Vent in bedroom wall ( Fill in with foam ) possible

[Sam-1973]

This morning I noticed a small damp patch on the plaster from my upper stair bedroom wall.
I was wondering what could be the cause, so went outside and I noticed that there
is an external vent. So this is the source of the problem.

I removed a small section of the plaster to have a look and its just local dampness to a small section of the plaster.

Inside the bedroom there is another vent, also inside the bedroom there is no boiler etc.
So given where the location, I would prefer not to install a vent on the internal wall. As
there is no need.

I am looking to block this up from inside the house.

My question is, rather than removing the whole vent, could I use waterproof
spray foam to fill in the hole, I was thinking of placing some tinfoil at the far back
of the vent to stop it protruding externally outside. Then could I just plaster or
sand down the foam for internal finishing.

Help on this would be welcomed.

 

[opps]

Any foam that squirts out can be cut back. In time it will become orange and brittle when exposed to sunlight. You will be able to cut it back and fill over the exterior.

Spray the area with water to improve adhesion and accelerate curing times.

 

[Odds]

Is the gap a 6x6?
Maybe consider a nice tile to cover the gap.

*after filling the vent shaft, as suggested.

 

[Sam-1973]

So can keep whole external vent in place and just apply the spray foam directly into the space, image below ?

 

[opps]

yes.

 

[Sam-1973]

Thank you!

 

[opps]

Looking at the image. After you spray, squirt some foam in to the bottom left corner, let it cure slightly. Then spray a bit more on to the semi-cured foam. If you don't, it may drop into what looks like a cavity.

Unless you purchase 360 degree foam, invert the can when spraying.

 

[Sam-1973]

Looking at the image. After you spray, squirt some foam in to the bottom left corner, let it cure slightly. Then spray a bit more on to the semi-cured foam. If you don't, it may drop into what looks like a cavity.

Unless you purchase 360 degree foam, invert the can when spraying.

There is a cavity surrounding the vent, thanks for the tip, very much appreciated!

 

[opps]

Given that you probably don't have a dedicated foam gun and will be using can with a nozzle, I would recommend that you consider buying a can of gun cleaner, or some acetone. Acetone will break down excess foam in the event that it slumps out. The gun cleaner is about £7(?).

When taking a break from using a can of regular foam, stand the can upright and let a little bit of the propellant escape. It will help to keep the nozzle clear. It should buy you 3 or 4 days grace.