Barriers that Keep Moisture Out
A damp-proof membrane serves to keep the walls and floors of a building dry. If the DPM is damaged or absent, the provision of special retrofit membranes can rescue the situation and protect the internal surfaces of a home from the effects of damp.
Suppose your home has damp walls, and condensation is not the cause. In that case, the prospective issue may be one of groundwater ascending from the foundation level or driving rain soaking through a wall that is vulnerable to harsh weather conditions. A retrofit damp-proof membrane offers part of a remedial package that mitigates penetrating and rising damp problems.
In the case of rising damp, water containing soluble salts rises from the ground at foundation level, drawing undesirable levels of moisture into a house. The conventional approach to counteract the wetness is to install a new chemical DPC. An essential part of damp-proofing a wall is to renew its salt contaminated plaster. New plastering should not take place within 14 days of a new DPC installation.
Even after this delay, a primary function of the replacement plaster is to block residual moisture and salts in the brickwork from migrating to new decorative surfaces. Thus the new plastering inhibits evaporation of water and prolongs the drying process.
Fortunately, fixing a retrofit damp-proof membrane to the wall overcomes these drawbacks.
‘Baseline 3 Mesh’ is a cavity-drain membrane having a shape resembling a shallow egg-tray. One side of the high-density polyethene barrier includes 3mm-high studs and the other side a polypropylene mesh-face. The mesh facilitates the direct application wall-plaster or plasterboard.
Beneficially, it is possible to attach the low-profile moisture barriers to the wall immediately after removing contaminated wall-plaster and injecting a new damp-course. Once the membrane is in place, you can instantly apply a plastering coat directly onto the mesh-face, or fix plasterboard to it. The expedited surface-finishes enables timely redecoration, whilst residual moisture can dry in the continuous air gap created by the membrane-studs.
Suppose your building has concrete floors, and you experience damp patches, wetness beneath floor coverings, or warping wooden laminates. In that case, the likelihood is that your concrete slab has a missing, torn or defective moisture barrier.
Concrete is a porous material, and unprotected floor slabs are predisposed to dampness from the ground beneath. When faced with damp in concrete floors, one possibility of rectifying the issue is to break up the floor, install a new polythene damp proof membrane and replace the concrete slab. However, less disruptive options are available at a reduced cost.
Our standard ‘Baseline 3’ is a high-density polyethene (HDPE) barrier incorporating integral 3mm stand-off studs at 20mm centres. This robust and durable membrane makes it ideal for isolating damp or contaminated floor slabs. The damp proof membrane sits on the concrete and can support a screed or insulated floating floor.
Twistfix offers two types of liquid-damp-proof membrane. The first is SBR Latex-based; it is painted on to masonry or concrete surfaces that will be subsequently protected, for example by a render-coat, flooring screed or tiles.
The paint-on DPM is robust yet highly flexible; it presents a seamless damp-proof layer.
For waterproofing directly on top of existing concrete floors, Twistfix offers a two-component water-based epoxy floor coating system, comprising a primer and a topcoat. The direct application of epoxy floor coatings on to damp floors alleviates the need to remove the existing screed, which is messy, laborious and costly. The primer soaks into the concrete, blocking its pores and improving its adhesive characteristics. The finish coat delivers a high-quality surface that is wear-resistant and crucially handles constant low levels of moisture in concrete floors.
The epoxy liquid damp-proof membrane is ideal for use in a variety of domestic, commercial and industrial environments.
For help and advice about damp proof membranes for superstructure applications, call our office and speak to one of our technical sales team. We will advise you on the correct products and methods you need to protect your home and keep it safe and dry. For advice about waterproofing membranes for sub-structure applications, please look at our Basement Waterproofing pages.