Where is the draught comming from

[jfc]

My kitchen extension is freezing and there is a draught comming into the front room . The kitchen has a warm roof and 50 mm insulation under the floor with insulation on top and wood flooring . The two roof lights have temporary twin wall plastic in them but are sealed and i can feel no draughts from them . The back doors are brush sealed and have 3mm temp glass in them . I can only think its the cold glass and the cold air is dropping to the floor and then getting sucked into the front room and out the chimney Any other ideas ?

[Head clansman]

Hi jfc
any wall wents open ? is the door sealed at bottom also ? temporaliy seal class with poly see if that helps . hc ps any wall cavity insulation fitted .hc

[jfc]

Walls are solid block with vapour seal and foil backed plaster board . The whole extention was built to current regs to make it warm .... and its not

[old]

Any other ideas ?
It needs heating

[mrgrimsdale]

However well insulated it doesn't take much in the way of tiny gaps, cracks etc, to bypass it altogether. In my last place we went around everywhere with decorators mastic. Not just door and windows but also top and bottom of skirtings, even hair line cracks in the plaster and sockets and light fittings.

[Telos]

Jan 6, 2009 9:03:32 GMT jfc said:

[snip]... I can only think its the cold glass and the cold air is dropping to the floor and then getting sucked into the front room and out the chimney Any other ideas ?

Correct answer!

Most draughts are in fact caused by conditions like this and have nothing whatsoever to do with an actual "leak" of outside air "blowing" into the building. Air circulation due to a temperature gradient, where the cold air sinks, is the most common cause of what most call a "draught". Doesn't even need to be exiting via the chimney to cause what can be felt as a draught.

[chippy]

Do a smoke test. The smoke from an extinguished candle lasts long enough to get some idea which way the draught is moving from/to.

[jfc]

There is a radiator in there all be it a fancy one rather than one that will heat the room But it was free
I think it has to be the single glazing but i'm amazed by how cold the draught is and my cat thinks its a great game to open the door every time i close it I think i'll fit a door closer on it ;D

[Head clansman]

hi jfc

you say it's built to current regs OK , is the extension an add on to the house or is it inside the house main frame work have you got central heating if so did you extend the heating into the extension ?.

If you did this did you resize the boiler to cope with the extra load for the extra heat required to heat the extension sizing the radiator required would depend on the type of materials used to be able to resize the boiler to it new correct bht level required so its not pissing into the wind if you know what i mean . hc

[mrgrimsdale]

Jan 6, 2009 12:11:08 GMT Telos said:

Jan 6, 2009 9:03:32 GMT jfc said:

[snip]... I can only think its the cold glass and the cold air is dropping to the floor and then getting sucked into the front room and out the chimney Any other ideas ?

Correct answer!

Most draughts are in fact caused by conditions like this and have nothing whatsoever to do with an actual "leak" of outside air "blowing" into the building.

Unless there is a leak into the building - which is pretty common in my experience, even with new build.
Had an attic once with 6"insulation which the builder had conveniently ventilated with a gap at the eaves. It kept warm when there was no wind but cooled instantly at the slightest breeze.
With old buildings you can get porous stone walls due to settlement and dropping out mortar.

Mind you, there's no wind (up here anyway) so you are probably right!

[jfc]

Yes the boiler is up to it and the new regs dont give ventelation to the roof void so no leak there . Its an add on extention . I'm sure its the glass , do you think putting poly over the inside or out side will stop the glass getting cold ?

[Telos]

Jan 6, 2009 14:12:39 GMT jfc said:

[snip]... I'm sure its the glass , do you think putting poly over the inside or out side will stop the glass getting cold ?

Err, yes. It's called double glazing ;D

A cheap, temporary, but very effective solution is bubble wrap! Can't see through it, but it's very simple to fit for a week or so.

Slightly more permanent solution (before you upgrade to double glazing in the Spring ) is to fit a sheet of acrylic 'glass' in a simple frame as some cheap secondary glazing. I did the same to my kitchen, worked a treat. In fact the temporary solution was so good, it lasted a year before I changed the window

[mrgrimsdale]

Or clingfilm. If the frame profiles are right you can just stretch it across and it sticks itself. And you can see through it. Its not the film its the air gap.

[jfc]

Twin wall perspex now screwed to the out side ;D What annoys me is the rest of the house is single glazed and built in the 30s and gets lovely and warm but the new kitchen thats supposed to be super effeciant is freezing

[engineerone]

having not seen it since you were building the units jason, i wonder, have you got doors between the living room and the kitchen yet, and i can't remember whether there is another entrance alongside the stairs

are you sure that the doors to the garden and your workshop are properly sealed, although they should be

i seem to remember that you were venting various items outside, like the tumble dryer, are you sure they are sealed properly??

what is always surprising is how a really small space can create some mother of a breeze flowing through.

is there a door between the stairs and the living room. can you close that and see where else the draught is??

now you know what us old buggers begin to feel ;D

paul

[jfc]

Hmmm good point ! The tumble dryer vent and extractor hood are both just holes ( no cover plates yet ) That would be two points of a draught i will sort those first thing tomorrow .

There are doors between the front room and kitchen and a net , thats how i know the draught is comming from the kitchen as its blowing the net .

[nickw]

If you go Jacob's cling film route, attach it to the frame with some double sided tape, then go over it with a hairdryer once its up. This will cause the film to stretch taut.

[jfc]

It was comming from the tumble dryer outlet . I took it apart a while ago and remember thinking that it was odd the vent was just open in the bottom void of the machine . When Paul mentioned it it clicked and i checked it with my hand and there it was ! Vent now stuffed with news paper until i buy a cover . I never thought of checking the tumble dryer for draughts .

[engineerone]

always a good idea to look for the holes ;D

at least we all may not be so complacent that we have thought about everything in the future

saved a few quid last night then mate

paul

[Telos]

Doh! I kinda expect a hole in the wall will have slightly more effect than the cold off of single glazing

At least you didn't start fitting double glazing before you noticed!

[jake]

The next thing to check is that you haven't left the windows open.

[jfc]

No chance of that , i havnt made them yet ;D