Is Decayed Pointing Causing My Damp Problems?
Last Updated 28 August 2018
Penetrating damp is caused by the ingress of water from the outside of a building to the inside. There are many causes of penetrating damp, and one that we encounter regularly is decayed or poorly installed pointing.
p Poor pointing is one of the easiest causes of penetrating damp to fix, but only if it’s caught early. If you leave it too long, the entire wall can become compromised, putting you not just as risk of penetrating damp but serious structural issues as well.
Why is pointing so important?
Bricks are made from a porous clay, with some bricks more porous than others depending on the materials used and how they are manufactured. All bricks are full of capillaries that will suck up water like a sponge, so brick walls are often coated in a waterproof sealer to prevent water seeping into the bricks.
When pointing is perished, rainwater can seep into the top or sides of the brick where there is no waterproof seal, allowing water to seep into the brick.
In cold weather, water in the bricks will freeze, expand and damage the brick. Frost-damaged bricks can crack or completely shatter. When you see bricks with a rough, eroded surface, it’s usually caused by damage from freeze-thaw.
These damaged bricks will not only lose their waterproof seal, their rough surface slows down and collects water instead of it flowing smoothly away, continuing the cycle of water penetration and damage. Surrounding pointing can crumble away, making the surrounding bricks vulnerable.
This cycle is how just a single cracked or unsealed brick can eventually weaken an entire wall and cause severe penetrating damp.
If we find a brick which has lost its smooth surface, we use a specialist brick cutter to remove the brick and flip it around so that the undamaged surface is facing outwards. This allows you to keep using the same brick stock while doubling the lifespan of the brick.
Of course, you can only do this once, so it’s essential that you keep an eye on the health of your wall and quickly replace and damaged bricks or pointing. It’s much quicker, easier and cheaper to replace one brick than repair a whole wall, not to mention any damage from penetrating damp within your property.
I just got my wall repointed, am I safe?
Only if the correct pointing was used.
Pointing should always be softer than bricks so that any expansion in the bricks or movement in the wall compresses the soft pointing, leaving the bricks undamaged. Think of pointing like the discs between the vertebrae in your spine.
Unfortunately, a lot of builders use cement pointing which is harder than brick. Instead of absorbing force from any movement, it’s sent through the softer bricks, which can crack or shatter. The cement pointing might also pop out of the wall, leaving the bricks exposed.
Cement pointing is also impermeable, so moisture that should breathe out of the bricks through the pointing becomes trapped in the bricks instead, making them even more vulnerable to frost damage and the growth of salt crystals.
It’s easy to spot a wall with cement pointing because the bricks will have eroded more than the pointing, which is the opposite to how a wall is supposed to age.
The mortar we use for pointing is mixed with lime, a soft and porous material that has been used for thousands of years. When it comes to pointing, if it ain’t broke, don’t fix it.
What looks like rising damp might be penetrating damp
When water soaks into a wall, gravity slowly pulls it towards the floor where it settles. To the untrained eye, or to someone trying to sell you an expensive damp-proof course replacement, this can look like rising damp.
However, if an inspection of the exterior wall reveals decayed pointing and cracked bricks, it’s very likely the damp is caused by penetrating damp. Treatments for rising damp in such cases are an attempt to solve a problem that doesn’t exist. The damp will come back, and you’ll have nothing to show for the huge bill left over from the [rising damp]a(href=‘/guides/rising-damp/’) works.
Whatever type of damp you have, it’s important that you have it accurately diagnosed by trained and qualified damp specialists, not rising damp salesmen.
To talk to our friendly customer services team and get in touch with one of our damp specialists, call us now or request your call back today.
How does pointing cause damp problems?
- If pointing is decayed, water creeps around the side and top of the brick and can soak it like a sponge.
- Wet bricks are vulnerable to frost damage, which can shatter a brick and lead to even more water ingress.
- If walls aren’t regularly inspected, a single cracked brick can spread damp and damage to a wide area, leading to expensive repairs.
- Concrete pointing is too solid to allow for normal movement and breathing in the wall, which damages the bricks.
- Pointing should always be made from a lime-mix mortar that is softer and more porous than the surrounding bricks.