How and where to use Liquid DPM
Hi, my name is Andy Parkin. I am the Managing Director of the Multi-Award Winning Speed Screed. In this article, I am going to give you the low-down on liquid DPM, where and how it is used and some of the things you need to consider.
What is liquid DPM?
Liquid DPM is a system that is used over a base floor. The liquid membrane forms a strong seal and makes a permeable layer to enable moisture to evaporate off. Once set, you can then apply your screed flooring to the DPM base.
Types of Liquid DPM
Mastic Asphalt – this is the earliest form of liquid DPM and is usually laid on the top of another membrane or a fibreglass surface. The main drawback of mastic asphalt is that it may become brittle over time and cracks can then form. In heavy traffic areas, there can be damage to the membrane and there are a number of health and safety concerns that need to be addressed when laying this membrane.
Epoxy Resin – this is the newest type of liquid DMP. As a result of new technological advances, this type of membrane adheres well to the base surface and also allows for moisture evaporation without potential damage to surface flooring layers.
Applying a Liquid DPM
Liquid DPM can be applied to the base layer using trowels, rollers, squeegees or brushes. More than two applications are needed for the best results. In order to make sure the base is completely covered the second coat should be laid at right angles to the first.
How do Liquid DPMs work?
The DPM dries to form a permeable membrane that allows moisture to evaporate off in a controlled way.
Performance can be significantly affected if the liquid DPM does not adhere to the base layer properly, therefore careful preparation must be done to make sure that the receiving surface is level and free from debris. Additionally, once the base is prepared the liquid DPM should be applied evenly, giving a uniform coverage, free from holes and finished to the correct thickness. If these basic steps are not taken the floor could fail due to increased rates of moisture passing through the layer.
Why use DPMs?
Most pre-1970s constructions often have poor DPM because the inclusion of membranes in construction was not routine. Since then homes have been built using sheet membranes but these were often incorrectly installed or damaged. Over the years the demand for better damp proofing has increased leading to the development of more advanced solutions like liquid DPM.
To conclude, liquid DPM is a great addition to current damp proofing solutions. The decision to use it should be made by looking at the individual project, the type of location and the demands placed on the flooring surface. Additionally, not all final floor finishes can be used with liquid DPM so check with the manufacturer first. Please contact us for more help.