Air brick in chimney breast?

[NWMark]

We are getting a damp patch on the plaster on the chimney breast upstairs. starts about 12" up from the floor and is about 18" high

There is a gas fire downstairs still plumbed into the chimney, although it doesnt get used. Upstairs i dont know if there ever was an opening for a fire as it was like this when we moved in and the breast is less deep than the one downstairs, maybe 12"+ downstairs and 6" upstairs.

We have a shared chimney with next door, with 4 pots on, is each pot attached to a separate 'chamber'?? if so im not sure which pots our ours and which are his, they are all open ended, no 'caps' on.

Ive read i need to install an air brick, is it as simple as remove some plaster, take a brick out and replace with an air brick, or is there more to it than that?

Cheers

[ndg]

How old is the house? Is it old enough to have had a fire upstairs?

Anyway most likely scenario, 4 pots = 4 fireplaces, lounge and bedroom for each house probably. The bedroom fireplace has been blocked up and is collecting condensation/rain and that's soaking through.

Normally fireplaces just get boarded up rather than bricked up, so if it's a brick wall I be wondering if there was an old fireplace there at all. Check to see that the the chimney doesn't split from one set of pots in the loft to go to two stacks at the front and rear of the house (as my last 1920's two up two down did).

If after you checked it all out you're convinced that there is a blocked firplace you do need to ventilate the space with a non closable grill. Either an airbrick if it's brick or a screw in grill if it's plasterboard.

If you don't have a fireplace upstairs it could be the gas fire blocking the lower opening allowing condensation to build up in the chimney for downstairs at a bend in the flue.

As with anything in building it's hard to be sure without having a good poke round yourself!

N.

[davidjpowell]

If the gas fire has no separate flue, I would be a little cautious about air bricks until you are certain what is happening, and maybe take advice. I don't now how real the danger of Carbon Monoxide creeping through different chimney's is, but you would not want to learn the hard way.

[NWMark]

Thanks for the replies.

House was built 1930-ish, ill get up into the loft tomorrow and have apoke around.

Think ill remove some of the plaster board and see what is behind there, house has been completely reskimmed and painted before we bought it, so hard to tell what was there in the past.

So if i turn the fire on downstairs, on a cold morning i should in theory see heat coming out of one pot only?

[lonny]

NWMark said:

So if i turn the fire on downstairs, on a cold morning i should in theory see heat coming out of one pot only?

Or get some of those smoke pellet things from/B&Q/screwfix/Gas-supplies shop. The gas fitter who did my fire used these to work out which chimney pot attached to which fire.

[toomuchbeer]

I would have thought in a house from the 1930's, the chimneys would be seperate betweeen ground floor and first floor. Imagine if you would, lighting a lovely fire in the living room on a cold winters evening, and then going to bed, only to find your bedroom full of smoke from the living room fire.

I haven't come across a house that has both fires venting into the same flue. Each one is self contained within the chimney breast, right upto the chimney pots at high level. However, if it's all made of brick, the joints can sometimes weaken and less gases through from one flue to the other. That's why soem developers place new liners up the flue to stop the possibility of gases escaping.

Smoke bomb as previously stated would be the quickest way.