Draught from supposedly blocked up fireplace

[dubgem]

My living room has a blocked up fireplace (it was blocked up when I bought the house). There was an air-vent over the blocked-up opening, and now I have a radiator in front of it. The room was always colder than other rooms, I got a chimney cowl put on the chimney pot and that definitely made a difference, but the room is still colder than other rooms and there is a definite ankle-biter draft - there doesn't seem to be a perceptible cold airflow coming from the fireplace, but at the same time I can't find anywhere else it could be coming from.

My question is, would it be a good idea to get the chimney completely capped. I heard somewhere that you should never block up a chimney because you get damp problems, but then somebody else told me it's no problem. Can anybody clarify? If I did get it done would it be expensive? And should I also get the vent in the blocked up fireplace completely blocked (which would entail removing the radiator), or should I leave it in place to stop any damp? Or would it just channel any damp smell into the room?

Feedback appreciated, thanks!

 

[BillK]

The draught is almost certainly going to the fireplace rather than from it. (You could try lighting a candle in front of the vent to see which way the draught is travelling.)

I would NEVER completely block off a flue as you will certainly get problems with condensation, and therefore damp, on the breast.

 

[onq]

The draught is most likely coming from the vent.
I have no experience in completely blocking off flues at the top.
I have seen more than a few fireplaces in older houses that were plastered over.
This was often in rooms that had not other form of ventilation and there were damp problems.
In relation to radiators, the location of choice is under the window to help combat draughts running down the window.

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.

 

[dubgem]

@BillK you may be onto something, I have just spent the evening siliconing half the skirting boards and taping down the net curtains (I only have single glazed windows) and it seems to have made some difference.

@ONQ - I've never really understood the radiators-under-the-window thing. Yes, it makes sense in theory, but surely if you have double glazing there is minimal draft coming from the window, and I don't think I've ever lived in a place that didn't have furniture under the window, which therefore would block any under-radiator and prevent any radiant heat from reaching the room.

Anyway, thank you both for the feedback

 

[huskerdu]

I don't think I've ever lived in a place that didn't have furniture under the window, which therefore would block any under-radiator and prevent any radiant heat from reaching the room.

Anyway, thank you both for the feedback

Good point, except that radiators do not heat a room by radiating heat, despite their name. Heat rises and heats the air above the radiator and natural convection currents transfer this heat around the room. ( Leaving Cert science was a long time ago, I hope I described that correctly)

That is why double radiators and wide radiators are more effective.
Very important not to put a shelf on top of a radiator as you seriously degrade the performance.

 

[dubgem]

Good point, except that radiators do not heat a room by radiating heat, despite their name. Heat rises and heats the air above the radiator and natural convection currents transfer this heat around the room.

And that's a good point too. But surely a radiator on a windowless wall can do that just as well as a radiator under a window? Also, I've always been uneasy about appliances - TVs, etc - being right up against a radiator in case they overheat.

 

[Leo]

Placing radiators under windows is less of an issue now that double glazing provides far superior insulation.

See the MAXIMISING RADIATOR EFFICIENCY section of this page.

Placing electrical appliances near radiators will shorten their life span.
Leo