Damp patches on walls – stains that may be brownish to light yellowish in colour. – Determine that the brickwork/masonry is actually wet and not just the plaster or wallpaper.
Black mould on walls
Damp can cause spores of black mould to form on walls, ceilings and around window frames and doors. Mould is one of the most visible signs of damp in the home and can be harmful if left untreated, particularly for those with respiratory problems like asthma.
most likely, the walls are wicking water up from the ground. Check your downspouts to make sure all water is being pushed far away from the house. Is the ground properly sloping away from the house? Is the back ``garden''/patio sloping away from the house?
The most common cause of both rising and penetrating damp is inadequate ground and surface drainage. Excess water from downspouts, runoff or saturated ground can easily penetrate even the tiniest cracks in your foundation, or wick through porous walls. This moisture can make your walls feel wet.
To resolve rising damp, either a chemical or osmotic damp proofing course (DPC), or a new damp membrane must be installed. A DPC is often used and is injected via holes in the masonry, the DPC repels water whilst a damp membrane acts as a physical barrier to stop damp.
Unfortunately, you can't just paint over damp or mould in the hope it will disappear. Even if you use waterproof paint, it can still seep through over time. Depending on how bad the problem is, you may be able to remove the mould by cleaning the area without repainting.
There is no clearer sign of damp than actual discolouration of your walls, ceilings or floors. Whether it's the mark of the damp itself or yellow or brown discolouration, you're bound to spot this sign of damp in your property as it can ruin the look of any property.
Dehumidifiers can indeed aid in drying wet walls. After a flood, leak, or a spell of extreme humidity, damp walls can develop. A dehumidifier removes extra moisture from the air, lowers the humidity, and stimulates evaporation.
Water damaged drywall often shows discoloration and water stains. Mold frequently appears in areas prone to moisture such as bathrooms and basements. Identifying water damage early can prevent further structural compromises. Sheetrock, similar to drywall, swells from water exposure and loses its strength.
You can generally identify rising damp by the damage it causes to the internal walls. Rising Damp creates noticeable tide marks that usually appear around halfway up the wall. In addition, as the moisture absorbed from the internal brickwork travels up it can cause wallpaper and plaster to start cracking or peeling.
Condensation
This may appear to be rising damp and can easily be confused. Condensation problems within a building are usually indicative of humidity and ventilation problems within a property. It is often believed to be caused by building defect, but that is usually not the case.
The misdiagnosis of rising damp
Rising damp is a complex hazard to identify and is often confused with other forms of damp, particularly condensation.
Rising dampness is the priciest issue to fix, and it occurs when dampness rises up your walls through capillary action, often causing extensive damage to paint and plaster. It can also cause structural issues and weaken your walls, which is why it costs more than the other two types to fix.
Common signs of penetrating damp include things such as:
Damp patches (often looks like a brown stain) suddenly appearing on an interior wall, ceiling or near a chimney breast. Wet and crumbling plaster. Large bubbles appearing under plaster (can often lead to holes in the ceiling if left untreated).
The worse a damp situation gets, the more it's likely to cost to repair any damage. Most standard buildings and contents home insurance policies do not cover damage caused by damp and condensation.
Tape a square of aluminium foil to the wall and leave it there for a day. On inspection, if the side facing away from the wall is wet, you have an issue with condensation. If the inside of the foil is wet, you have penetrating or rising damp.
If you find you are noticing wet walls on a regular basis, you may need tanking of the walls to prevent this problem and to stop related damp issues. If the walls are particularly wet, it could take weeks or even months for them to be completely dry.
Once the surface is free of mould and dry, it can be painted with a damp seal or stain blocker paint which will ensure that the staining does not bleed through the emulsion once completed. Once dry, touch up with the same paint used elsewhere on the wall or ceiling.
Use fans to move air around the damp walls. Also use dehumidifiers, which can help remove moisture from the air and walls. Professionals use tools like moisture meters, infrared imaging devices, dehumidifiers and heavy-duty fans. That ensures the walls are truly dry before further repair, painting or refinishing.
Breathable Paints
This type of paint is ideal for places with condensation problems, as it allows the wall to “breathe”. This means that it allows water vapour to pass through, preventing it from accumulating and turning into droplets that wet the surface.