draft from this area, cant really

[robpeake]

morning, we had our extension finished a few months back, noticed its very cold even though we have two radiators (bigger than were there before although on one side of the room) the skirting board has not been installed yet but there seems to be a draft from the black (think its the damp proof course) but there arent visible holes or splits but you can feel it against your hand. i put some mastic down where i thought there were a few weeks back but last night with it being quite cold i could feel a constant draft coming though. Im assuming skirting board will resolve the draft if it was affixed to the wall and then caulking along the top of the skirting board.

 

[Ivor Windybottom]

It looks fine. The draughts are probably from the edges, you'll feel it at the bottom as the cold air sinks there.

Get the skirting in and don't worry about it.

Your new room may take a while to warm up, once you get it warm once it will hopefully stay that way. Although if you have the seemingly standard fashion bi-fold doors the size of the front of a car showroom then the bad news is that it will probably always be cold.

 

[robpeake]

lol thanks, no bi fold doors on this extension, a skylight but no draughts from that at all. Perhaps need to bump the heat up as 21deg on the thermostat isnt cutting it

 

[Ivor Windybottom]

It won't make any difference if it's never reaching 21. The thermostat will demand heat if it's below that, it can't demand more forcefully if it's further below its target.

 

[JohnD]

With a suspended wooden floor, cold draughts come up through the gap round the edges of the room. They also carry black dust which marks walls and carpets,

If you can take up the boards, you can pack the gap with mineral wool. The edges against external walls are the worst. Keep airbricks clear.

Otherwise, put something under the skirting. Cork or felt strips, maybe. Expanding foam works but be very careful to keep it off exposed surfaces such as a varnished floor.

 

[JohnD]

a skylight but no draughts from that at all

If the skylight is not sealed, cold air won't come in, but hot air will rise out, causing suction that causes cold air to enter the room below in draughts.

You can use a joss stick to show where air is coming in or going out.

 

[JohnD]

The cold you feel from the wall may not be a draught (I can't see a gap) so it is probably air cooled by the cold wall flowing downwards (a convection current). You can't see it, but it is like a waterfall. A joss stick will show it.

You get the same downward flow of cold air from windows. Hence curtains and blinds reduce heat loss.

 

[robpeake]

With a suspended wooden floor, cold draughts come up through the gap round the edges of the room. They also carry black dust which marks walls and carpets,

If you can take up the boards, you can pack the gap with mineral wool. The edges against external walls are the worst. Keep airbricks clear.

Otherwise, put something under the skirting. Cork or felt strips, maybe. Expanding foam works but be very careful to keep it off exposed surfaces such as a varnished floor.

thankyou for your replies, its a solid concrete floor i cranked up the heating to 22deg last night and the room was alot warmer than previously, plus i had the heating on during the day so the room was not so cold to start off with. was thinking maybe a panel heater on the the other side of the room (electric) just for really cold days

 

[JohnD]

thankyou for your replies, its a solid concrete floor

Then I think the wall must just be cold.

You can get cold air behind plasterboard if there is a gap such as dot and dab, but I can't see one, or inside a cavity wall with holes in it.

If fitting an extra heater, try to put it on the coldest wall, and use a long and low one.