Garage roof insulation

[Nick Mace]

Are there any builders out there who might be able to give me a bit of advice?

I have a room above my garage which I've decided will make a decent woodworking workshop (it's a bit smaller than is ideal, but  whenever has a workshop been too big??).  It's a pitched roof with open rafters - i.e. you can see the roofing felt (which is under a slate roof).  I'd like to tart it up a bit and I'm thinking about cladding the interior with something like tongue and groove.

I think it would make some sense to add insulation whilst I'm at it.  It's not going to make a huge difference but it might stop it being completely roasting in the Summer (I'm worried about it being too hot as I can always put another jumper on in the Winter).

I've had a bit of a look online but get confused about air gaps, condensation, hot/cold roofs etc.

Can anyone give me some simple pointers about what materials to consider (celotex foam?) and how to install it (e.g. where to leave air gaps etc.)?

The only other factor which might be relevant is that I'm going to have recessed lights in the cladding.

Any thoughts welcome...

[Mark (smokey mow)]

Can you give a bit more detail and i might be able to offer a few suggestions.

 

What type of felt do you have?

What is the depth of the rafters?

Is headroom in the loft room currently an issue or likely to become an issue?

[Nick Mace]

Thanks Mark

I’ll take some measurements and have a look at the felt tomorrow.

Headroom is an issue so I’m limited to putting insulation between the rafters. 

Nick

[Nick Mace]

I’ve had a look and a measure.

The rafters are 140mm deep and spaced 350mm apart.

I’m not sure what you call the roof felt, but it looks like an older, bituminous style?

Here is a photo of the felt, and of the general roof space.

Thanks