Pre-Cast Flue Problem

westv

A few months ago we moved into a 70s semi. All is well and fine until yesterday when the neighbour was having his gas fire serviced. The gas man used a smoke bomb to check his flue and when he did a small amount of smoke came out of his opening but most came out of ours.
The gas guy said there must be some sort of breach between the two flues (pre-cast) and that he would have to cap off our gas fire and the neighbours fire.
We asked if anything could be done to put things right but he said it was most unlikely. As he was a gas expert and not necessarily a building expert I was wondering if there were any options available that didn't involve huge sums and/or a large amount of disruption.

modsandmockers

The first thing to do is to get into the two roof spaces and conduct a visual check of the layout and condition of the two precast flues.

westv

Gas guy suggested the breach was within the party wall.

macman

I don't see how he can make such a statement without doing an inspection. Until the install is inspected, the cause is not known and the repair cost impossible to guess.

modsandmockers

westv wrote: »

Gas guy suggested the breach was within the party wall.

It's pretty unlikely that both flues would breach in the same place at the same time after 40-50 years of trouble-free service. Sometimes the precast flues morph into lightweight metal tubes as they emerge from the party wall into the roof space. Are the two rooftop outlets under the same ridge tile? Have you tested your own installation? There is quite a lot of exploratory work which you can do yourselves!

westv

macman wrote: »

I don't see how he can make such a statement without doing an inspection. Until the install is inspected, the cause is not known and the repair cost impossible to guess.

Well he did inspect next doors installation.

westv

modsandmockers wrote: »

It's pretty unlikely that both flues would breach in the same place at the same time after 40-50 years of trouble-free service. Sometimes the precast flues morph into lightweight metal tubes as they emerge from the party wall into the roof space. Are the two rooftop outlets under the same ridge tile? Have you tested your own installation? There is quite a lot of exploratory work which you can do yourselves!

I did have a quick look in the loft a month ago and I do seem to remember a metal tube in the loft up to the roof
I'm guessing that perhaps there is a gap between the two flues in the party wall and next doors flue is blocked. That way all the escaping smoke goes up his flue, into ours and out of our outlet (we each have independent outlets)

modsandmockers

westv wrote: »

Well he did inspect next doors installation.

Just to be sure - did the gas fitter's smoke come into your front room, or did it come out of your roof-top flue terminal?

westv

modsandmockers wrote: »

Just to be sure - did the gas fitter's smoke come into your front room, or did it come out of your roof-top flue terminal?

Almost all of the smoke from next door came out of our roof top terminal. None came out into the front room.

modsandmockers

westv wrote: »

I did have a quick look in the loft a month ago and I do seem to remember a metal tube in the loft up to the roof
I'm guessing that perhaps there is a gap between the two flues in the party wall and next doors flue is blocked. That way all the escaping smoke goes up his flue, into ours and out of our outlet (we each have independent outlets)

I seriously suggest you buy a box of smoke pellets and conduct some tests of your own. Flues are notoriously fickle, and so are gas fitters! (oops - did I really say that?) Are the rooftop terminals underneath ridge tiles, or are they plastic tubes with a slotted cap?

westv

modsandmockers wrote: »

I seriously suggest you buy a box of smoke pellets and conduct some tests of your own. Flues are notoriously fickle, and so are gas fitters! (oops - did I really say that?) Are the rooftop terminals underneath ridge tiles, or are they plastic tubes with a slotted cap?

They are underneath ridge tiles but slightly sticking up - if you see what I mean.