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.
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?
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 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?
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.