Warm Deck Dormer Roof - Is this correct?

ds1980

weve just done our own loft extension. Not read it all but what are building regs doing? We had to leave all works exposed for them to look at?!?!

We have just built a dormer (looks the same from pics) if i remember rightly there had to be 130mm of celotex between the ceiling joists, with a gap between the ply (underside of flat roof) and top of it. Then 25mm celotex underneath the plasterboard.

Looks like you aint got any!

ds1980

[IMG]http://forums.moneysavingexpert.com/<a href="<a href=http://s1279.photobucket.com/user/Martin_Bunn/media/photo2_zps530f13e6.jpg.html&quot; target=_blank rel=nofollow>http://s1279.photobucket.com/user/Martin_Bunn/media/photo2_zps530f13e6.jpg.html"</a&gt; target="_blank"><img src="<a href=http://i1279.photobucket.com/albums/y536/Martin_Bunn/photo2_zps530f13e6.jpg&quot; target=_blank rel=nofollow>http://i1279.photobucket.com/albums/y536/Martin_Bunn/photo2_zps530f13e6.jpg"</a&gt; border="0" alt=" photo photo2_zps530f13e6.jpg"/></a>[/IMG]
like this although the 25mm hasnt been put on yet

System

ds1980 wrote: »

weve just done our own loft extension. Not read it all but what are building regs doing? We had to leave all works exposed for them to look at?!?!

We have just built a dormer (looks the same from pics) if i remember rightly there had to be 130mm of celotex between the ceiling joists, with a gap between the ply (underside of flat roof) and top of it. Then 25mm celotex underneath the plasterboard.

Looks like you aint got any!

completely different roof construction there :money:

ds1980

It's exactly the same ain't it? Ours is cold deck? There's is no deck. Can't see any BI getting on top a flat roof 3 storeys up to inspect a warm dec. ours is lovely and toastie BTW. ;-)

ritesh

Hi,

I have just finished adding a new warm deck roof construction to a garage conversion. The actual make up is correct from the construvtion point. However the warm deck should be enveloped. At the fascia aspect (where joists/deck meet fascia) there should be insulation here to prevent cold bridging. Ideally one would ideally fit a timber frame (18mm) around the joists to fit the fascia boards to give a solid fitting. From you photo it looks like it is void behind this would suggest that air is able to get in thus you are loosing thermal efficiency.

cyclonebri1

Yes as above, the fascia should not be nailed to the ends of the joists, there should be a closing timber across the joist ends prior to the fascia being added.;)

andyuk2005

Yes DS, yours is a cold deck where as mine is a warm deck (just not properly constructed!!)

I have spoken to the directors of the company who built my one, and along with the other problems we've been having they seem pretty shocked at the extent of the bad building quality. I've got them in the dog house but then again I did before and they didn't exactly pull through to make up for it, I'll see how it goes!

Thank you everyone for your help, it really is appreciated!

I am surprised that building control didn't pick any of this up. I was here when they came round but apparently they just had a very quick look inside the room and that was it! What's even more surprising is we had that independent surveyor come round and he missed that too!

ds1980

I'd be going back to BC if I were you what are you paying them for!

cyclonebri1

Andy, can I just ask before you disappear why you or the builder went for a warm deck, it really should be for a good reason as it is likely to be cheaper and insulated to a higher standard if left as a cold void, IE, why heat a space you don't even see let alone use????

ds1980

Ie why not do it like me? ;-)