Average damp proofing costs

Summary: How much does damp proofing cost, average damp proof installation costs and average cost of materials.

Rising damp in the home can cause damage to the property if left untreated, so it’s vital to identify and treat the problem. Tell tale signs that you having rising damp in your home include decayed skirting boards, peeling paint and wallpaper and crumbling or salt marked plaster.

Rising damp occurs when ground water rises up through walls by capillary action. The dampness is rising through the mortar beds of the bricks, rather than through the brickwork itself. If left untreated it could rot floor joists and other timbers, even leading to the development of wet or dry rot.

Average Cost

Factors to consider

Rising damp is often misdiagnosed so before you begin any work it’s vital that the damp is investigated thoroughly by a trained surveyor, preferably one who is CSRT (Certificated Surveyor in Remedial Treatment) recognised and the problem correctly identified. This could cost around £250 but ensures you know the exact nature of the problem and can apply the appropriate remedy.

If you do have rising damp, then you need to install a damp-proof course (DPC) to protect the property. Damp proofingwas uncommon until the 1950s so many older properties may never have been treated while in others the DPC may have deteriorated or the work not carried out properly in the first place. Sometimes a DPC has been ‘bridged’ by earth from the garden or raised pathway and this can be sorted without the need for any expensive work, simply dig away the soil to allow the DPC to do its job effectively.

Damp proofing is basically the provision of a barrier across a wall to stop moisture naturally rising from the ground. Thanks to the development of new DPC creams it’s now possible to carry out damp-proofing yourself as a relatively simply DIY job. The previous system required a high-pressure injection of liquid which was considered tricky, even by professionals. The new creams however are easy and reliable to use and allow DIY’ers to carry out their own chemical DPC.

The cream comes in sealed plastic, disposable cartridges, ready to fit into a standard skeleton gun. You need to use a drill to create 1.2cm diameter holes 12cm apart in the brick mortar course. Alternatively you can go through the brickwork at an angle to reach the mortar course. These holes should be a minimum distance of 15cm above ground level. Blow or vacuum holes to disperse the dust. Next, attach the cartridge tube to the extension nozzle and put it into the skeleton gun, then insert the cream from the base of the hole towards the outside until you fill the hole. After you have carried out the damp-proofing work you need to wait for the wall to dry out before re-plastering and re-decorating.

If you feel damp-proofing is too big a job to undertake yourself then get the work done professionally and use a reputable firm. Asking friends or neighbours for a recommendation is a good way to find someone to carry out the work and make sure any company you take on is a member of the Property Care Association. The PCA is the main trade body for industries covering, amongst other things, damp-proofing. The firm you employ should provide you with a full report of the problem, recommended treatment and a damp-proofing guarantee which could be useful to have if ever sell your house.

Costs to consider

The cost of getting a professional company in will vary depending on where you live and the extent of the problem but is likely to start at around several hundred pounds. If you are doing the job yourself then you can buy DIY damp-proof cream kits online or from DIY stores. The cost will depend on the size of the area you need to cover and any extra bits of equipment you may need.

However you get the damp-proofing work done, you will need to factor in the costs of re-plastering and re-decorating, especially if you hire a painter and decorator to do the job. Even if you do it yourself you will still need to buy the materials and paint.

Following a DPC re-plastering will be essential and in some cases you may be better off using an Air Gap Membrane instead of sand and cement. Whichever method you choose, plastering walls which have been treated for damp is different to normal plastering jobs. Once the plastering has been done, do not carry out any decoration for at least one month and then only apply a thin coat of breathable emulsion paint. Do not repaint for at least three months and avoid wallpapering if possible.