Damp proof membrane installation

LAST UPDATED: 8th January 2023 by The Editorial Team

Two men pointing at concrete

Summary: Step by step guide and video showing how to lay and install a damp proof membrane.

Contents

How to lay and install a damp proof membrane

The penetration of water into a house and the resulting damp related problems that occur are one of the biggest causes of structural damage in properties. Dampness in brickwork and timber give life to mould and other destructive fungi. The prevention of damp is included in building regulations which set out criteria for damp avoidance.

Laying a damp proof membrane
Required layers when laying a damp-proof membrane over a concrete floor.

Laying a damp proof membrane

A damp-proof membrane is a material that can be laid underneath your flooring. It will prevent any damp rising up into the floor material. Chipboard is a particularly susceptible floor material that will suffer if damp is allowed to become a problem. The instructions here will include laying chipboard panels.

  • To lay a damp-proof membrane (DPM) you will firstly need to remove the skirting boards from around the room.
  • The floor of the room then needs to be dried out as much as possible. This can be done using dehumidifiers and heaters.
  • An insulation foam board needs to be laid directly on top of the concrete floor. This must cover the whole floor area.
  • Now you are ready to lay the damp-proof membrane. This should be laid on top of the insulation board. Any joins in the damp-proof membrane should overlap by 300mm and sealed thoroughly with a waterproof adhesive tape. The damp-proof membrane should be larger in size than just the floor space as it needs to run up the walls higher than the level of the flooring you will lay. This ensures absolute waterproof coverage.
  • Lay the chipboard panels on top of the damp-proof membrane. Chipboard does not need to be nailed or screwed into position as they are designed with a tongue and groove connection. They create a strong join when glued together.
  • Now you can finally re-fit the skirting boards. They can be re-attached into their previous position, and in doing so will cover up the DPM that extends above the flooring along the bottom of the wall.

Installing a damp proof membrane in a garage/workshop video

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The Editorial Team

The Editorial Team at lets-do-diy.com are a team of experts led by Mark Wilson. We have been creating DIY projects, articles, costs guides and product reviews since 2008. For more info see our about page.