I’d like to insulate my garage to make it a little more comfortable for winter bike fettling, it’s just a small single garage and currently has roof beams running lengthways (70 x 35mm at 560-580mm centres) as shown in the pic:

I presume that the current set-up wont support boarding, insulation and a person (I still want to use it for storage so will need access), however if I were to install beams supported from the side walls (using something like this) so that they support the existing as well as the additional weight would that work? If so how many cross beams should I be looking at adding? (I know I should speak to an engineer, but I’m just trying to work out if it’s feasible at the moment).

I’m also intending to insulate the garage door etc. Thanks

Just wear a thicker coat.

That’s the way I’d do it (take the existing ceiling out first), but it sort of depends on what you want to store up there. Insulation weighs very little really.
Space the joists at the width of your choice of insulation to make installation easier – a builders merchant will tell you what size joists to go for.

will be worth it …..

i just kingspanned the roof of my garage – outside last week was -4.5

inside with no heating on it was +0.5 and my tools have been saved from the torrential condensation issue that plagued them pre insulation.

Screw a plate to each wall and jiffy hanger off that with your new joists. Shortest span across width obviously!

insulate ABOVE your suspended beams etc – then you’ll be warm but also keep storage space

best of both worlds then, just use kingspan which is cut to friction fit in the eaves – so along as you keep a 2″ gap between it and the exterior board so air can circulate

The existing “ceiling” timbers is the bottom section of a roof truss.. Please don’t remove it (unless you want the front and rear walls to be pushed out by the roof spreading)

You can work out the size of timber section required from here…

Work out how much your insulation and boarding is going to weigh (in kN) to determine correct section and joist centre for your span – as a guide.. the lowest rating there of .25kN is equivalent to 25kg per m²

Jeff

The existing “ceiling” timbers is the bottom section of a roof truss.. Please don’t remove it (unless you want the front and rear walls to be pushed out by the roof spreading)

Good advice 🙂

70×35 is pretty standard for truss timbers, you can quite easily store stuff up there without going crazy with weight. I quite happily will stand on one ceiling timer of a truss at 80 kg point load.