Damp proof membranes (DPMs) are critical barriers that form an impermeable layer to block moisture migration. They protect buildings from groundwater, rising dampness, and water vapour.
DPMs come in various types, including polythene sheets, liquid-applied systems, and self-adhesive membranes. Sheet DPMs provide consistent thickness, while liquid DPMs offer seamless coverage for complex surfaces.
How Does the Thickness of a DPM Membrane Affect Its Performance?
The thickness of a DPM membrane directly influences its moisture-blocking capabilities. Thicker membranes provide superior resistance to water vapour and physical wear, making them ideal for high-stress applications.
However, thicker isn't always better. Excessive thickness can reduce flexibility and complicate installation—particularly around corners and detailing. The optimal thickness should align with site conditions and project requirements.
What Are the Pros and Cons of Using a Liquid DPM for Floors Compared to Sheet Options?
Pros of Liquid DPM
- Seamless application reduces weak spots
- Easily adapts to irregular or uneven surfaces
- Ideal for confined or hard-to-reach areas
- Faster application over large floor areas
Cons of Liquid DPM
- Requires thorough surface preparation
- Curing time may delay follow-up work
- Higher cost for small-scale applications
- Performance depends on correct application technique
Sheet DPMs provide a reliable barrier with a consistent thickness but may be harder to apply around intricate shapes. Seams can also be potential points of weakness if not sealed properly.
How Do I Integrate a DPM for Walls With the Floor DPM for Continuous Protection?
For continuous damp protection, extend the floor DPM up the wall by at least 150mm. Then, overlap it with the wall DPM by a minimum of 100mm.
Use compatible sealants or tapes to seal the joint.