Damp and Mould on Walls: The Definitive Guide

Rising damp is moisture present in your walls, as a result of water in the ground underneath. Whatever form it takes, damp is a serious matter, and can have far-reaching effects not only on the structural integrity of your home, but your family’s overall health as well.

When there is dampness on your walls, the thermal efficiency of your home is greatly reduced. So, how do you stop damp on external walls for good?

To answer this question, first need to explain the topic of rising damp in more detail, including: the causes, the signs, and lastly, what you can you do to prevent it…

What is Rising Damp?

The simplest way to explain rising damp is water which rises up the wall of a building, in the same way that oil rises up through the wick of a lamp. Bricks and mortar can be very porous, and the water can rise through their many fine capillaries.

Now, while penetrating damp is the most common form of damp, you should also protect yourself from rising damp as well. And some insulation materials offer a two in one solution to both problems. But more on that later.

Water travels upwards, as a result of capillary action. Capillary action is when water is sucked through a small opening. The water usually stops rising at a height where gravity counteracts the upwards force. This is usually a height of 1.2m, but in some instances, it can go even higher.

What Are The Causes?

One of the main reasons why rising damp occurs is due to the lack of a damp proof course. Even when the damp proof course is installed, faulty installation will still lead to rising damp.

What is a damp proof course? It is a waterproof layer in your wall, or in both walls if you have a cavity wall as well. The damp proof course is usually installed six inches from the outside ground on the external walls.

In some cases, the DPC might function well, but the DPC might be breached. That is when something attached to your walls allows water to travel around the damp proof course. For example, an outside structure, like steps attached above the DPC.

Another cause for rising damp is debris present in the cavity wall. The debris bridges the damp proof course, and allows water to travel around, and into the walls.

Sometimes, the damp stems from another source altogether that you may not be initially aware of. In this instance, your best plan-of-attack is to list potential sources one by one, and eliminate them one by one as you conduct a more detailed investigation of the walls.

Damp and Mould:Telltale Signs

One of the common signs of rising damp is a tide line of yellowish or brownish staining, in the lower area of your walls, just above the skirting board.

You might also notice white and fluffy deposits in the plaster. That is the salt debris we talked about previously.

When damp evaporates from your walls, it leaves a salt deposit behind. This is as clear signal that you have a problem that needs addressing asap.

Damp and Mould: How To Treat It

The first step you need to take is to identify the problem. As mentioned previously, you cannot deal with the effects without first finding the cause.

Some people opt for a quick fix, which is repointing, or painting over the damp. But that is just a temporary solution to the problem. Don’t be deceived: You haven’t solved your dampness problem long-term-you’ve just masked it.

The best way to treat the problem is to install a damp proof course, and/or external wall insulation.

How External Wall Insulation Helps With Damp

External wall insulation is one of the best proven ways to prevent condensation and damp problems. The insulation will form a blanket around your house, and, consequently, improving your comfort inside.

Insulating the external walls of a home has a number of benefits. In addition to decreasing damp, external wall insulation makes sure that your cold walls are not cold anymore, as the insulation will keep them warm.

Insulating the external walls of a home allows your home to retain more thermal mass, keeping the heat stored in the fabric of the walls, and released back when the heating is turned down. The result? A far more efficient heating or cooling system, and refreshing reduction in bills.

The question many ask is how external wall insulation helps stop damp from penetrating through the brickwork, to the interior space inside? Now, while external walls insulation will prevent future problems, it won’t mask the existing problems of water penetration.

The good news is that there are simple solutions to fix such problems. Here’s a few suggestions to get you started.

Exterior Wall Insulation: Your All-In-One Solution

The solution we offer is designed to insulate bricks and porous building materials. Suitable for concrete, bricks, and other types of surface, the wall insulation will protect your home from rain, oil, dirt, algae, pollution, and other potential problems.

So what’s the solution? Put simply, a wall insulation that chemically bonds to the surface, penetrating up to 17mm deep, and creating an invisible insulation barrier.

This barrier reduces water absorption by 95% and more, all while creating a home that breathes at the same time. Remember earlier we talked about non-breathing walls, and how they enhance the effects of damp. This insulation solution resolves this with immediate effect.

The product we offer is a great insulator, enabling your masonry to breathe, and permeable to water vapour. As a result, the thermal conductivity and insulation properties of your home are vastly improved.

To put this into perspective, 5% of damp in cavity wall insulation will lower the thermal resistance of your home by up to 50%. And the best part is, the solution is self-cleaning, as dirt particles cannot remain attached to the brickwork. They simply flow off of the surface with rainfall.

Tests have shown that in practice, Home Logic Wall Insulation exhibits top-quality hydrothermal performance on concrete, sandstone, brick, and mortar.

External Wall Insulation: The Preliminary Process

We mentioned previously that while wall insulation will prevent damp on external walls in the future, it won’t solve the existing problem. Well, this solution does just that. And it all comes down to the preliminary cleaning and priming process, which includes washing and repairing of the walls.

The installation process starts with an inspection, performed by a certified team, that will look at the outside walls of your property. They will identify problems that are there, and how to solve them.

The next step is power wash all areas at high pressure. The washing process removes accumulated dirt, stains, loosely adhered paint, mould, and much more.

The third step is another cleaning process, removing any moss and/or algae if found. The team will use fungicidal agents that kill off spores and prevent their re-occurrence.

Now that the property is cleaned, it is time to repair cracks on the walls of your home. Removal of loose debris follows, and then the team will use quality filler to repair damage, and create a uniform surface. The team will also repair render.

All areas of blown and damaged render are removed, with the team of contractors then re-rendering the surface to match the existing one.

What follows is bagging and masking. Bagging is a process where SBR/Unibond bag coat is applied to the surface, to provide additional stabilisation. Masking, on the other hand, is a process that allows the team to cover doors, windows, and other areas that are not to be sprayed with tape to prevent overspray.

At the very end of the installation process, the team will apply a specialist primer coat to wall surface. The primer coat ensures an excellent bond to the substrate. The coating application follows.

After the walls are prepared, the team will spray long life protective wall coating that will prevent rising damp in external walls. There are a wide variety of colours and textures to choose from. Once chosen, the team uses industrial machinery, for fast application of the wall coating.

Now that your walls are coated, the team cleans up the site, and lets you enjoy your home that is now insulated and protected from damp.