Insulating Garage Walls

[Hightower]

Wondering if anyone has any experience of insulating garage walls?

I'm in the process of improving my garage which is also my layout room. I've already had the roof sorted, got a nice new door, and insulated the ceiling. The walls are single skin blocks, with the outside rendered. Not had any moisture coming in since the roof was sorted a few years ago.

My thoughts at the moment are to use 50mm PIR boards against the walls, treated battens attached to the wall between each PIR board, all overboarded with 12 or 18mm ply.

Does this sound like a sensible solution?

DIY forums seem to have a confusing mix of opinions, with talk of air gaps, vapour barriers etc. Should I fit a vapour barrier between the insulation and the ply, or does the ply act as a vapour barrier?

12 or 18mm ply? I've read that 18mm can be useful for attaching things to it later on, which will be good for attaching permanent baseboards to for my planned layout extension, but then I would have the battens to screw through to. The down side being 18mm ply boards would be very heavy to work with and is expensive.

Ultimately I'm looking to create a nice environment which I can still go and work in during the winter months. Doesn't need to go up to house temperatures (happy to wear a coat in there), and preferably not loose too much floor space. The more space I keep the bigger my layout extension can be!

Hopefully someone's got some background in this or done a similar project before.

Thanks.

[njee20]

I'm far from an expert on this, and like you I was totally overwhelmed by all the opinions. I used the insulation-backed plasterboard, bonded directly to the walls with Everbuild Pinkgrip (which is awful stuff!). I did it through sheer laziness versus stud walls and separate plasterboard, but it also had an integrated vapour barrier, and frankly worked out quite cheaply. We moved out after 6 years, but it was all still up! Made a huge difference to the temperature stability, well worth doing.

[port perran]

My layout room is in my garage which is attached to the side of the house.

We kept the front 3ft or so of the garage as a storage area but had a stud wall (insulated) with door access separating the storage area from the layout room.

The external side and end walls have been insulated (Celotex type stuff) and finished with plasterboard.
I had a floating floor installed with again Celotex underneath acting as an insulating barrier.

Finally I had a false ceiling put in with insulating material above it.

All pretty cosy and dry although I do have a glass panel smart heater in there which I can switch on in advance from indoors (to warm up a bit before I go into the train room) but that's only on really cold days.

[Webbo]

Probably many ways to do your insulating job, but here is the way I did mine.

My task was to insulate the walls of a room in my 'tin' shed. First, I built a wooden frame to sit against the walls out of 2 x 4 treated timber as shown in the first photo. The second photo shows how the 100 mm fibreglass battens were inserted within the frame and held in place by plywood sheets (8 mm I seem to recall). The ceiling was insulated in a similar fashion. The bench work was eventually screwed into the wooden studs.





The whole business works like a charm and provides a nice climate in the room both in summer and winter with the aid of a modest reverse cycle air conditioner.

Good luck whatever you decide on.

Webbo

[Bealman]

Having visited Webbo's layout in winter, I can confirm that. It gets cold in Canberra, and it was cold that day. Inside the shed, perfect!

[Bob G]

I would look up your local building regulations to get the most recent specifications for overall wall thicknesses otherwise you could fall foul of all sorts of things when you come to sell. A garden office made of wood is a different thing to a brick building and part of the issue is the use that is made of the building.
I thought our house was modern but in the 20 years it has been standing, double skinned wall thicknesses have increased by a good 30mm or so. As we found out when we extended...

Bob

[GlenEglise]

After I had moved into my house I had the garage prepared with stud strapping and plasterboard.

Now using one of the two garages for the layout I have laid fibre board on the floor covered by an old carpet and used a foil blanket insulation over the metal door. My other garage had been done previously and had stud and strapping with insulation across the metal door faced with plasterboard.

Seems to keep a reasonably decent temperature and humidity throughout the year. In Central Scotland near sea level I still use some trickle heat in the winter and have de-humidifiers placed but these rarely need replacing.

I hope this helps your decision.

GE

[Hightower]

Thanks for all of the input.

Think I am going to go with 50mm PIR between battens, taping between the edges, then 12mm ply on top.

Now to get ordering.