Navitron Renewable Energy and Sustainability Forum

Green Building and Design => Energy Efficiency & Insulation => Topic started by: benseb on June 02, 2019, 12:36:48 PM



Title: Heat loss from very large external doors
Post by: benseb on June 02, 2019, 12:36:48 PM
We have a barn conversion with some nice external barn doors

These were upgraded about 15 years ago when the house was refurbed.

They are double glazed but only have a small airgap - guessing about 4/5mm

While the main door structure is very thick and solid, there  are thin panels in the door which seem to me like one layer of ply.

Weíre looking at ways to improve insulation. All walls and ceiling are insulated which leaves solid floors (difficult to change due to levels) and these doors

There are 6 external doors downstairs including the large barn door

Any ideas on how to improve these or would we never get our money back as I anticipate they will be £££

Thanks
(https://i.postimg.cc/8jMMXKMZ/70914-CBE-2-E31-4014-BD5-D-32-FE669-FD18-C.jpg) (https://postimg.cc/8jMMXKMZ)

(https://i.postimg.cc/87GW2RbN/86029-FFE-0-D7-F-4160-987-C-E1446164-B51-B.jpg) (https://postimg.cc/87GW2RbN)

(https://i.postimg.cc/TLsgFBt4/9-AC57-AB9-8-CCF-4-F03-9430-6-EE870-D5968-E.jpg) (https://postimg.cc/TLsgFBt4)

(https://i.postimg.cc/nM6qkbjs/A7633-C17-F728-438-B-BC01-30-B18-D0-FBFF2.jpg) (https://postimg.cc/nM6qkbjs)


Title: Re: Heat loss from very large external doors
Post by: Bodidly on June 02, 2019, 12:41:37 PM
We have similar doors in our barn. All I can say is we get terrible condensation on the 15mm thick T&G but none on the thick frames. I am intending to put some insulation over the T&G and cover with a painted ply facing that will sit just within the frame but it's still on the "to do list"  whistle


Title: Re: Heat loss from very large external doors
Post by: benseb on June 02, 2019, 01:00:07 PM
Yes Iíd been thinking of something similar actually. We donít get any condensation in the house but they are noticeably cold to the touch

Iím guessing loose wool insulation would be best to really pack into the space?



Title: Re: Heat loss from very large external doors
Post by: Countrypaul on June 02, 2019, 01:21:43 PM
If the insulation would cause the dew point to move onto the wood and you have any exchange of air then you could cause condensation on the wood so any insulation that could absorb water might become a problem. It might cause the insulation to perform badly and also cause the wood to be permanantly wet leading to premature rot.

I think Biff uses a large shet of insulation in front of his door(s) during winter that makes a significant difference. Not sure if the insulation is decorated in any way though.


Title: Re: Heat loss from very large external doors
Post by: Bodidly on June 02, 2019, 02:09:25 PM
Yes Iíd been thinking of something similar actually. We donít get any condensation in the house but they are noticeably cold to the touch

Iím guessing loose wool insulation would be best to really pack into the space?



I was going to use some Celotex. Probably glue it back to the T&G and glue ply too that. Sealed around the edge to avoid some of the problems Paul mentions


Title: Re: Heat loss from very large external doors
Post by: wookey on June 03, 2019, 01:31:56 AM
I got a 120mm thick very low-U custom double door made by a carpenter for £1000. It's essentially encapsuating 100mm of PUR in a doorframe. That's a standard garage-door width+height. So given your need for glazing and a bigger door I guess you'd be looking at a couple of grand for a one-off. But that would be really well insulated. I forget exactly what U-value I got overall but it was under 0.25 IIRC. The airtightness/seal detailing was not as good as it should have been and I'd change that if doing it again.

I'd try asking someone like Green Building Store or Muster Joinery to quote for a replacement. GBS do 78 or 98mm profiles which are U=0.78 and U=0.58 respectively IIRC.


Title: Re: Heat loss from very large external doors
Post by: Barrie on June 03, 2019, 10:44:12 AM
Your glazing may be something like this http://www.slimliteglass.co.uk/slimlite-ultra-clear-self-cleaning-double-glazed-units/slimlite-double-glazed-units.html (http://www.slimliteglass.co.uk/slimlite-ultra-clear-self-cleaning-double-glazed-units/slimlite-double-glazed-units.html)

Pilkington and others have introduced similar products since Slimlite was first featured on Grand Designs.