shed insulation using polystyrene sheets

[formula400]

right, currently got the father in law down with us, he come in to my shed to fix the compressor (he did) and said i should insulate and that I should buy large sheets of polystyrene, cut then and push them between the frame work, then cover with sterling board.

good idea???

will I need to do everywhere or if I leave a few not filled am I wasting my time,

roof as well???

[Jody]

I've literally just done this a couple weeks ago.

It took me all day as the numbty that built the roof didn't use a tape measure, literally no two beams were the same distance apart. every single piece had to be measured and cut by hand.
Cost about £250 in materials, worth it though.

[Count Steer]

I'd say it's a good idea. If you get the foil coated stuff, personally, I'd probably not bother boarding it, just wedge it in or glue it to the roof etc unless it's going to be a regularly used workshop sort of thing.

Still need a bit of ventilation and to keep the temperature above 7°C.

Oh, and check/seal the knots on the outside. I had some dry out and cracked over time and the inside wall got damp.

[formula400]

is this what I am after https://www.insulationuk.co.uk/products ... JoEALw_wcB

I don't want shiny walls

what's the best tool for cutting it???

[Count Steer]

70s disco vibe.

The coated stuff is easier to handle/less messy. Some options here and they have hints and tips on insulating sheds on the site too.

https://www.insulationsuperstore.co.uk/ ... board.html

I'd use a Stanley knife for the first cut and a hacksaw blade (you can get wooden handles for them) or a fine tooth handsaw as mentioned below. .

[ChrisW]

what's the best tool for cutting it???

You'll be fine with a decent hand saw unless you want an excuse to buy a hot wire cutter

[cheb]

https://www.secondsandco.co.uk sell cheap insulation. Guess why.

Demographic is your man for this.

[Jody]

is this what I am after https://www.insulationuk.co.uk/products ... JoEALw_wcB

I don't want shiny walls

what's the best tool for cutting it???

I used polyurethane, which was easily cut with a hand saw and can be trimmed with a decent retracting blade knife. But it does have a shiney finish to it, I guess you could paint it though?

I wedged it between the beams and then went over all the edges with foil tape, I also slung a couple battens up for overkill.

[formula400]

Ok, reflective is fine, I will cover them with some Sterling board.

https://www.insulationsuperstore.co.uk/ ... 200mm.html

https://plydirect.co.uk/product/osb-sma ... UHEALw_wcB

[Druid]

is this what I am after https://www.insulationuk.co.uk/products ... JoEALw_wcB

I don't want shiny walls

what's the best tool for cutting it???

I used Kingspan (foil covered stuff) to insulate my camper van. Cut it with a breadknife

[formula400]

So how much of the shed could I leave without the insulation???

For example I’d like to leave the back wall as I keep stuff there.

Also does the roof need doing??? I know it will make it better but am I wasting my time if I do 3/4 of it and no roof?

[Count Steer]

More is better but why not do the walls and see how much difference it makes? Personally, I'd do the roof even if it was thinner stuff than the walls (and not bother boarding it) but that's me.

PS it looks like you've had a bit of damp getting in on the left on the back wall?

[mangocrazy]

I'd use extruded polysyrene every time over expanded. Extruded is much tougher, cuts better with less mess and insulates a lot better. The foil backed stuff is better still but costs more. I'd do the roof first as the most important route of heat loss - heat rises and all that - then fill in all the major gaps in the walls. Ideally fill in as much of the gaps as you can then top off with ply or OSB which you can then fix stuff to.

And those single glazed windows will be a route of significant heat loss.

[Mr. Dazzle]

The foil backed stuff isn't polystyrene, if we're talking about the same stuff. Cellotex, Kingspan etc? I've used it loads for building environmental chambers, all Engineering R&D type places do! It's great, you just get it from Travis Perkins and black n' decker yourself a chamber around whatever test rig you're working on. Way nicer than polystyrene 'cause it doesn't "squeak", doesn't drop tiny balls everywhere and can do -70° to +150°C no problem at all.

I have no idea if it's a good/bad thing so far as sheds go, but the foil stuff is a much 'stronger' moisture barrier than expanded polystyrene. I've seen it completely iced over on the inside of a cold-box and totally dry on the outside. Demo is your man on whether you want that in a wood building!

[formula400]

More is better but why not do the walls and see how much difference it makes? Personally, I'd do the roof even if it was thinner stuff than the walls (and not bother boarding it) but that's me.

PS it looks like you've had a bit of damp getting in on the left on the back wall?

I know what you mean
It feels dry to the touch and I can’t see any holes.

[formula400]

I'd use extruded polysyrene every time over expanded. Extruded is much tougher, cuts better with less mess and insulates a lot better. The foil backed stuff is better still but costs more. I'd do the roof first as the most important route of heat loss - heat rises and all that - then fill in all the major gaps in the walls. Ideally fill in as much of the gaps as you can then top off with ply or OSB which you can then fix stuff to.

And those single glazed windows will be a route of significant heat loss.

Foil ones it is.

What kind of glue will I use to stick it to the wood?

[mangocrazy]

If you get the sizing of the insulation panels right they should be a tight fit between the joists/studs and not need adhesive. Measure carefully and cut fractionally oversize and the insulation will compress slightly as you push it home. Use a rubber mallet and block of wood to 'persuade' it to fit.

[formula400]

If you get the sizing of the insulation panels right they should be a tight fit between the joists/studs and not need adhesive. Measure carefully and cut fractionally oversize and the insulation will compress slightly as you push it home. Use a rubber mallet and block of wood to 'persuade' it to fit.

Cool, sounds like a plan.

Might go get some bits to start with tomorrow morning.

[Count Steer]

More is better but why not do the walls and see how much difference it makes? Personally, I'd do the roof even if it was thinner stuff than the walls (and not bother boarding it) but that's me.

PS it looks like you've had a bit of damp getting in on the left on the back wall?

I know what you mean
It feels dry to the touch and I can’t see any holes.

Knots can shrink in summer and swell in winter. We used to treat them with something called 'knotting' but I just treat them with all-weather silicone. Wipe it on and press in/smooth it with my thumb.

[demographic]

PU with foil coating, Cellotex/whatever.
Don't even try to get it exact sizing, its a pain in the arse and you end up braying it in covering yourself and everything else with dust. Tgen it still lets a fucking gale through any gaps.
Cut it too small so you can fit a foamgun nozzle all the alway round its edges, hold it in place temporarily with long nails or screws on a slant through the edges and into the studs.
Use a squirty foam gun to foam all the way around the edges, leave to cure then cut the excess with a saw (ideally a Multitool saw thing as its way neater).
That ensures its a perfect fit, well sealed around the edges, won't rattle or fall out in the wind.

Then, either put a vapour barrier on the inside (PU foam does allow moisture transmission and you dont want interstitial condensation) and maybe OSB boards on so you can paint the walls.

Polystyrene foam insulates well but squirty foam can eat away at it before the foam cures so I'm not keen on that.