Do you have ugly black patches in your rooms? There is a high chance that you have damp issues.
It’s always best to ask the help of a specialist builder who can help you plan a suitable course of action depending on the nature on the damp.
Will Sainsbury of Le Studio des Artisans suggests a few remedies below.
If you have condensation, then you probably need to look at improving ventilation. It’s always a good idea to install an extractor fan in the kitchen or bathroom as they are often humid rooms.
Check the efficiency of your heating system. You may want to consider changing old heaters or adding underfloor heating. It’s also wise to use a lower heat for long periods of time rather than short bouts of high heat.
Check out the quality of the insulation in your walls and roof. Asking your builder to inject insulation materials into your wall cavity or roof – it will be an effective as well as cost saving solution.
If you have penetrating damp you should start by checking the gutters and roof for leaks or cracks. Check the spacing of the tiles, the pointing in the stone / brick work and the flashing (waterproof membrane to protect joints and angles i.e. where a roof meets a wall) to see if there are any gaps. Also check the quality of your doors and windows to see if there are any holes that need repairing or whether the doors and windows need replacing.
Also check the nature of the render on both your outside and inside walls. If the render is non-breathable cement than this will retain water and exacerbate any damp problems. Re-rendering in a lime based render is the ideal solution.
If you choose to paint after lime rendering, then a good quality lime based paint, such as Limewash “Badigeon de chaux” from Farrow& Ball is highly recommended. Standard acrylic paints only act to serve as a membrane further trapping the humidity inside the wall.