Insulating a Garage - Possible? Worthwhile?

Nice building, I wish I had something like it , any how it would appear to be a single skin of blocks judging by the fact there's no reveal on the inside of the window, if you look through the forum you will find loads of posts regarding insulating a garage/out building.

 

Hi Stitchy.

As Phil says, yes - it is a single skin construction.

That's not a problem.

I'm guessing you won't need building control for this conversion of use? I'm also guessing that you want this done as cheaply as possible?

First - will adding insulation make a difference? Yes - a huge amount. Of course, insulating a building won't in itself make it 'warm' - you need a source of heat for that. Mind you, get a half-dozen peeps inside a well-insulated room and it'll get pretty hot on its own - and that's without anything naughty going on...

So, yes, it's well worth doing as it'll make the room much easier to heat and far more comfy to be in.

The simplest and most effective method of insulating this building is by using either Thermal Laminate Board - which is plasterboard with a layer of high-value insulation already bonded to it - or by first fixing on good insulation like foil-backed Celotex and then p'boarding over it. Same difference, but the combined stuff is easier - but it ain't cheap.

The TLB has the huge advantage of being able to be stuck straight on to the bare blockwork using 'dot and dab'. It should also have a few mechanical fixings - plugs and screws - to hold it too, say 3 or 4 per sheet.

A possibly easier way is to 'strap' the wall first with treated roofing battens - 2x1's - which are cheap. You can then fill in between the battens with 1" Jablite (cheap expanded foam insulation) before simply screwing the TLB on to the battens as you would on a normal stud wall.

Here's the thing; any insulation you add will make a huge difference. And, the more insulation you add the less the further improvement! Eg: 100mm insulation is nowhere near twice as good as a 50mm layer - it's probably only 10% better as a guess. And it costs a lot more and eats into your space.

I converted a single-skin attached garage into a 'play' room - 1" battens, 1" Jablite, and overboarded with the thinnest TLB I could find - 35mm overall thickness. That room is the cosiest and most easy to heat room in my house.

That's the walls taken care of...

The ceiling will need doing in a similar way - either TLB or else Celotex first followed by p'board. Again, TLB is easier - all done in one go. Since hot air gathers at the ceiling, more heat will be lost this way than through the walls, so it's worth adding extra insulation here. I'd be tempted to cut, say, 50mm or 75mm Jablite sheets and stuff them tightly between the ceiling joists making them end flush with the bottom edges of the joists before then overboarding with TLB. Again, the thinnest will be good, and thicker will be better - but not twice as good.

Happy new ceiling.

That leaves the floor. This looks like a recent build so the floor should have a DPM in it so no damp can come through. I think I'd still lay a DPM down there for the little cost - and take it a couple of feet up the wall before you strap/insulate the wall. Any idea if there's any insulation buried under there? Likely not.

Ok, what you do here depends on how much floor thickness you can lose. And also on what loading the floor has to take. You might get away with simply laying down a layer of, say, 50mm Jablite or even less, and then laying - floating - T&G chipboard sheets over it. End the sheets around 1cm from the walls, and fit the skirting boards down snugly on top to hold it down.

If this room is going to house heavy items of equipment and you think that a stronger floor would be sensible, then you may need to lay down 50mm thick joists at 600mm centres before in-filling with neatly cut Jablite, and then the chipboard flooring can be screwed on to these joists.

Again, my garage floor - because it was sloping - had joists ranging from only 25mm thick to about 120mm, and packed with Jablite and overboarded with softwood T&G floorboards. Cosy as a cosy thing.

Not that much heat is lost through the floor, so even a 1" layer of insulation will make a huge difference. Even the 18mm chipboard will do a lot of good...

 

But, if you need to do this to current BC standards, prepare for a significant extra cost and a significant loss of space inside - probably 100mm thick floors and walls minimum.

And it'll make precious little difference.

 

Once worked in a factory that had long lace looms in (all automatic) These were about 50 -60 ft long. The building they were in had to have the temperature maintained within a very narrow limit, otherwise the machines either seized up or produced work out of tolerance. First (and only) winter I worked there the heating packed up and within half an hour the machines had to be stopped.

 

Tee-hee .

This doesn't have to be expensive to get really good results. If you do this to BC standards, it will be expensive, but you can do this cheaply using Jablite or similar, and it shouldn't cost much at all.

Provided you don't have to pay for labour, of course...