Penetrating Damp

Penetrating Damp

Although penetrating damp can look harmless, appearances can be deceptive! Penetrating damp can prove to be very damaging, even if the water does not penetrate all the way through the wall.

What is Penetrating Damp?

Penetrating damp is the process of moisture being built up horizontally through walls of the building. Often misdiagnosed as rising damp, penetrating damp can lead to further, more serious issues such as wood rot, increased heat loss, frost damage into masonry and unsightly water damage on both the outside and inside of a property.

Accredited to

Simon Lockyer

Remedial Surveyor CSRT CSSW
South West

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Worried about Damp? Call 0800 288 8660 or

What causes Penetrating Damp?

Penetrating damp is essentially water which has found its way through the fabric of a structure, usually because of an external defect. Defects come in various guises such as damaged rainwater goods (for example blocked gutters) defective pointing, porous masonry, faulty roof fabric or cracked and broken render. When it rains, rainwater usually evaporates out of the brick / stone work. However, in certain circumstances, such as periods of heavy rainfall or when the property suffers from an external defect (as mentioned above), the moisture fails to evaporate and is allowed to pass through to the inner surface.

Did You Know?

“One of the main causes of penetrating damp is the failure of a cast iron soil and rainwater pipes. This is often due to the rusting around the back of the pipe, Due to the back been inaccessible it often proves difficult to paint and maintain the pipework. This is can be a nightmare for properties as cast iron needs to be painted thoroughly to prevent rust forming. Once rust occurs, a penetrating damp problem is not far behind.”

Penetrating damp on walls

How To Identify Penetrating Damp

Fortunately, there are several indicators which make identifying penetrating damp relatively easily. In particular you should look out for:

  • A presence of a damp musty smell
  • Damage to internal walls (skirting boards) or external (roofing)
  • Patchy black mould appearing internally on walls
  • Watermarks that may appear on the masonry
  • Damaged timber as a result of the wood being saturated by damp (which could possibly have the potential of providing the ideal conditions for a wood rot fungus to germinate)

Surveyor providing a damp survey

Penetrating Damp Treatment

The most important step in treating penetrating damp is establishing and rectifying the source of moisture/ water ingress. It is more than likely that the cause of penetrating damp is down to property issues. There are on average five potential points of water ingress that can effect a property - even in new build properties.

  • Defective pointing
  • Porous brickwork
  • Cracks in render
  • Defective rainwater disposal goods

All of these areas must be kept in tip-top condition and any issues identified and problems rectified to prevent the masonry from becoming saturated.

Damp Proofing with a Karsten Tube

Identifying if Masonry is Porous

When dealing with an issue such as penetrating dampness it is best to leave it in the hands of the specialists. Firstly, your Timberwise surveyor will need to identify if your property is susceptible to dampness. Our trained surveyors can then perform a water-absorbancy test on the outside of your property. This simple test will give a clear indication of how porous the brickwork/stonework is. Our surveyors will then share their findings with you.

Weathertek Masonry Protection


Once evidence of penetrating damp has been identified, a masonry protection treatment can be applied to prevent further moisture from seeping into the property. WeatherTek is a highly advanced masonry protection treatment which penetrates deeply into the masonry before curing to form a breathable, colourless, water¬ repellent barrier. Weathertek is designed as a protective and preventative maintenance product that is designed both for homeowners and commercial property owners to protect property from penetrating damp.

WeatherTek can be applied on various building materials such as brick, stone, and concrete. Not only can WeatherTek help protect your property against penetrating damp but it also has insulating qualities improving the thermal performance of your walls by up to 29%, therefore, helping you reduce your energy bills. To find out more about WeatherTek and how it can help your home, click the button below.

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Speak to our Penetrating Damp Specialists today

It is important that penetrating damp is identified as soon as possible to ensure that the property structurally isn’t severally damaged, call our specialists today 0800 288 8660 to receive the right penetrating damp treatment or click the link below to arrange a survey online. Timberwise has over 5 decades experience in identifying and providing solutions to damp using techniques.

Request a survey

Worried about Damp? Call 0800 288 8660 or