Does cavity wall cause damp inside a property?

Not if its installed correctly!

You’ve probably heard of nightmare stories where cavity wall insulation has been installed and the occupants are up in arms over damp and cold coming into their homes.

You’ve probably heard too that when a house is built it generally has a cavity between the internal and external walls.

So let us explain the causes and various type of damp in houses.

Rising damp is caused when the membrane just above the foundations, at the bottom of the room walls is breached. Once the moisture starts to get into the walls, they become damp and the plaster becomes wet.

The outside walls of a brick house are pointed between bricks with cement. When the mortar between the bricks drys out and comes out, driving rain that hits the walls penetrates through the walls. Its the cavity that actually stops this coming into the house.

Occasionally the cavity is full of debris and it is this that passes the damp from the external wall to the internal one.

Generally if you see damp in a home, check to see if the walls are sodden, the plaster soft and coming away from the wall. If it is this will likely be rising damp, but if the damp is on the inside surface of the walls only and the plaster is generally dry, then the issue is caused by condensation.

So armed with this knowledge you’ll now be able to understand why damp ends up in the home and what to consider when having cavity wall insulation.

So to start with you must ensure the external bricks are well pointed, no gaps in between the bricks for moisture to get through.

When My Energy Grants turns up at your home the very first thing they will do is to check the pointing of your house. This has to be perfect before cavity wall insulation can be installed.

There are stories that we hear of property owners saying that as a result of cavity wall insulation, instead of keeping the cold out they had damp coming in. But if you have poor rendering or pointing on the outside of the property this will cause the penetrating water to soak into certain types of wall insulation like rock wall and then like a sponge penetrate the entire internal walls.

Most property owners that experience damp issues are surprised to find that actually its condensation that is causing the internal damp. The cause of condensation is moisture in the air. The simple truth is that by opening windows, using vents and ensuring a flow of air properties can and do avoid damp.

So remember this, if you’re considering having cavity wall insulation installed by My Energy Grants, if you’re rendering or pointing is not up to scratch, we’ll not install the cavity wall in your home until its sorted. But don’t worry we can help sort it for you if needed. YOu’ll also need to commit to opening windows occasionally using vents after showers, allowing the air to flow around your home in order to not have condensation. Finally if the walls have signs of damp, we’ll check if your damp proof membrane or if the cavity walls are clear first with cameras before we start any work.

So when you next get told that cavity walls causes damp, you’ll now be better informed and tell others about My Energy Grants!