Be cautious when dealing with damp specialists and look into the products they are trying to sell you. It might be possible to cover a problem up, but there is no guarantee that it won't return, and it could magnify the costs involved with putting it right later down the line.
Avoid
- Cement / gypsum products
- Plastic / resin products
- Tanking
- Sealants
- Injection DPC
- Damp-proof paints
The science
Breathability is a blanket term for permeability, capillarity and hygroscopicity. Modern damp-proofing methods will often harm the fabric of the building and at best cover up the damp issue. Sealing or tanking your walls won't solve the issue, as the slightest crack will draw in moisture. Moisture will always be present within a solid wall; it should be allowed to evaporate naturally. Any plastering, rendering or pointing performed on a solid wall should be done with a breathable lime-based material.
Porous materials
Soft building materials like old bricks, lime mortar and stone are very porous: they are like sponges and absorb water. If sealed, they can no longer release the moisture properly.
Capillary action
Liquid water being able to move through the wall. Often misdiagnosed as "rising damp" — watch out for injection DPC that will often be sold to you as the cure for this. The main cause is the use of impervious materials and wrong ground levels.
Permeability
Water vapour's ability to move through the wall naturally. Your internal walls should absorb excess water vapour from breathing, cooking and showering; the external face of the wall can then evaporate the excess moisture.
Damp survey
When you get in touch about your damp problems, we now offer a written survey in which you receive a detailed report highlighting the issues, suggesting remedies, and giving a price to solve the issues found. We will recommend the best course of action. Please note that we are not RICS accredited. Due to high demand, we are no longer able to come out and give free advice. Our detailed report will include an estimate to fix each issue and will include advice as to what you can do to help remedy the problem. Get in touch to arrange a survey from £95.
Key points
- Solid walls must be allowed to evaporate moisture naturally
- Any plastering, rendering or pointing on a solid wall should use a breathable lime-based material
- "Rising damp" is often misdiagnosed; injection DPC is not the cure
- Written damp survey available from £95 (we are not RICS accredited)