Air brick confusion - still!

My house was built circa 1901 and has two chimney breasts. Presumably, each would have originally had an open fire on the ground level and a further one on the first floor (one of which on the ground floor is still in operation). In the attic, these two breasts meet from either side of the house before exiting through the roof.

The fireplace which is still in use exits through one of the four chimney pots.

Having read lots of suggestions, I had decided to place one air brick (well, technically not an airbrick but a bunch of holes drilled through the brick with a vent in front) in the bricked up chimney breast on the ground floor. A second air brick would be placed directly

above it in the attic.

...and now my problem:

...how can I tell whether there is simply one cavity in the chimney breast between the ground floor, first floor and attic meaning placement of the vents is not critical; or two separate cavities meaning that the attic air brick may simply ventilate the first floor flue but not the ground floor if not placed correctly?

I have trawled the Internet for this information but have not been able

to answer my own question...are all chimneys representative of the Santa type - whereby a fat drunk in a red suit can simply drop down a single cavity to deliver presents!

Reply to
nmorson
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If you have four chimney pots, it would be unlikely that you don't have four flues.

Reply to
S Viemeister

Sorry to be a bit of a muppet here but how do I fit air bricks then to ensure the air flows through the height of the house? Can I simply fit them both 20cm in from the left of the chimney breast and assume that will allow movement of air between the floors and the chimney?

Reply to
nonymouse

You just want to put them where the old fireplace would have been, wherever that was. Not necessarily central on the chimney breast if there are several chimneys and back to back like yours. Put it low down, but not as low as the one I've just had to reposition when refurbing a room recently: the old grille was completely occluded by soot and debris which had fallen down the chimney!

David

Reply to
Lobster

And had anything adverse happened as a result of this?

I'm not convinced that providing a means for expensively-heated, warm, moist air to travel to a point where it can reach a cooler surface, probably covered in partly-soluble combustion by-products from years before, on which it may deposit some of that moisture, is entirely a Good Thing.

If you can ventilate the stack from the outside, or even from under a suspended floor, then it may be a different matter, but otherwise I'd just consider capping the relevant pot with a vented cap.

Reply to
Autolycus

Put it low

... i was going to place them just above skirting board level.

...no can do...exterior wall ajoins neighbours garage

but otherwise I'd

...i had thought of taking no action other than capping. However, many houses I've seen where the old fireplace has been bricked up seem to have employed an air brick at some point.

I'm not sure what you mean by back to back? I was hoping to avoid placing an air brick on the first floor. Also, the problem still remains with the air brick in the attic; potentially there are two channels behind it - would that mean two air bricks are required and then a degree of guess work when fitting to ensure that they each perforate one of the channels behind?

Reply to
nonymouse

I would put a vent in the wall where the fireplace opening used to be, and then put a ventilated cap on the chimney pot.

Don't faff around putting air bricks in the loft.

Reply to
zikkimalambo

You either fit one air brick per flue, or you knock a gap between the flues, so that one air brick will cover both. It is better to ventilate to the outside than to the inside of the house, as it looks neater and is more energy efficient.

Christian.

Reply to
Christian McArdle

Thanks Christian. Ideally I would like to fit one air brick per flue but finding exactly where the flues run when the chimney breast is 5ft across isn't easy.

Thanks to all who posted. Have decided to fit one on the ground floor and one on the first floor fairly central on the chimney breast (and hope for the best!)

Reply to
nonymouse

There is a bit of damp on the chimney breast at ceiling level, which may or may not be penetrating rather than due to damp from within

In my case the chimney's on a party wall, but otherwise I'd agree: but under the suspended floor? That would mean excavating out the fireplace, and there'd still be the falling-debris issue I experienced.

David

Reply to
Lobster

You really need to find where the fireplace was; if you have four stacks together then I'd be pretty sure the fireplace in each room will be offset from the centre, so the 'middle' would NOT be the place to go!!

Is there really no evidence as to where the old fireplaces were? Imperfections in the plaster? renewed section of skirting board over the fireplace? Different sounds when tapping the front? Locate any metal lintel using a detector? If you're really stuck, try lifting the floor coverng: I'll bet there wil be evidence of where the hearth was. An bear in mind if you can find where the opening is in room A, then in the adjacent room B the opening will be on the other side of the chimney breast.

David

Reply to
Lobster

You could hang a length of cable or push a metal rod down the chimney from the top and then use a cable/metal detector device to locate it from the outside or inside walls. There are cheap devices on the market that should work, although I don't know if they can detect non-live cable.

Worth a look though.

HTH deano.

Reply to
deano

coverng: I'll bet there wil be evidence of where the hearth was.

BINGO! Found a slab of concrete about the width of the chimney breast in the first floor room.

...bear in mind if you can find where the opening is in room A, then in the adjacent room B the opening will be on the other side of the chimney breast.

...not sure I follow this. The chimney breasts are all at the end of the house on the end wall - two at the front and two at the rear (it's kinda sideways on)

I'd have to be spiderman to attempt this. The house is 35 ft tall and accessing the chimney involves scaffolding - lots of it.

And I thought this would be a fairly simple job - I can't believe it's not as simple as drilling a few holes in the wall!!!!

Reply to
nmorson

Ok, if you can't get onto the roof, then just go into your loft, get to where the chimney stack comes down (probably branches off into two flues) drill a hole into that and feed in a length of electrical cablle. put it in a few feet and then test below the entry hole to see if you can pick it up with a detector, then keep going down with it, testing every now and then to keep track of it.

Reply to
deano

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