Damp Proofing and Building Regulations: the Need-to Knows

It’s really important to make sure that your property is damp proof. If it goes unchecked, damp can travel through your home, causing structural damage and health problems. This is why building regulations set damp proofing standards – to avoid these risks.

Keep reading to find out everything you need to know about damp proofing and building regulations.

What are building regulations?

Building regulations are a set of rules that apply to most structures in the UK. The government writes them and local authorities enforce them. They’re in place to ensure that all buildings are safe, relatively energy-efficient and accessible.

When you do any work on your home, you need to make sure that you follow any relevant building regulations. In some cases, you may need to get building regulations approval. This involves telling your local authority about the work you’re doing in advance as well as following regulations.

What do building regulations say about damp proofing?

There are slightly different building regulations about damp proofing for different parts of a building.


Building regulations say that all new buildings should have damp proof courses to prevent rising damp and in some cases courses to prevent penetrating damp. Damp proof courses in walls should:

  • Be at least 1.5cm above ground level if the wall is external
  • Join up with any damp proof course or membrane in the floor
  • Be at least 2.25cm above the bottom of a cavity wall cavity unless a cavity tray is installed

If you’re fitting a new ground floor, building regulations say that it needs to have sufficient structural support and resistance to ground moisture and heat loss. To meet these damp proofing requirements, you should install a damp proof course or membrane under your floor. This should join up with the damp protection in your external walls to be most effective.

You can find more details about damp proofing building regulations by reading building regulations Approved Document C.