Blocking air bricks?

[Mudball]

Hi.. we have suspended floors, and have a few air bricks around the house. As I understand, these should not be blocked as they prevent floor joist from rotting.
Then we have a random massive air brick (waist high) outside the kitchen window. Any idea what this can be and is it safe to block this off?
The house can get very draughty and so looking to reduce any redundant entry points. You can almost sense the air move around downstairs when it is windy outside.

(Update).. I managed to get a thin stick thru the holes... it measures about 30cm.. so pretty much runs the depth of an external cavity wall .. can’t see thru the holes. But the stick does not seem to hit a kitchen cabinet on the other side. Maybe there is a plasterboard on the other side.. the kitchen was put up by the DIY owner

 

[Tashyboy]

We had one in an old pit house, it let air into a pantry. It had a door/flap on the inside that could be closed. That had been filled in with clothing and newspapers. We found a pair underpants about 50-60 yrs old and a newspaper going back to the 1930s ?

 

[USER1999]

Do these not provide ventilation for open fireplaces? Or may be wood burning or coal fired boilers? Or Agas?

 

[Mudball]

Do these not provide ventilation for open fireplaces? Or may be wood burning or coal fired boilers? Or Agas?

We had one of those at our old house. It had a fireplace and I am told it is needed to ensure ventilation.

We have a open fireplace in this house too but in a different room (and we have removed it). The challenge with this is that the block opens behind kitchen cabinets the previous owner put in. So no way of knowing if there it opens or not.

 

[jim8flog]

I have one in my kitchen it provided the necessary ventilation for the gas boiler. Which was open flued. No longer needed as I have a closed vent system now.
The simple answer is to have a hit and miss ventilator on the inside (ie one you can have open or closed).

If you have any open flued gas installations in the kitchen it must not be blocked off.

 

[Mudball]

I have one in my kitchen it provided the necessary ventilation for the gas boiler. Which was open flued. No longer needed as I have a closed vent system now.
The simple answer is to have a hit and miss ventilator on the inside (ie one you can have open or closed).

If you have any open flued gas installations in the kitchen it must not be blocked off.

Only gas in the kitchen is hob & oven.. the boiler is now in the loft. even when we bought the place, the boiler was in an airing cupboard on the first floor landing

 

[Fade and Die]

Think Tash nailed it straight away it’s for a pantry. We used to have one when we lived in Millwall. Dad knocked it out (it had slate on the shelves to keep the food cool) and put a bit of ply over the hole.
The lower vent looks like it’s below the damp course so will be under the floor to stop damp.

 

[rulefan]

Hi.. we have suspended floors, and have a few air bricks around the house. As I understand, these should not be blocked as they prevent floor joist from rotting.
Then we have a random massive air brick (waist high) outside the kitchen window. Any idea what this can be and is it safe to block this off?
The house can get very draughty and so looking to reduce any redundant entry points. You can almost sense the air move around downstairs when it is windy outside.

(Update).. I managed to get a thin stick thru the holes... it measures about 30cm.. so pretty much runs the depth of an external cavity wall .. can’t see thru the holes. But the stick does not seem to hit a kitchen cabinet on the other side. Maybe there is a plasterboard on the other side.. the kitchen was put up by the DIY owner


View attachment 36029

Don't block vents below the dpc (damp proof course), ie the lower one.
As the other seems to be already blocked and you haven't got an open file or gas boiler in the room, I would suggest you are ok to block it.

Edit: Have you got cavity insulation in the house walls?
Edit 2: Of course gas boilers are already vented.

 

[SocketRocket]

When I had cavity wall insulation they filled up the vent bricks with sealant.

 

[Mudball]

Don't block vents below the dpc (damp proof course), ie the lower one.
As the other seems to be already blocked and you haven't got an open file or gas boiler in the room, I would suggest you are ok to block it.

Edit: Have you got cavity insulation in the house walls?
Edit 2: Of course gas boilers are already vented.

I am told that we have cavity wall insulation... there are holes that shows it has been pumped in. When we replaced some of the front windows, the installer said there is insulation around the windows. However I am not convinced that it is in all walls eg. A part of the top Half of the front has clay tiles.. the room behind it can be very cold.

As SR was saying, we can see some insulation leaking out between some of the bricks in other places, but nothing near this one.

On another note, is there a way we can find if the house has sufficient cavity wall insulation?

 

[jim8flog]

Only gas in the kitchen is hob & oven..

I am not a specialist but those two will be producing carbon monoxide which is why you have ventilation.

 

[Mudball]

I am not a specialist but those two will be producing carbon monoxide which is why you have ventilation.

Hence we have a cooker/chimney hood + a CO alarm .. I may be wrong but I am assuming that is sufficient

 

[Bunkermagnet]

TBH it's impossible to say whether you can block it or not without someone with a modicum of building knowledge just from a picture.
My initial thoughts are it's the neccessary ventillation for a gas appliance/boiler. However, as you say its behind a new kitchens cupbaords, it could also be the air input side for the fridge freezer ventillation if you have an integrated fridge freezer or the like (which need 200cm2 free flow air underneath , up the back and out the top)

 

[Bunkermagnet]

Hence we have a cooker/chimney hood + a CO alarm .. I may be wrong but I am assuming that is sufficient

No, a cooker hood cannot be counted for that purpose

 

[jim8flog]

Hence we have a cooker/chimney hood + a CO alarm .. I may be wrong but I am assuming that is sufficient

No the cooker hood just removes the fumes it is not supplying the ventilation/air flow in my opinion.

 

[Mudball]

TBH it's impossible to say whether you can block it or not without someone with a modicum of building knowledge just from a picture.
My initial thoughts are it's the neccessary ventillation for a gas appliance/boiler. However, as you say its behind a new kitchens cupbaords, it could also be the air input side for the fridge freezer ventillation if you have an integrated fridge freezer or the like (which need 200cm2 free flow air underneath , up the back and out the top)

I agree, it is difficult to say.
BTW, The fridge is on the other side of the kitchen. The wall behind the air brick is just storage units. The cooker/oven is on the next wall and not far from it..

 

[rulefan]

I agree, it is difficult to say.
BTW, The fridge is on the other side of the kitchen. The wall behind the air brick is just storage units. The cooker/oven is on the next wall and not far from it..

Is this ventilation blocked on the inside of the house?

 

[jim8flog]

I agree, it is difficult to say.
BTW, The fridge is on the other side of the kitchen. The wall behind the air brick is just storage units. The cooker/oven is on the next wall and not far from it..

Floor standing kitchen units will have an airgap behind and underneath them which means the air will freely circulate.

If you have plinths under the unit and a gas oven there should be a vent on the plinth to aid air flow

 

[Mudball]

Is this ventilation blocked on the inside of the house?

cant see it as it is behind the kitchen units... but the vent go 300 cm deep

 

[Mudball]

Floor standing kitchen units will have an airgap behind and underneath them which means the air will freely circulate.

If you have plinths under the unit and a gas oven there should be a vent on the plinth to aid air flow

View attachment 36037

tnx/. there is a plinth under all the units.. the one under the cooker/hood can get really draughty. I was assuming that was because the tiles dont go all the way to the wall and there would be holes in the floor board due for all the utilities to come thru..