Removal of flue on Rayburn

moneyistooshorttomention

The Rayburn has been removed from this house (along with all its constituent parts including the flue in the kitchen wall).

This flue seems to have been venting to the outside through a chimney in the roof of the house as far as I can make out.

There is now a large hole in the kitchen wall where the flue was and I am being told its necessary to leave that hole there and just cover with it a ventilation grille (otherwise some damp might occur on that wall at that point).

I don't think this would be the case and its not possible to leave that hole unblocked and just covered by that grille (as its making the kitchen too cold having a hole in the wall like that).

Is it okay to just plaster that hole up and there couldn't ever be a damp problem from having done so anyway or do I have to have the chimney removed from the roof of the house and have it blocked up the top or what?

cynicalgit_2

Historically chimneys provide ventilation for living spaces in addition to expelling combustible gases.
IMHO it is better to retain a measure of ventilation for your chimney, to maintain the fabric of it for the future.
I would be inclined to cover the hole with a sliding plastic vent which can be closed in exceptionally bad weather.
By retaining the chimney future owners may want to add a flue based appliance.

ariba10

If you cap the top outlet of the flue to stop rainwater, there would be no reason to have an opening at the bottom to ventilate it.

moneyistooshorttomention

How big a hole do you think is necessary behind a ventilation grille for venting purposes?

There is a blimmin' great hole there at present and I would imagine that a much smaller/neater hole would do the job. Perhaps a 2" circumference hole would be enough do you think?

moneyistooshorttomention

ariba10 wrote: »

If you cap the top outlet of the flue to stop rainwater, there would be no reason to have an opening at the bottom to ventilate it.

I am googling around wondering about the fact that the chimneys on this house would now appear to be surplus to requirements.

So am wondering whether I should either put rainguard cowls on top of the chimneys or put a chimney cap on them?

Part of my thinking is where would the water likely come from to create damp on the kitchen wall. Would it be likely to head down the chimney if I don't put a suitable cap or cowl on the chimney? or would it be just from the condensation that is likely in a kitchen anyway (courtesy of cooking in it)?

To date I am tending to think that I would need to do a several stage job:
- reduce the size of hole in kitchen wall where Rayburn flue was
- put a sliding air vent cover (hit and miss) over the hole
- put caps on the chimneys at the top

Would that be about what I need to do to best solve my cold air in house problem without creating a damp problem?

cynicalgit_2

Sounds like a good compromise to me, keeping moisture out of the chimney,ventilating the kitchen and maintaining the fabric for possible future use.

muckybutt

From a chimney sweep:

You do need to keep unused chimneys ventilated both top AND bottom to keep a through flow of air into the chimney.
Cap the tops off by all means with proper cowls that have air holes in them, where the fireplace was you should always have some sort of grille installed to allow air flow.

Without the bottom grill you will get condensation build up inside the chimney which would eventually leach through the chimney breast.

Before you get them capped off get the chimneys swept to get rid of any loose soot / crud from inside it, then get the tops capped off and the fireplaces sealed up with the grills installed.

muckybutt

ariba10 wrote: »

If you cap the top outlet of the flue to stop rainwater, there would be no reason to have an opening at the bottom to ventilate it.

Yes there would see post above !

ariba10

muckybutt wrote: »

Yes there would see post above !

No there won't!

Mr_Ted

ariba10 wrote: »

No there won't!

Yes there would as has already been stated unless you want to take the chance of a big black soggy patch on the wall where the damp soot will leech through

muckybutt

ariba10 wrote: »

No there won't!

Here you go Mr Knowitall "You should cap any unused chimneys with a flue ventilator. Flue ventilators can be found on our chimney pot page. The flue ventilator stops rain entry to the chimney but still allows a small amount of air passage for ventilation.
You should block off the bottom of the chimney with a register plate or by closing the baffle at the back of your fireplace if you have one. Some ventilation holes are a good idea so that the chimney is still a ventilated space so consider leaving a small gap or hole somewhere when you block the chimney off."

Taken from a well known and trusted stove seller. Being a chimney sweep I think I know slightly more than you on the subject.