Garage Doors (insulated)

[MitreKnown]

Hi everyone, excited to join. I'm not very experienced, but have enough tools to get myself into trouble.

I want to make some garage doors for the garage workshop I am building to take my woodworking further. I want them to be insulated and look traditional (garage workshop will be timber clad with brick plinth and plain clay tiles, when finished. Part of a new house build). The openings are approximately 8' wide and 7' high, so would each be split into two doors. I was thinking along the lines of the following design:

• 9mm (12mm better?) marine plywood exterior (ideally v-grooved vertically)
• 3x2 treated CLS timber 'skeleton' frame with 40mm Celotex in. Two vertical stiles, three horizontal rails/ledgers and two angled braces.
• 9mm marine plywood interior
• Aluminium or galvanised 70x50x1 mm u-channel along the bottom edge with brush screwed on inside
• 57mm height softwood door drip along bottom edge exterior
• Screwed and glued with stainless steel cuntersunk 4mm dia screws with woodfiller over (or could I screw from the inside without penetrating through the exterior plywood)
• 3x4 treated CLS wooden frame with 3x large butt hinges per door
• Painted in something like Dulux Weathershield
• Possibly with a window along the top if I get adventurous / over confident

Does that recipe sound like a good idea? I think the plywood would help with sag (handle edge dropping relative to hinge edge), but would this be too flappy?

Would it make for a reasonably secure door? I could add a 1mm sheet of glavanised steel between the exterior marine plywood and the doors 'skeleton' frame, but that would add quite a bit of weight (+20kg per door).

I'm sure I could buy better doors, but what's the fun in that.

 

[TheTiddles]

I’d probably build the same way, not sure if that’s right though. You don’t necessarily need marine ply, just good external. The groves will be a fiddle but can be done and they will take a chunk of the strength out the sheet so maybe thicker for the face that’s grooved.

Adding sheet steel… the weak-point is usually the lock and hinges so if they’re stronger than cutting through the door yes, but then I’d make the whole door from steel and face with wood.

think about how the water runs off it, if your aluminium channel catches it you are creating a fast rotting problem

 

[MitreKnown]

The groves will be a fiddle but can be done and they will take a chunk of the strength out the sheet so maybe thicker for the face that’s grooved.

Adding sheet steel… the weak-point is usually the lock and hinges so if they’re stronger than cutting through the door yes, but then I’d make the whole door from steel and face with wood.

think about how the water runs off it, if your aluminium channel catches it you are creating a fast rotting problem

I was thinking I could set up my tracksaw to cut to around 1-2mm depth and make the grooves that way. It's a bit high stakes as I'd need to make 11 grooves per 8x4 so little room for error.

I can't weld and don't know where I could get a reasonably priced steel door carcass to work on.

I was hoping the timber drip feature could cover all the way along, but that could create an issue for opening. I may be best off dropping the u-channel.

Cost wise, I expect this would run to about:

• 2no. 8x4 12mm plywood £30 - £90
• 24m 3x2 C24 treated £30
• 2no. 8x4 40mm Celotex £40
• 2no. 8x4 9mm plywood £25 - £75
• 8m 3x4 C24 treated £20
• Drip moulding (pine) £12
• Hardware £100 guestimate
• Paint £20
• Fixings and glue £10

TOTAL: £290 - 390 per pair

I think that's quite cheap compared to what's out there on the market.

 

[Richard_C]

Can't really help with construction but a couple of thoughts. I use half a double garage as a workshop, un insulated basic metal up and over doors. Putting a draught sealing strip along the bottom made a huge difference to comfort with those easterly winds blowing off the fens and rushing in at ankle height., so in your design do think carefully about how the doors will fit the frame and floor and how to keep the wind out. Brush might be OK, flexi rubber seals might be better.

If your grooving isn't perfect it will show and there is no going back. I wonder if slim beads fixed to the front mightn't give a similar visual effect - you will need lots though. You can (or could) also buy ready-grooved decorative plywood (not T&G) but I'm not sure if its available for exterior use. (or ring Dulux and ask about striped paint?)

On costings, price and availability of sheet materials and wood is shooting up - I think c. 80% up in just a few months as supply and demand don't match up. Maybe check your prices with a local timber yard. I see you are in Cambridge, Huws Grey Ridgeons are good (used to be just Ridgeons, now in a bigger group). Might be worth trying to get an account - I got one when I moved in 25 years ago and they were (then) happy to set one up for a domestic customer and they suggetsed it when I went to place my first order. I bought lots in year 1 and 2, since then very little really but their account prices are significantly better on many products.

 

[RichardG]

I’m no expert but I’ve never had much luck with plywood externally, probably because I don’t keep on top of the painting. The thought of grooving through the lamination would seem to increase the chance of water getting in?

When I’ve made doors like this I’ve always made a traditional tenon jointed frame with diagonal braces and then used vertical vee tongue and groove boards on the outside. Filled in between the frame with insulation and then put a 3mm ply skin on the inside or in many cases just left the insulation showing as it’s on a garage or shed so didn‘t really matter.

If you look at the commercial offerings they are all made this way, probably for a reason? Not saying your idea won’t work but may be worth pricing up the traditional way as well.

 

[MitreKnown]

I’m no expert but I’ve never had much luck with plywood externally, probably because I don’t keep on top of the painting. The thought of grooving through the lamination would seem to increase the chance of water getting in?

When I’ve made doors like this I’ve always made a traditional tenon jointed frame with diagonal braces and then used vertical vee tongue and groove boards on the outside. Filled in between the frame with insulation and then put a 3mm ply skin on the inside or in many cases just left the insulation showing as it’s on a garage or shed so didn‘t really matter.

If you look at the commercial offerings they are all made this way, probably for a reason? Not saying your idea won’t work but may be worth pricing up the traditional way as well.

Thanks RichardG. I do like the look of the vee tongue and groove boards but hoped marine plywood would last better, but perhaps that shows my inexperience. I also like the shear support that a sheet material would give.

 

[RichardG]

The frame is key here and where all the strength comes from. The tenons and cross bracing will make for a very rigid structure. A 5 bar field gate is a good example.

 

[MitreKnown]

The tenons and cross bracing will make for a very rigid structure.

I think the plywood sheet would be at least as good at resisting racking as cross braces.

The greater concern is the weather proofing however. The main concern would be at the bottom. Softwood T&G would fare worse than marine plywood wouldn't it?

 

[minotauruk]

Sorry to bring up an old thread. How did you get on ? I am wanting to build my own garage doors due to massive quotes from garage door companies, so looking for advice. Did you manage the finish the project ?