Garage roof eves - what are my options?

[Monkey Mark]

Morning all, bloody cold here today!

I was reading another thread on heating a garage workshop (https://www.ukworkshop.co.uk/forums/heating-the-workshop-t100845.html) and it seamed to be well timed as last night I was stood in my garage, which I (try) to use as a workshop, thinking that it's way too drafty.
It has a pitched roof so intend to stuff some insulation between the rafters and maybe board over it. But then I noticed, I hadn't really thought of this before, that there is nothing covering the eves outside. I think eves is the right term? Basically there is no soffit. I guess as it's a garage this wasn't necessary.
If i was to box in the eves, do I need to keep some ventilation there as would be in a loft? Is there anything else I need to consider? Or can I just box the lot in so it doesn't feel like I'm stood in a wind tunnel or allow enough moisture it to allow my limited tools to already be showing signs of rust.

Cheers Mark

 

[skipdiver]

Can't see why there would be no soffit.

 

[Monkey Mark]

Can't see why there would be no soffit.

No idea why, there just isn't one. There's a facia board for the guttering to be attached to, but no soffit.

 

[skipdiver]

Then i would fit one. There are all manner of ways to put ventilation in them but penny vents are quick, simple and cheap. However the need for vents has been supplanted by breathable membranes nowadays. Whether it needs ventilation is down to what you propose to do and what sort of roofing felt is fitted.

 

[sunnybob]

Pedantic I know, but they are eaves.
If you are going to fit a false ceiling at a lower level, then you dont need to do anything.

 

[Monkey Mark]

Pedantic I know, but they are eaves.
If you are going to fit a false ceiling at a lower level, then you dont need to do anything.

That's not pedantic, that's correct and I'm always happy to be put on the right track. I did say i wasn't sure what they were called. :mrgreen:

As for the ceiling, I'm not sure yet. I would like to, again mainly for a little better insulation, but that will come down to both cost and effort as I'd have to alter a good bit the cabling and pipework that currently runs on both the top and bottom of the garage rafters. Not hard I know, just don't have the time right now. though it will most likely be done at some point in the future.
If the rafters had been a little beefier I'd have used the space for storage and boarded it all ages ago, but I don't think it would take much load so never bothered as of yet, though it could be used for small/light items I guess.

 

[sunnybob]

False ceiling is the most cost effective way of saving heat.
Heat rises and cold falls, so panelling the walls with out doing the ceiling is just a waste of money.
If you havent already used it for storage, then you dont need to.
You would only need to alter any wiring switches or sockets to be below the new ceiling height, everything else can stay where it is.
Even thin ply nailed across the rafters will greatly reduce heat loss. Put some rockwool on top as you screw it in place to make it very homely.
As a by product, there will be a lot less fine dust in the room as well.

 

[skipdiver]

I'm about to do mine in the next month (he says hopefully) and am going to insulate and board the rafters, so i can use the roof space for storage. My workshop currently has no soffits either as i never got round to finishing it before i got very busy. I also wished i had insulated and boarded it before i filled it up with tools, machinery and stuff as it is now going to be one hell of a job moving stuff around and doing it in sections. When it was nice and warm in the summer, i kept saying to myself, " I'll do it next week, next month" but of course i didn't and it's getting pretty cold in there now. Work has slowed down a bit now though, so i just need to get on with it. I reckon that if i order all the boards and insulation, i will have to get it done as i have nowhere else to store them other than the workshop and i won't be able to do anything in there until i have them all fixed and out of the way.

 

[Monkey Mark]

False ceiling is the most cost effective way of saving heat.

You would only need to alter any wiring switches or sockets to be below the new ceiling height, everything else can stay where it is.
Even thin ply nailed across the rafters will greatly reduce heat loss. Put some rockwool on top as you screw it in place to make it very homely.
As a by product, there will be a lot less fine dust in the room as well.

I'd have to move/alter some as for some reason some of the cabling for things like the combi boiler that were a later addition has been run along the underside of the rafters, but it's all easy work.

 

[beech1948]

MonkeyMark,

2 yrs ago i faced the same problems. Single skin double garage, felted roof, no insulation. My solution was as follows.

1) Waterproof the walls to prevent ingress of driven rain. I used a Thompsons product which I painted on two coats outside. Repeated it this years for 2 coats. It dries clear, is a waxy water impenetrable layer. It lasts quite well but 5yrs is maybe a limit so afew repeats will be needed.

2) I insulated the walls with two layers of 50mm 8x4' sheet insulation. First layer was put on via a 2x2" timber at the base and at the top laid horizontally. The insulation sheet was laid in between these with dot&dab adhesive. I was able to cut out runs for electrics and switch boxes. Second layer was laid between vertical 2x2" timber which was nailed to the underlayer horizontal timbers. This worked well and gave me 4" of good quality insulation from Seconds and Co. 2" sheet insulation is much cheaper than solid 4" stuff.

3) I sealed around the joints from walls to roof with cans of foam from Screwfix

4) The roof was recovered with metal sheets, with alayer of Tyvec underneath. I then laid in 4" of insulation where the 8x4@ sheets were cut into strips about 18" wide ( old standards) and placed along the joists held in place by wire and small nails. This went quite quickly.

5) Covered the ceiling with 11mm OSB and tyhe walls with 18mm OSB 3. Painted it all white.

Very satisfied with this approach seems to work well. Now considering a wood stove to replace the oil filled rad.