Damp Proofing FAQ

Damp Proofing

Learn what causes damp in walls and how a damp proofing process can prevent this unpleasant problem. Click on one of our damp related questions to find the answer.

Damp is a common problem, that properties across the UK will suffer from at some stage. If untreated, damp can be extremely damaging to the structure and fabric of your home.

If you are unsure what causes structural dampness, it is the presence of unwanted moisture in the structure of a building. Dampness is caused by either the result of penetration from outside or damp created within the property. There are several terms which cover damp:

  • Rising Damp
  • Penetrating Damp
  • Condensation
  • Plumbing Leaks
  • External Flooding
  • Below Ground Damp

There are several ways property damp can be caused, this includes condensation, penetration through the property from outside, and rising damp. If you are not sure whether you have damp in your home or not? Here are some symptoms that may arise:

  • Dampness and unwanted moisture, in some cases, causes the production of fungi in wood. This type of damage causes rot and mould. The worst cases of damp can lead to sick building syndrome.
  • Damp can cause plaster and paint to deteriorate. If the walls in a damp area are wallpapered, you may see the paper begin to loosen.
  • Damp can cause stains to form. These water stains come from the drying out of the fabric or staining from contaminates in the structure.

A high proportion of damp problems in buildings is caused by penetrating damp and rising damp. In most cases, dampness is caused by defects or damage to a building like defective roof coverings, render or rainwater gutters and downpipes.

Dampness can be found anywhere in a building and can affect all types of properties, old and new. It is important that when dampness is suspected you get an accurate diagnosis to determine the type of damp and the cause of the problem. Damp affects the fabric of the property and can also affect the air in the property creating high relative humidity which can lead to condensation and mould growth on surfaces.

Another sign that there is excessive dampness is that plaster, mortar and bricks may crumble in the affected area. In extreme cases, render or plaster may fall away from the affected wall.

At Richardson and Starling, we use a wide range of instruments and techniques in conjunction with our experience to investigate and identify the presence of excessive moisture in buildings. It is important that a professional surveyor assesses your property to determine what is causing the damp.

Damp can cause problems to the building and its inhabitants; therefore, this role requires competence and experience from the person undertaking the damp investigation. At Richardson and Starling our damp specialists are fully trained and use professional equipment to diagnose the type of damp.

It is important that the type of damp is correctly diagnosed as this will determine the appropriate specification to resolve the damp problem. Rising damp is often mistaken for other forms of damp, which means the wrong treatment is applied. By using one of our experienced surveyors, they will identify the damp issues and give a report and specification to deal with the problem

If you are living in Scotland, then it is vital that your property has a damp proofed structure that will protect the building from problems such as penetrating damp, rising damp and below ground damp.

A Damp Proofing system is a moisture control barrier that can be applied to walls, floors and the structure to prevent moisture from passing into the interior living spaces. Damp issues in buildings is extremely common in the UK and damp remedial treatment is one of the most common property care repairs.

Concrete and masonry walls will normally allow moisture to pass through so a horizontal and vertical damp-proof barrier is required at the appropriate position. Our Richardson and Starling teams can fit a damp proofing system that is appropriate for your property:

  • A damp-proof course (DPC) is a barrier which can be inserted through a structure above ground level to stop capillary action which is damp rising from the ground. If capillary action isn’t prevented, then there is potential for rising damp. A DPC layer is usually fitted in all masonry walls, regardless if the wall is a load-bearing wall or a partition wall to protect the wall from rising damp.
  • A damp-proof membrane (DPM) is a membrane material applied to prevent moisture transmission into the property. This is normally laid below a concrete floor.
  • Integral damp proofing in concrete involves adding water proofers to the concrete mix to make the concrete itself moisture resistant.
  • Renders and surface coating are applications of waterproof materials for resistance to non-pressurized moisture such as rain water.

There are various methods of installing a reliable, remedial damp proof course:

  • Most commonly a chemical injected DPC is inserted using a specially formulated cream or water-based product. The wall is drilled at the appropriate level by a member of our Richardson and Starling team and the chemical is inserted into the holes creating a barrier to rising damp.
  • Mortar injection DPC is used mostly in random rubble stone walls. Our technicians will drill holes in the wall and apply a specially formulated cement-based mortar.
  • Another way to apply a DPC is through an electro-osmosis system. This system uses an electric charge which is installed to the wall through wires and earthed to the ground to reverse the polarity of the capillary action and pull the damp back into the ground.

Plaster must be removed during the damp proofing process as rising damp coming from the ground not only brings moisture but also brings hygroscopic salts, nitrates, and chlorides.

Hygroscopic salts attract moisture from the atmosphere. These salts will contaminate the plaster inside the property and even after a remedial DPC has been inserted the salt contaminated plaster can still become damp. It is vital that contaminated plaster is stripped and replaced during the treatment.

Our specialists will only remove what is required and in most cases this will be one metre above the floor level. The reason why one metre is removed is because damp generally can rise to one metre above ground level however it depends on the site construction and conditions. Each case of damp is different and the repair will be determined to suit the property.

The first stage of decoration should be applied once the plaster has dried. Use water-based emulsions for the first decoration to walls as vapour will continue to dry from the wall for a period. It is not recommended that vinyl paint or wallpaper be applied as the first decoration as this could hold back the drying process and cause damage to your new decoration.

Rising damp affected walls can take up to 6 months to dry out for a 150mm thick wall and will even take longer for thicker walls. The general rule is that it will take one month for each 25mm thickness of wall to dry after the rising damp has been stopped.

The ground below your floor should have a damp-proof membrane to stop damp coming from the ground and a damp-proof membrane can be applied to the internal side of an external wall to stop damp getting to your plaster and decoration. These membranes are also used on wall areas that are below ground level that can be affected by penetrating damp from the ground.

The envelope or outside of your property should be waterproofed to stop damp penetrating your property and causing damage. it is important that the outside of the property is waterproof or water repellent which means that the masonry or render to your outside walls should prevent water penetration and should be repaired if this is not working. Special water repellents can also be used to stop rainwater penetrating the external walls if required.

Having property care completed in your home can be extremely stressful, therefore, our customers can take peace of mind that your damp proof course will be installed efficiently and correctly.

We believe that every property care specialist should give their customers long term guarantees. The length of the guarantee is detailed in our report and is automatically transferred to new owners. We are confident in the standard of our work that we are pleased to issue a guarantee you can trust.

This is a question that we are often asked by our clients. As every property and damp problem is different an accurate cost for damp proofing cannot be given until our surveyor has investigated the extent of the problem. Once our surveyor has completed your property survey we will issue a report, specification and quotation for the remedial work.

Affordable Specialist Advice & Repairs on Damp Proofing Service