Damp-proofing walls

Damp-proofing will protect your home and will save you money in the long term by preventing more serious damage, like dry rot.

Level of difficulty

Level 3: Advanced

Things you’ll need

DIY chemical DPC injection kit
DIY damp-proofing cream
Electro Osmosis damp-proofing kit
Club hammer
Power drill

The steps to follow

Check the following to see what’s causing rising damp

  1. Check that the wall’s airbricks are free of debris
  2. Check whether a step, path or other concrete slab has been built next to the wall, to a level higher than the damp-proof course (DPC) strip. If this is the case, the concrete may be passing moisture or damp through the wall. You can solve this problem by inserting a layer of DPC strip between the wall and the concrete
  3. If you have a garden wall, check that it has a horizontal and vertical DPC strip. If not, insert a vertical DPC between the garden wall and your wall
  4. If you still can’t find a solution to your problem, you’ll need to damp-proof your wall. Chemical DPC and Electro Osmosis Damp Proofing are the best methods to damp-proof your walls

Injecting chemical DPC

  1. Remove the skirting board and hack off the plaster with a club hammer
  2. Drill some holes downwards at 150 mm (6 in) above floor level and 75 mm (3 in) deep or 90% of the wall thickness. The holes should be evenly spaced at 112 mm (4.5 in) along your wall
  3. Prepare the injection pump; insert the pick-up hose into a drum of DPC fluid
  4. Insert the injection pump’s nozzles into the holes and inject the DPC fluid. This fluid will disperse into the mortar and act as a water repellent layer
  5. You can stop the injection when the surface darkens and becomes wet
  6. Leave it to dry for about a month before filling it with waterproofing agent
  7. Reinstall the skirting board

Osmotic Electrical System

  1. Install an electric charge system DPC course, aka: Osmotic Electrical System. This is recommended on thick walls and is easy to install. You can also hide it behind skirting boards
  2. Remove the skirting board
  3. Drill enough holes to accommodate the number of titanium wires (anodes) included in the kit. Drill downwards at 150 mm (6 in) above floor level and 75 mm (3 in) deep, at one metre space intervals
  4. Insert the anodes, included in your Electro Osmosis Damp Proofing kit, into these holes. Avoid inserting these wires near water or central heating pipes. If you plan on doing so, you should insulate these pipes
  5. When finished, fill the hole with mortar and water-repellent agent
  6. Install the earth rods in the ground
  7. Plug the power plug into the main power supply
  8. Reinstall the skirting board

Please note that all our DIY guides and ‘Expert answers’ advice have been written strictly for reference only. Rated People do not accept any liability for any damage caused to an individual, property or anything else as a result of following our DIY guides and using our ‘Expert answers’ advice.

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