Sub floor ventilation problem with one outside wall

Misskerry · Post by **Misskerry** » Thu Jul 15, 2021 11:35 am

I own a studio flat that has problems with sub floor ventilation, as the flat behind was extended 25+ years ago, with a concrete floor blocking the through ventilation. It is causing a damp, musty smell in the flat. I have had floorboards up and it isn't damp by outside wall but does smell damp further in towards concrete floor of neighbour.

Been advised to put a couple of vents under kitchen units to aid air flow but unsure this is the way to go.

Any ideas/suggestions to solve this problem, would be very much appreciated.

Thanks,
Kerry

Neelix · Post by **Neelix** » Thu Jul 15, 2021 7:30 pm

Could you add additional air bricks under your property?

Misskerry · Post by **Misskerry** » Fri Jul 16, 2021 9:13 am

Thanks Neelix. I was told that adding extra airbricks on the one wall wont make a difference to airflow

Someone-Else · Post by **Someone-Else** » Fri Jul 16, 2021 3:08 pm

Can you not add more on a different wall? or even run ducting (Like extractor fans use.) from the "dead" end to say the side or ..............

Neelix · Post by **Neelix** » Fri Jul 16, 2021 4:49 pm

More ventilation has got to be an improvement …

Razor · Post by **Razor** » Sat Jul 17, 2021 6:54 am

If you only have access from one side then you will need some form of mechanical ventilation.

Ideally you would run some 4" soil pipe in from the outside to the far end then tee it off with a leg going either way to split the subfloor space into three equal parts then fit an extractor on the outside to promote airflow.

In reality if you can shove a length of pipe in there even a very low power PC fan would give enough air movement to make a significant difference

Neelix · Post by **Neelix** » Sat Jul 17, 2021 9:14 am

A room with a shut door and 1 window WILL ventilate a room - so adding another air brick must help

Razor · Post by **Razor** » Sat Jul 17, 2021 9:56 am

Neelix wrote: ↑Sat Jul 17, 2021 9:14 am A room with a shut door and 1 window WILL ventilate a room - so adding another air brick must help

Any ventilation helps but that will not ventilate an entire room. That's why mould starts to grow in the corners.

The bigger issues in a house is the amount of things that give off water vapour

ayjay · Post by **ayjay** » Sat Jul 17, 2021 10:29 am

Neelix wrote: ↑Sat Jul 17, 2021 9:14 am A room with a shut door and 1 window WILL ventilate a room - so adding another air brick must help

You always need *cross ventilation* under a floor, nothing else is as effective, just as your room with a closed door and a one open window will ventilate much more effectively with the door open.

Misskerry · Post by **Misskerry** » Sun Jul 18, 2021 4:31 pm

Great, thanks everyone, really appreciate your answers.