Picture the scene: You know that your masonry is in serious need of an update, but like most things in life, the task facing you seems overwhelming.
Should you chance a D.I.Y attempt, or is it better to leave it to the experts?
Yes, you can always go to the store, buy some products, power wash your outside wall, and try to do it yourself. But if not done properly, damp proofing external walls is useless. In other words, you may be able to pull it off in practice, but long-term, it won’t be nearly as effective as when a contractor installs it correctly.
Damp proofing walls will protect your home from moisture, and any resultant damage from damp. Exterior walls that are made from concrete, bricks, and similar material are porous. In other words, they invite moisture if not untreated. Here’s how the process goes…
Damp Proof External Walls: Key Causes
Before you start thinking about insulation and damp proofing, you need to understand what type of damp you are faced with. There are two main types of damp, rising damp, and penetrating damp.
Check if there is a damp proof course installed in your home. If there is not damp proof course that is properly bridged, you will notice salts on the inside of your walls.
These salts make up a crystallised powder, that appears on plaster if there is no protection against rising damp. The plaster usually requires removing, and a new damp proof course needs to be installed.
Penetrating damp, or condensation, manifests as black mould and spots of mildew. Sometimes, mould is accompanied by musty smell and there is something against the wall. One of the solutions for penetrating damp is better ventilation, but damp proofing external walls is a much more efficient solution.
Should you Do It Yourself?
We mentioned at the beginning of this article that sometimes, damp proofing can be done as a D.I.Y project. But we are highly against it. We recommend you never do it on your own.
The reasons are many, but for starters, damp proofing requires usage of special chemicals. They need to be carefully handled, and they can be dangerous.
Yes, buying a silicon gun and products in tubes might be a cheap solution. But ask yourself, would you really like to do it over and over again until you get it right?
The Problems with Damp
There is a reason why damp proofing external walls is important. Damp and mould can be serious problems, with hazardous implications for your health. The problem occurs when your external walls are exposed to water.
This is usually rain, but it can be from another water source as well. The water can enter your masonry, and travel laterally form the external, to the internal walls. If there are cracks in the bricks, they are letting the water in.
In some cases, if there is a constant flow of rain, your walls might stay damp, and not get the opportunity to dry out. As a result, your home’s thermal conductivity is radically reduced.
Cracks in pointing and brickwork affect the overall water absorbency of your walls. Different areas absorb water differently, with some absorbing more than others. The result is damp patches, due to penetrating damp.
In other instances, some areas are more exposed, or more susceptible, to water, and the result might be a large, damp area appearing. The dampness can spread to the internal walls, resulting in damp patches inside as well.
Damp patches contain salts that have washed out of the brick. They can erupt through the paint, and blow the plaster. Sometimes, damp patches are cold spots on the wall.
As a result, you lose 3 times heat faster than the surrounding wall. Cold spots allow even more moisture from your internal air to form condensation. In the spirit of the “rich are getting richer” your damp walls are getting damper.
As for damage to the external walls, when water gets into the brickwork, cracks appear. The action, referred to as the ‘freeze-thaw’ effect, allows more water in, gradually making the problem worse with each passing day. And mould can grow on the outside walls as well, further reducing the visual appeal of your home.