Garage/workshop door construction - insulated/glazed

[matthew]

I'm planning a new hinged garage/workshop door to replace the ageing up+over one - I see some good tips on this recent thread but my specs are a little different:

• 2 x 2000h x 1100w doors
• Insulated (to be workable in winter and help with noise)
• Part glazed (need some natural light)
• Secure (integral garage so should be as secure as the front door)

The aesthetic will probably be something modern, using cedar strip cladding (eg Google Images) to match a previous garden project. My initial rough plan is:

• Oak frame with fitted weatherstrip
• Hollow timber door frames - made from maybe 70mm wide timber (thickness TBC)
• Glazed section probably standard 28mm sealed units
• Voids (of unglazed part) filled with insulation
• Both sides skinned with ply (which should make it quite rigid)
• Cedar cladding applied to front
• Multipoint locking mechanism

Not having done something like this, I'm just pondering some specifics of the above; eg:

• Given it's part glazed, what sort of thickness of insulation does it make sense to use? I was thinking eg 35mm celotex - worth going thicker? Or rockwool instead?
• I'm thinking of 9mm ply either side (nailed or screwed in) - I use lots of birch ply for interior stuff - any more suitable (or cheaper?) choice?
• What kind of hinges would work well? I don't really want external gate-type hinges, since thy seem easily pryable - standard butt hinges? Or worth forking out for fancy Soss hinges? I haven't yet got an idea of how much they will weigh.

Etc - any suggestions/advice much appreciated! Especially as this is kind of a trial run for a matching front door!

 

[Steve Maskery]

They are not the style you are looking for, but this thread might give you some pointers of what difficulties you might encounter.
post1067733.html#p1067733

 

[MikeG.]

Celotex, yes, fibreglass no. 35mm is generous in doors. I would suggest having only sheet of ply built into the door. Its job is prevent the door dropping out of square, and one sheet is plenty for that. Pay attention to the seals and gaps, which contribute more to the heat loss than anything going through the door itself.

 

[matthew]

They are not the style you are looking for, but this thread might give you some pointers of what difficulties you might encounter.
post1067733.html#p1067733

Many thanks for the link - some really useful progress pics there. I insulated my current metal door with polystyrene and found, like you, that I don't really want to do that again hence thinking Celotex or something similar.

Actually, my plan is a bit closer conceptually to your temporary doors - I am hoping the ply will keep it square without diagonals as you have added to your (very smart!) new one. Hipster aesthetic of OSB aside, did they hold up well? Do you feel the hinges are secure?

 

[matthew]

Celotex, yes, fibreglass no. 35mm is generous in doors. I would suggest having only sheet of ply built into the door. Its job is prevent the door dropping out of square, and one sheet is plenty for that. Pay attention to the seals and gaps, which contribute more to the heat loss than anything going through the door itself.

Many thanks for the tips - I figured 35mm would be enough. I was planning 2 sheets of ply not necessarily structurally, but just to have something to contain the insulation in?

Noted about the seals - I did my best with the current metal one but it's a losing battle! For the new one I'm planning fitted weather strips (Schlegel?) with probably a brush along the bottom (with as small a gap as possible) so hopefully it should be a lot less drafty.

 

[Steve Maskery]

Actually, my plan is a bit closer conceptually to your temporary doors - I am hoping the ply will keep it square without diagonals as you have added to your (very smart!) new one. Hipster aesthetic of OSB aside, did they hold up well? Do you feel the hinges are secure?

Hinges were very secure, yes, but the doors did sag a bit. I think it was because the OSB was screwed and glued on. The glue crept a bit. Had the OSB been let inside the rails and stiles, rather than planted on top, I think there would have been zero sagging. I think, if I understand Mike correctly, that is what he is suggesting.