What is penetrating dampness?

Penetrating dampness is defined as the entry of water into a property. This includes leaking roofs, defective guttering, entry of water through defective windows, poor pointing, spalled brickwork and down chimneys. It can include leaks from plumbing or drainage systems, either inside or outside a building, entry of water through earth retaining walls or into cellars below ground level.

In all cases the solution to penetrating dampness is to eliminate the moisture at the source and allow the area to dry out – easily done in some cases, but impossible in others without going to extremes of cost. For example, a leaking gutter can be easily repaired, but the penetration of water from a high external ground level into a cellar is more difficult to deal with.

Penetrating dampness causes several main problems :-

  • Damage to masonry, plaster, paint work; mostly by staining, which sometimes requires replastering.

  • Moisture in timbers; which can lead to decay by wood rot or insect attack.

  • Cold, wet internal surfaces on which condensation can occur.

How to fix it?

The first thing you will need to do is look at the area and think if there is anything obvious in the locality that could explain the problem.

As a guide the following specialists will normally provide assistance in findings the problem and undertaking any repairs/remedial works needed to eliminate penetrating dampness:-

Problem Area


Roof, guttering, roof gullies, down-piping, chimneys Roofer
Pipes and internal drainage Plumber
Brickwork, pointing, external drainage, windows, path and ground level reduction Builder
Plaster, other wall linings Plasterer / Damp-proofer
Basement/cellar water-proofing Damp-proofer

Having eliminated penetrating dampness and allowed a period of drying out, repairs to timbers and plaster should be undertaken. This may include timber replacement or in-situ timber treatments. Only suitable renovating plaster should be used for replastering as conventional plasters are not formulated to deal with residual moisture or salt contamination (for example dark staining salts in chimney breasts). Areas that have become very damp and those subject to heavy salt contamination (chimney breasts) may require dry-lining (application of plasterboard over a damp-proof membrane) or tanking / structural waterproofing.

Left in this condition for long enough, this leaking soil pipe will not only cause a hygiene problem, but also lead to internal penetrating damp. Problems like this should be sorted out as soon as they are noticed.

To notice them, you have to wander around your house and LOOK. Sounds obvious; but inspect everything – up, down, left, right and centre. The best time to do this is just after rain, and for guttering problems during rain.

Getting the things outside the house right, and this includes the roof covering, will ensure the house stays weatherproof.

It’s rare to find all three types of damp located in one area – but this is probably it.

The overhead guttering outside was leaking badly. The 9 inch solid wall was so poorly pointed water could easily get through the wall.

The wall had no damp proof course and external ground levels were too high.

Internal growth of black spot mould is an indication of the occurrence of condensation.

The trouble is you need to eliminate all of them – one by one to solve the damp problem inside.

The significance of long periods of rain and its effects on properties is seen in the photo.

The “shadow” of the wet bricks below the over-hanging roof in this photo can be seen clearly, with all the brickwork in the dark areas being saturated with water.

The wall will be drying out – losing water by evaporation – and this is an energy consuming process, the energy for which comes from the wall. The result is that the wall temperature falls significantly and will, therefore, form a heat sink for the heat inside the house. This makes cavity wall insulation very important on this wall, but there can only be about 50 mm of it in the cavity so that the insulation value is small.

It would have been better for the wall to never get wet in the first place, and this can be achieved by breathable silicone or acrylic masonry water repellents applied directly to the brick surface.

Customer Feedback

Damp Control – Middlestown, Wakefield, WF4

February 2019
Very happy with the work undertaken. Paul is a credit to your firm. Very polite and happy to explain everything in detail. It's easy to see he is happy in his work and has a desire to achieve a quality job.

Penetrating Damp, Rising Damp & Wet Rot Repair – Roundhay Ave, LS8

December 2017
I just wanted to let you all know what a great job I feel you have done. Each time I called, Gemma was really lovely, helpful and polite. Matthew who came to do my survey was really helpful, answering all my questions at the time and after. The gentleman that came to do the work was really nice, again really helpful, hardworking and did the job as tidily as he could. I was also very pleasantly surprised that my final bill was not more than the estimate I had been given, as I understood when it came to doing the work, more was needed than initially expected. A fantastic experience and I would definitely recommend you. Thank you very much.  

Preserving World Heritage Site – Caroline St, Saltaire, BD18

May 2017
Following a recent survey, your company carried out damp treatment works and provided guarantees. All stages of my experience of Yorkshire Dampcourse company were good -from my initial phone call, survey & report and then completion of the treatment work. The service you provided was prompt and efficient throughout. I was delighted with how the treatment work & plastering was completed so quickly to a high standard. He protected the rest of the house from dust as possible and promptly cleared away at the end.  Thank you

Another happy Guiseley customer (Tennyson Street)

<em>"All the work I was expecting has been completed and to a standard I am happy with. All the waste was removed and I was happy with the way you left the property.</em> <em>The technician was very nice all day and very helpful."</em>