Installing A DPM Is A Fail-Safe Approach
Mark Leigh on dpm technology and current trends
THE additional cost of dealing with the failure of floorcoverings is estimated to be four to six times higher than the predicted price of applying a high performance damp proof membrane at the time of initial installation. This shocking figure is a concern for specifiers and developers dealing with residual moisture in new
In-situ concrete floor construction and the use of sand/cement screeds still predominates. And the water required in the mix design to hydrate the cement, as well as to make batches workable, still takes up to a year to dry out.
Problems normally arise when project teams are obliged to push on with the fit out of buildings before the moisture incorporated into the floor construction has had any realistic chance to escape. For those who have not seen the results of laying largely impervious sheet materials on sweating substrates, the outcome earns the nickname ‘measles’.
The moisture molecules migrating to the surface of the subfloor cause the adhesive to re-emulsify and return to a liquid state, creating small but noticeable lumps. Taking up the sheet vinyl or other material is the only practical means of resolving this unsightly mode or failure.
Damp proof membranes are a critical part of flooring systems, often forming part of the barrier between the inside and outside of a structure, though we would always expect the main contractor to lay polythene or some similar membrane beneath a new ground bearing concrete slab.
Despite the widely acknowledged value of fluid applied DPMs and the fact that demanding programme timetables are the norm these days, many clients still try to avoid the perceived extra expense of using a system such as ours. It is all about the cost time equation and getting the building ready for occupation as soon as possible, but not specifying a high performance DPM is almost always a false economy.
In fact the time required to install and cure a damp proof membrane such as Tremco ES100 One Coat DPM need not be more than a day or two, with the flooring sub-contractor often being willing to work outside of normal hours to minimise disruption. The operational parameters of modern membrane systems are impressive, being suitable for use where hygrometer readings can rise as high as 97%. Various application procedures are detailed in the technical literature, dependent on the actual reading, but the basic technique of using a notched trowel and roller ensures the correct coverage is achieved.
Do look at any materials employed as part of flooring installation, not simply in isolation, but as elements to an integrated system solution. This is why product compatibility is paramount and clients must ensure that any underlayments, adhesives or other applied materials will not present problems of their own.
In an effort to explain both the problem of residual dampness, and the performance benefits of contemporar y damp proof membranes to specifiers, we have developed an independently cer tified CPD seminar which explores the failure modes, together with the associated cost implications of not addressing damp in the floor substrate; then goes on to outline potential remedies.
Entitled Surface membranes and their application, the seminar has been developed in consultation with the Royal Institute of British Architects (RIBA), and offers consultants or contractors one hour’s CPD time.
So the message is getting out there, but we would still like to see developers including a high performance damp proof membrane as an automatic element to their floor system whenever the relative humidity readings indicate a potential problem. It is far better to take the preventative, fail safe approach than to be taught a ver y expensive lesson.
Mark Leigh is national sales manager for Tremco illbruck
This article has been reproduced from the Contract Flooring Journal website. You can find them at www.contractflooringjournal.co.uk.