Several years ago we had a long bathroom split into two (so that one is an ensuite). It's the back of a 1930s house which was extended in the 70s, so part of the exterior wall is solid brick, part blockwork cavity wall.
The builder was cheap, and cut a few corners. Generally it's all been ok - everything is still where it should be and we've had the electrics and accessible plumbing checked and tweaked since.
I've recently replaced both extractor fans with better quieter versions than the builder supplied. In the solid wall section they had core drilled straight through, so a clean enough bare hole came out under the roof eave. When I put the new one in I used a duct and folding grille kit which worked nicely, with a noticeable reduction of wind and spiders coming in.
In the cavity wall / ensuite section they had just badly drilled through the inside block, tiling up to the hole to hide the mess, and lined it up with the original 70s clay airbrick on the outside, so the fan is firing extracted air at the airbrick, which doesn't itself have huge holes. So it seems a lot of the extracted air is just being pushed into the cavity.
Do I need to act on this? It doesn't seem to prevent effective extraction when using the shower, but is it going to cause problems down the line? Ideally I would put a similar duct and grille through a hole in the airbrick, I'm not convinced this could be cut from the inside with the tiling and electrics but it's not going to be at all straight forward getting to the outside of airbrick over a sloping extension roof, and even then, I can imagine it just shattering with a 100mm hole cutter.
The builder was cheap, and cut a few corners. Generally it's all been ok - everything is still where it should be and we've had the electrics and accessible plumbing checked and tweaked since.
I've recently replaced both extractor fans with better quieter versions than the builder supplied. In the solid wall section they had core drilled straight through, so a clean enough bare hole came out under the roof eave. When I put the new one in I used a duct and folding grille kit which worked nicely, with a noticeable reduction of wind and spiders coming in.
In the cavity wall / ensuite section they had just badly drilled through the inside block, tiling up to the hole to hide the mess, and lined it up with the original 70s clay airbrick on the outside, so the fan is firing extracted air at the airbrick, which doesn't itself have huge holes. So it seems a lot of the extracted air is just being pushed into the cavity.
Do I need to act on this? It doesn't seem to prevent effective extraction when using the shower, but is it going to cause problems down the line? Ideally I would put a similar duct and grille through a hole in the airbrick, I'm not convinced this could be cut from the inside with the tiling and electrics but it's not going to be at all straight forward getting to the outside of airbrick over a sloping extension roof, and even then, I can imagine it just shattering with a 100mm hole cutter.
