The damp proofing costs in this article are correct as of 2019
Damp is an issue that affects many homes, and causes untold amounts of worry for homeowners, who think that solving the problem will involve complex, messy, and costly work. Thankfully, many cases of damp can be addressed with simple and inexpensive fixes - as long as your tradesperson knows what they’re looking for. If you do have to have more extensive work carried out, to address rising damp for example, then you will want to know the kinds of cost involved. Our guide will show you what you can expect to pay for a damp proofing specialist, so you can get started on your project.
There are three main kinds of damp, and each one will have different causes and different treatments - with a wide range of costs depending on the diagnoses.
Condensation is responsible for lots of cases of damp in modern homes. The result of water vapour condensing when it settles on a cold wall, floor or ceiling, the water can soak into the surface, leading to damp and mould. This moisture can be produced when cooking, showering, or drying clothes indoors, and becomes more common when temperatures drop outside. Modern homes, with good insulation and double or even triple-glazing, tend to trap moisture, meaning steps need to be taken to address the problem.
Luckily, this type of damp can typically be treated with simple lifestyle adjustments that cost very little. Opening windows where possible, making sure you are using extractor fans (and servicing or replacing them if they are not working), keeping a steady indoor temperature, or investing in a dehumidifier should be enough to tackle the issue. If damp and mould have spread, the only relevant cost for tradespeople may be redecorating work.
The second chief cause of damp is penetrating damp - where water outside of the home is coming in and causing damage. This may be due to damaged roof tiles, cracked brickwork, faulty window or door seals, or a broken gutter or pipe. If this is the case, once the problem has been identified, it should be easy to fix, with the cost ranging from £100 or so to replace a roof tile, to £500 to replace a uPVC casement window, plus any redecoration or similar that needs to be carried out.
The third cause of damp is rising damp - where moisture in the earth soaks through the foundations and walls of a house, rising up through the layers or brick and causing damage. Houses are usually built with a damp proof course (DPC), just above floor level, to prevent moisture rising up, but if this has failed, or the property did not have a DPC, then rising damp can occur. Depending on the extent of the rising damp, this can be a more costly and extensive job to repair.
As physically replacing a DPC is a difficult process that would involve a huge amount of structural work, the most common treatment for rising damp is to install a chemical DPC, removing plaster from internal walls, drilling holes into the walls and inserting a chemical which will form a barrier to more moisture coming up.
Much of the cost involved in this comes from replastering a decoration after the process is carried out. Costs vary widely between different areas and different suppliers, but a rough average is around £70 per metre of wall being treated, or around £280 per wall. Across a whole house, the costs may then rise to several thousand pounds if you need to treat every wall. It can be cheaper if you are have the plastering and decorating done separately after the treatment is carried out.
If the exterior ground level is above the level of the DPC in the wall, the DPC becomes ineffective and water can leach from the soil directly into the walls, causing damp to occur. A simple fix for this is to have the ground outside lowered by digging out the earth, and covering it over, for example with concrete slabs or gravel, to ensure the problem does not reoccur. Digging out the soil around a small house and laying gravel over the top may only cost around £400 to £500. Adding a concrete path may be as much as £2,000 for a smaller home, and twice that in a larger home.
As mentioned earlier, it is vital when dealing with damp to accurately diagnose the problem. It is always worth speaking to multiple tradespeople and getting quotes when it comes to a serious damp issue, and seeking several opinions before beginning an expensive treatment for rising damp. You can also speak to an independent surveyor to try and diagnose the issue, before taking their recommendations to tradespeople for quotes. The damp proofing industry can have a poor reputation for companies trying to sell unnecessarily invasive and expensive treatments, so make sure you’re confident that any work if really needed. Tradespeople on MyBuilder are all reviewed by previous customers to help you get a better idea of their experience and quality.