Vinyl Flooring and Dampness

             Vinyl flooring is a broad term that includes products from manufacturers such as Karndean, Amtico, Polyflor,Altro etc etc. Karndean and Amtico only produce their flooring in a tile or plank format. However most of the other manufaturers also produce their vinyls in a 2m wide sheet.Whether it's in a tile,plank or sheet format they can all be affected by dampness, but sheet vinyl is by far the most susceptible to failure through moisture.
             Dampness does not cause any deterioration in the vinyl itself.It effects the adhesive,causing it to debond from the floor covering and thus it becomes unsightly.Lino on the other hand,which is a natural product made mainly from Linseed oil will itself, actually deteriorate and become holed. It is therefore imperative to understand where this moisture can come from and how to prevent it.
              In any new buildings a damp proof membrane will have been placed well below any flooring.However in a new concrete slab when it is first poured there is a water content in the mix.
This water cannot go downwards because of the damp proof membrane,so therefore it can only evaporate upwards.Unfortunately the moisture only evaporates very slowly at a rate of one month for every inch of the concrete floor.So if you have a normal six inch concrete slab then it's going to take 6 months for it to be free of any moisture.Add any cold weather and bad site conditions into the equation and it's easy to see that concrete although technically strong enough to work on can still be too damp to lay vinyl flooring on,especially in a sheet format.With tiles or planks and a minimal damp problem, then evaporation can occur between each tile.The sheet vinyl however just acts as another damp proof membrane and simply traps any moisture between itself and the lower damp proof membrane.Thus the moisture has no where to go and the adhesive fails.
              To test for moisture in a concrete floor a hygrometer is used.This is simply a box which is
                                               
stuck to the concrete floor with butyl tape.The moisture rising from the concrete below is trapped in the box with the air.Over a 24 hour period the hygrometer measures the moisture content of the air, the RH or relative humidity as a percentage.If the reading is 75% or less then it's perfectly ok to proceed and lay a vinyl sheet etc.If the reading is between 75 - 92% then another damp proof membrane needs to be laid.Anything over 92% and the dpm cannot even be laid and you could probably go for a swim.
                 In new buildings therefore, any dampness or moisture is usually only in the new concrete slab and it will eventually evaporate.A dpm is only required when a builder or a client can't be bothered to wait 6 months or more.In older buildings however it's quite possible they were built without any dpm at all.Rising damp might have been present indefinitely and never really have been noticed or at least caused any great problems with conventional floor coverings allowing mild moisture levels to evaporate.Vinyl sheet and even tile or plank will not normally allow this to happen.So for Karndean and Amtico which are extremely expensive and obviously for Vinyl sheet,it's quite important to test for moisture in old buildings.
                Standard acrylic adhesive is normally used with vinyls and also pressure sensitive.But both will fail with moisture.Epoxy adhesives are available which can withstand moisture attack.They're normally twice as expensive as standard adhesive and doubly difficult to use.But even with epoxy adhesives, moisture will continue to rise and it's not a cure for dampness.The only real cure is a damp proof membrane which prevents any rising dampness reaching the vinyl floor and the adhesive.

Here's a short video diary of how we lay a DPM. Just click on the link below.

                                                   http://www.youtube.com/watch?v=v7eCBNrLvjc&feature=player_embedded