DIY Doctor UK DIY Forums

Hi,

I'm replacing my old unsleeved airbricks with sleeved ones to try to improve ventilation to help with damp. I'm placing three underfloor and one (double one) at just below ceiling height.

I've read up on it a fair bit and the consensus seems to be that it is within my basic diy capabilities and overkill to hire a pro for this job.

Since the underfloor ones are below the level of the dpm i don't think I need to also retrofit cavity trays above them.

My problem is that the sleeves are supposed to angle downwards from inner to outer leaf to guide any water that gets on them to the outer wall to evaporate off over time. However the bricks do not line up in such a way as to achieve this and the sleeve would be lower on the inside - a definite no no! The resulting holes for the airbricks are only an inch or so out of alignment but too much to get the sleeve to slope the correct way.

What can I do about this? Is there a diy solution? Is it ok to cut into the bricks so that I can get space to slope the sleeve the right way or would this weaken them? Many thanks for any advice.

the airbrick sleeves don't need to be situated on a angle, Any moisture will be dried out with the airflow. You can cut back the bricks to align the sleeve with the airbrick. You don't need to install a cavity tray.
If the airbrick sleeve does not line up with the airbrick and you need the sleeve to be lower, you can buy a periscope plastic sleeve that is designed for this type of job.

Hi, I was told that it is very important. Its not about the moisture in the sleeves but about any moisture inside the cavity that will drop into the top of the outside (ie the "roof") of the sleeves (or any other penetrations above dpm for that matter). It is this water that must be guided to the outer leaf of the wall so that it can evaporate to the outside and not wet the inner leaf of the wall and travel inwards causing problems.

Under the floor is fine, I can understand the logic, that moisture could travel across, then you need to fit a cavity tray over it for piece of mind