Is it possible/cost effective to insulate a prefab garage to use as a workshop?

WIAWSNB

https://forums.moneysavingexpert.com/discussion/comment/81957991#Comment_81957991

You'd need to ask the manufacturer of the panels whether removing some would compromise strength. I'd be very wary of doing this.

Adhesives are remarkably strong, but do need using correctly.

I'd suggest that the weight of the timber frame and insulation will not be an issue to the A-frames, given the serious weight the structure is already designed for and is carrying. And the ceiling isn't going to land on anyone even if it does detach - which it won't.

But, all the caveats apply - it is an untested suggestion, and you need to determine whether it's a goer, and your level of competence in carrying it out successfully.

Topher

https://forums.moneysavingexpert.com/discussion/6663592/is-it-possible-cost-effective-to-insulate-a-prefab-garage-to-use-as-a-workshop

I believe it is on the basis that my husband did that with ours, however it sounds like a different build. Concrete base, single layer breeze blocks except for four squared breeze block support pillars and a pitched (tilted) roof. He’d made the roof himself from some heavy duty boards (for external use) covered with heavy duty roofing “felt” and coating that with a specific to the materials weatherproof coating. Inside was some framework to which he added the insulation. The difficulty with the whole set up has been that there is a lot more condensation in this outbuilding than you’d get in something that was lived in and had air circulation and some form of heating. Our issue is how to set up the ceiling you get to see (under the insulation layer but over the workshop space), so that the condensate doesn't gather, form large drips and drip down or run along the ceiling (pitched angle). The answer for us seems to lie in both improving air circulation and having a degree of absorbency where the rising moist air hits the ceiling. without having heating in there it still keeps a good temperature for working in, even in more extreme winter weather.

KBM68

Im a barely competent bodger but I do have a couple of people who can sanity check my ideas and supervise (from a distance)

But they aren't up for coming up with the plan for the whole project and feel I have to put the thinking effort in.…so I asked you guys

On a budget is fine but stupidly cheap is dangerous and ill be careful

WIAWSNB

Let us know if the move takes place, and we can hopefully guide you if needed.

KBM68

The Survey gives me lots to think of:

"There is a prefabricated concrete and timber double garage/workshop to the rear of the property.
This has an asbestos cement sheet roof and glazed timber doors and windows.

The garage is in a poor state of repair and requires a repair and refurbishment programme. There
is visible rot, broken glazing and other minor wants of repair that need to be addressed.
The glass in the garage does not appear to be safety glass and this represents a health and safety risk. This glass should ideally be replaced with modern safety glass.
As noted above, the garage roof sheets appear to be of a material that may contain asbestos.
These appear to be in satisfactory condition at present and should present no health risk if
undisturbed. However, they should not be cut or worked in any way and specialist advice must be
sought prior to being removed as this will prove costly."

We need to weigh up the coat effectiveness of insulation/repair against replacement i think

teaselMay

I'm very much a fixer upper type person, most things I own have been repaired many times. But I think I'd consider starting again rather than investing energy and money in something that's already rotten in addition to limiting what you can do with it. It's worth pricing up how much it would cost to get rid of it completely and replace with something that actually meets your needs from the outset. Never fear there'd still be plenty of tinkering and getting it right as your workshop

WIAWSNB

The timber - I presume is doors and window frames - is rotting in places. Well, d'uh. Like every other garage of that age. Should every other owner of a similar garage rush out now and replace all the timber?

The glazing is likely to be non-safety type. Well, d'uh again. Like every other whatsit. Should every other owner of a ditto rush out now and ditto?

The roof is a-c, which is in good condition, but could present a hazard if damaged. Well, you know. Should every other owner of a ditt rush dit?

Q - what is the main structure like? It looks ok in the pics, and if it is, you still have the basis of a decent building.

Anyhoo, it's your call.

WIAWSNB

If the existing roof is in solid condition, then coating the inside with summat like SBR, and then installing a suspended ceiling which would isolate that roof space from the rest of the building will move what was an infinitesimal risk to health into one that cannot be measured at all. Unless a meteor hits you.

Section62

https://forums.moneysavingexpert.com/discussion/comment/81970076#Comment_81970076

The difference is "every other owner" isn't considering buying this garage (and the property it comes with) and converting it into a quasi-habitable room.

In other words, it doesn't make much sense to spend a substantial amount of money (and it will be substantial) turning the space into a year-round work room, but leave the rotting wood and (presumably single glazed) windows in situ.

The possible asbestos-containing roof is unlikely to be a significant issue if the sheets are in good condition, but again, if spending a lot of money fitting the space below out to habitable standard, does it make sense to leave the existing roof in place knowing it (probably) contains asbestos, may be approaching end-of-life, and provides very little thermal insulation (from heat, as well as cold).

Removing the asbestos now would be a relatively simple job - I'd still suggest getting a professional asbestos removal company to do it, assuming testing confirms the presence of asbestos. With the garage empty, the hook ("J") bolts holding the sheets in place can simply be cropped to release the sheets. No clambering around on the roof trying to undo the nuts, no angle grinders which can slip and dig into the asbestos. Once the roof is off the empty garage can be given a quick once-over with a Class H vacuum and the job is done.

Now try doing that after a suspended ceiling has been stixall'd below the asbestos, the walls have been internally lined, and the floor covered with finest Axminster. Getting access to the hook bolts now means removing the (expensive) suspended ceiling and insulation, and there are infinitely more nooks and crannies to try to clean out with the Class H. If you can't access the hookbolts from below then it means access via the fragile roof and hoping the nuts haven't rusted solid.

Changing the roof after the internal improvements have been done is a much bigger job (=expensive) than doing it first. So although the (asbestos) roof sheeting might outlast all of us, does it make sense to leave it there if it 1. makes insulating the roof harder and 2. means it will cost more to remove at a later date?

Like I said near the start of the thread, if I was going to the expense of making the interior insulated and lined, I'd start by replacing the roof. Ideally with something like plastic coated steel with a thick insulation layer underneath it. And use the opportunity of having the roof off to remove any panels to make additional window openings.

WIAWSNB

Fair do's, and if the property is bought, it would make complete sense to get quotes for all these options.