor, which has prevented the levelling compound from bonding.
When installing any type of levelling compound, preparation of the underlying substrate is crucial; all contaminants or deleterious materials that could prevent the product from bonding must be removed.
It’s also important that the subfloor is thoroughly vacuumed and not swept. Sweeping causes dust to become airborne, only to settle back on the subfloor behind the guy pushing the broom!
The requirements for preparing the subfloor, prior to the application of any preparatory materials, are clearly outlined in BS 8203 Code of Practice for the installation of resilient floorcoverings. When installing any levelling compound – and always in the case of water- mixed products – a primer should be used.
This is both to aid adhesion and to prevent the formation of pinholes and blowholes, which can mirror through to the surface of any applied floorcovering.
Levelling compounds should also be installed at a minimum thickness of 3mm, to provide the required absorption for the adhesive and to ensure that the product flows and levels correctly. CFJ www.mapei.co.uk
This article has been reproduced from the Contract Flooring Journal website. You can find them at www.contractflooringjournal.co.uk.