Ways to control Internal and external damp

Damp can come from many sources, some of which are more obvious than others. Damp may also not be the direct result of water penetration but is caused by condensation or thermal bridges. The first step to making your home damp-proof is understanding the types of dampness problems that are related to your exterior house wall.

Internal dampness is controlled with a specialist called a plasterer who uses breathable lime plasters mixed with sand and water. This treatment will dry out any moisture that is on the inside of the brick or plaster where it cannot evaporate into the atmosphere.

Exteriors are treated differently depending on whether they have been sealed or painted previously, as these affect how well they breathe and absorb water vapour. If the exterior has been sealed previously it is important to identify what type of sealant was used, as this will affect which method of damp control that you should use in the future.

If there are no signs of water penetration or staining then no action is needed on an external wall that uses lime render over brickwork with a breathable paint. Lime renders accept and break down the salt in damp, but if your render has been painted previously it is important to ensure that this paint has not become a barrier or waterproofing layer which could lead to future moisture problems.

1. Identify the type of dampness problem

In order to find out the type of dampness problem you will need to conduct a careful inspection. To paraphrase “A  stitch in time saves nine” meaning that if you are proactive about your dampness control it will save much more work, hassle and money in the future.

2. Determine if it is internal or external

The first step to identifying the type of dampness problem that you have in your home is to conduct a careful inspection. You will need to identify any signs of water penetration, moisture on the inside brick wall or stains from moisture on an exterior wall.

If there are no signs of water penetration or staining then no action is needed on an external wall that uses lime render over brickwork with a breathable paint. Lime renders accept and break down the salt in damp, but if your render has been painted previously it is important to ensure that this paint has not become a barrier or waterproofing layer which could lead to future moisture problems.

3. Use lime plaster to dry out moisture on the inside of your home’s exterior wall (internal)

Lime plaster is the most commonly used damp control product of choice by plasterers. The plaster is breathable and will dry out any moisture on the inside of the brick or plaster where it cannot evaporate into the atmosphere.

Lime renders accept and break down the salt in damp, but if your render has been painted previously it is important to ensure that this paint has not become a barrier or waterproofing layer which could lead to future moisture problems.

4. Find a plasterer and use breathable paint for the outside of your home’s exterior wall (external)

In some cases, a more extensive treatment is required for both internal and external dampness. This will mean hiring an experienced specialist called a plasterer who will use breathable lime-based mixes that dry out any moisture on the brick or plasterwork.

External dampness is controlled with a specialist called a plasterer who uses breathable lime plasters mixed with sand and water. This treatment will dry out any moisture that is on the outside of the brick or plaster where it cannot evaporate into the atmosphere.

5. Seal any cracks in these walls that may be causing water penetration

Seal any cracks in these walls that may be causing water penetration. You can cover the cracks with waterproof sealant, either applied directly to the crack or through holes drilled into the wall. Check for gaps around the base of the wall and replace any old mortar.

Clean rain from all paths, roofs and gutters regularly to avoid water penetration. You should also ensure that gutters are kept clear otherwise they may overflow onto the walls causing dampness. In addition, clean down spouts regularly as they can cause rusty streaks to appear on the brick.

Conclusion

Damp can come from many sources, some of which are more obvious than others. Damp may also not be the direct result of water penetration but is caused by condensation or thermal bridges. The first step to making your home damp-proof is understanding the types of dampness problems that are related to your exterior house wall. Internal dampness is controlled with a specialist called a plasterer who uses breathable lime plasters mixed with sand and water. This treatment will dry out any moisture that is on the inside of the brick or plaster where it cannot evaporate into the atmosphere. External dampness, you should also ensure that gutters are kept clear otherwise they may overflow onto the walls causing dampness is controlled with waterproof sealant applied directly to the crack or through holes drilled into the wall. Check for gaps around the base of the wall and replace any old mortar. Clean rain from all paths, roofs and gutters regularly to avoid water penetration