Damp Proofing

Our damp proofing guide has been designed to help you identify and repair damp issues before they turn into major problems that require expensive treatment to rectify.

If you feel that you would benefit from professional damp proofing advice to diagnose the issue and create a custom treatment plan to leave your home fresh, safe, and dry, then you can talk to our fully trained and qualified specialists by clicking the button below.

Damp proofing is a general term that covers methods and treatments used to prevent damp from being absorbed through walls or floors into the interior of a property.

The actual method of damp treatment you require varies depending on the actual cause of your issues. Our guide will now go on to look at the various types of damp to help you identify which is present in your home and what form of damp treatment you need to solve it.

If you require damp proofing services, then usually it is because you are seeing damp walls caused by either rising damp,  penetrating damp, or condensation.

These damp problems result from water ingress from an external source, groundwater rising into the wall through capillary action, or inadequate ventilation.

Rising damp will only occur when an existing damp proof course (DPC) has been bridged or damaged in some way. This allows rainwater in the ground to seep into the building through bricks and mortar by a process called capillary action.

It is important to note that it will only ever affects the ground floor, and symptoms on internal walls include:

• Damp walls and a ‘tide stain’ above the skirting board
• Evidence of salt deposits left on the wall
• Damaged or rotting skirting boards, plaster and wallpaper

Water leaking in from outside the property is the main cause of penetrating damp. This will usually manifest as localised damp patches on a wall or ceiling.

Broken downpipes and gutters, cracks, faulty joints and corroded seals are all contributing factors. Leaks from inside can cause problems too, and wet rot can often accompany damp from faulty plumbing or leaking washing machines and showers.

The signs of penetrating damp are:

• Visible damp or even moss growth on external walls
• Walls and ceilings with damp above the first floor
• Wet plaster (if over 1m high)

Condensation is caused by excess humidity and poor ventilation. It also creates ideal conditions for black mould to grow.

Look out for excessive moisture or water droplets and black spot mould around:

• Walls, ceilings and attics
• On furniture, curtains and other soft furnishings
• ‘Hotpoints’ like bathrooms and on or around windows

Now that our guide has helped you to spot the signs of damp and identify which is present in your home, we will now look at the various forms of damp treatment and which one is right for you.

Most properties should have evidence of a Damp Proof Course about 150mm (6inch) above ground level. This may be seen as a slightly thicker mortar course with evidence of a slate or bitumen sheet. These materials are fairly resilient, however, they can degrade, become damaged or bridged by modifications, leaving your home vulnerable to rising damp.

To damp proof properties affected by this, the most common solution is to inject a silicon remedial damp proof course which creates a waterproof barrier, effectively preventing moisture from seeping into, and damaging, affected walls. DPC injection is a fast-acting and permanent method of damp proofing and allows affected walls to be redecorated shortly after installation.

Naturally, the first step is to solve the issue that is allowing the water ingress in the first place. In some cases, this just requires a simple DIY solution to solve faults such as a damaged roof tile or crack in the external wall, although it may be the case that a professional restoration service is required.

Frequently the homeowner will be required to strip the affected area of the plaster and to install a layer of damp proofing membrane in the wall before replastering.

Unfortunately, this type of damp has the potential to create more serious issues like wet or dry rot, so we would suggest that you should thoroughly investigate the property for signs of rot or associated damage before attempting to replaster the wall. Otherwise, you may install damp proofing measures required to fix the initial cause, while much worse issues continue to fester inside the property.

The key to damp proofing properties affected by condensation is achieving consistent relative humidity. This can often be remedied with DIY or lifestyle changes, but in serious cases treatment will require a coating with anti-condensation paint or the installation of mechanical ventilation units.