Insulating new wooden shed

gunnerfitzy

Hi folks,

I'm getting a new wooden shed (18ft x 10ft) and I want to insulate it as it will be a utility / den / gym.

I've searched the forum and I've taken from many of the posts that the cheapest option seems to be fibreglass inside the inner frame and plywood over it.

Many recommend a vapour barrier however I'm unsure where this should be.

I've attached a pic of how the interior of the shed will be and would most appreciate any ideas on how best to approach this project.

Thanks in advance.

ART6

gunnerfitzy wrote: »

Hi folks,

I'm getting a new wooden shed (18ft x 10ft) and I want to insulate it as it will be a utility / den / gym.

I've searched the forum and I've taken from many of the posts that the cheapest option seems to be fibreglass inside the inner frame and plywood over it.

Many recommend a vapour barrier however I'm unsure where this should be.

I've attached a pic of how the interior of the shed will be and would most appreciate any ideas on how best to approach this project.

Thanks in advance.

First point -- thoroughly coat the inside with preservative and moisture sealant, because you won't be able to get at it again. Then tack to the uprights plastic film -- I used plastic membrane that is used under concrete, €25 for a roll (from a builder's provider) that would cover half my garden. I screwed 9 mm ply to the uprights and filled the gap with a mass of expanded polystyrene packaging that I had salvaged from all sorts of deliveries of things from shops, and had put through my garden shredder to reduce it to granules. Rockwool glass fibre would also do the job I guess, but I am a tight a**e! I coated the inside face of the ply with varnish to waterproof it (to be sure, to be sure).

The end result is bone dry, and I have walls that I can easily fix shelves or whatever to by simply driving in a few screws.

gunnerfitzy

ART6 wrote: »

First point -- thoroughly coat the inside with preservative and moisture sealant, because you won't be able to get at it again. Then tack to the uprights plastic film -- I used plastic membrane that is used under concrete, €25 for a roll (from a builder's provider) that would cover half my garden. I screwed 9 mm ply to the uprights and filled the gap with a mass of expanded polystyrene packaging that I had salvaged from all sorts of deliveries of things from shops, and had put through my garden shredder to reduce it to granules. Rockwool glass fibre would also do the job I guess, but I am a tight a**e! I coated the inside face of the ply with varnish to waterproof it (to be sure, to be sure).

The end result is bone dry, and I have walls that I can easily fix shelves or whatever to by simply driving in a few screws.

Thanks for the reply!

Is there any particular type or brand of preservative that you would suggest?

Would I be right saying that you suggest that after everything is complete the order of materials from outside in would be :
external timber - insulation (of choice!) - plastic membrane - plywood ?

looksee

I insulated a shed over 10 years ago by slotting rigid polystyrene into the spaces between the uprights, then covered it with plasterboard. No vapour barrier. It has been completely snug since then, to the extent that a computer that has been in there all that time still starts up no problem. It also has a double floor with insulation between, and rigid insulation in the roof with one eighth ply over.

.Henry Sellers.

I've a block shed and insulated the corrugated roof with kingspan, I regret not lining it first with a waterproof membrane while I was doing, It might of been overkill but you'd have piece of mind, One thing I did though is make sure there are no small gaps or cavities so that could mice can nest in it.
If you are painting the internal plywood to have a finish, keep away from soft sheen's and and mid-sheen's as the walls could be prone to condensation.

gunnerfitzy

Thanks guys.

I would be edging towards using some of membrane as I am in a pretty exposed area and the shed has little in the way of shelter to help protect it. If my research is correct the membranes are pretty cheap anyway.

If one was to go with a waterproof / breathable membrane, would the best location be between the exterior wall and the insulation OR between the insulation and interior 'wall'?

ART6

gunnerfitzy wrote: »

Thanks guys.

I would be edging towards using some of membrane as I am in a pretty exposed area and the shed has little in the way of shelter to help protect it. If my research is correct the membranes are pretty cheap anyway.

If one was to go with a waterproof / breathable membrane, would the best location be between the exterior wall and the insulation OR between the insulation and interior 'wall'?

I would always put the membrane immediately inside the outer wall, as it's much easier to fit it there by simply stapling it to the timber. I like Cuprinol as a preservative.

CMARTY10

gunnerfitzy wrote: »

Hi folks,

I'm getting a new wooden shed (18ft x 10ft) and I want to insulate it as it will be a utility / den / gym.

I've searched the forum and I've taken from many of the posts that the cheapest option seems to be fibreglass inside the inner frame and plywood over it.

Many recommend a vapour barrier however I'm unsure where this should be.

I've attached a pic of how the interior of the shed will be and would most appreciate any ideas on how best to approach this project.

Thanks in advance.

Make sure you put the shed up on blocks or a raised concrete base to stop the shed sucking up moisture also and kingspan for such small studs! Only reason anything is wet is because its been built wrong and leaking or soaking water.

gunnerfitzy

Thanks guys,

A few follow-up questions/points:

Would polythene be okay for the barrier or would something breathable like roofing felt be better?

I considered kingspan but thought that the amount needed for a 18 x 10 ft shed inc roof would be very expensive. Would I be right in saying that?

ART6

gunnerfitzy wrote: »

Thanks guys,

A few follow-up questions/points:

Would polythene be okay for the barrier or would something breathable like roofing felt be better?

I considered kingspan but thought that the amount needed for a 18 x 10 ft shed inc roof would be very expensive. Would I be right in saying that?

Personally I would never use roofing felt for anything. To me it is one of the world's most useless products. You are trying to produce a vapour barrier to prevent damp getting into the interior of your shed, so you need something that it totally impervious. Any plastic film will do that, but HDPE membrane is thicker and easier to use, and is dead cheap for massive rolls one of which would easily seal your shed with a lot left over. The timber of your shed will breathe quite happily to the outside, not to the inside where you don't want it doing!

Kingspan is great stuff, but it's costly and thick. You don't need that thickness. Rockwool is easier to use and it can be stuffed into place without needing to be cut into slabs.

I would always use 9 mm ply for the inner walls because it is generally cheaper than plasterboard, is not anywhere near as delicate to handle, and can be screwed to the wall and roof beams. When in place it can be painted with any emulsion paint of your choice, and it has the great advantage that you can then screw shelves etc to it wherever you like at any time. You can't do that with plasterboard. In addition, if it is screwed to the shed beams, you can take off a panel here and there easily if you later decide to run power cables to new locations. Again, that ain't easy with plasterboard.

A few years ago now I wanted a shed to store equipment in a dry environment. I bought a steel shed (same principles as for a wooden shed) that was made in Canada, would you believe, and it was a lot cheaper than I could have bought a similar sized wooden shed for here (God alone knows why!). I made a concrete base for it by first digging out an area six inches wider all round to a depth of about ten inches, and then hammered into that about six inches of dry mix concrete. I then used some of the membrane to lay over it to make a seal and poured a final (about) three inches of wet concrete.

When the concrete was cured I erected the shed and sprayed the inside of it with wax preservative (it was steel, not wood), and then I lined it with more of the membrane. I fixed wooden battens to the walls and roof, fitted the ply, and then gradually filled the spaces behind with insulating material. In fact, being a cheapskate, I had saved up all sorts of expanded polystyrene packaging that I had accumulated over a time, and I reduced that to crumb in my garden shredder and simply poured it into the gap. A shortage was made up with a couple of old duvets and some pillows that were ripped apart to recover their filling!

Once completed, I then poured self-leveling compound inside to create a dead level floor, sealed it with PVA dissolved 1:1 in water (a one litre can costs peanuts from any DIY store and is more than enough). Then I painted the floor with floor paint.

I have a shed that has stayed bone dry for a few years now, so dry that you could store Egyptian mummies in it without risk. In fact I might try that as my next project if I can find anyone who wants to be mummified!

whizbang

Vapour barrier goes on the warm side. ie. the inside of the shed between timber/plaster and the insulation.

Water vapour will pass thro, and around, most insulation, and condense into water on the cold side of whatever it meets.
It the barrier is on the outside of wool/fiber insulation, (cold side) the insulation will soak up this water and consequently rot everything it touches.
Polystyrene doesnt allow much vapour thro, but not good enough on its own. kingspan often comes with a foil backing which is a vapour barrier in itself. but you still need to seal the edges.

membrane is breathable, to allow vapour out, but not in. used on the cold side.

I think an ideal world is a breathable membrane on the outside of the insulation, and the plastic (HDPE) inside. with some heavy sealing tape on the joints, and wherever screws are going to penetrate.

gunnerfitzy

Guys, thank you all for your advice.

Hope to order the new shed next week!

ART6

Every man need a shed if only as a refuge from the women!

Maudi

ART6 wrote: »

Personally I would never use roofing felt for anything. To me it is one of the world's most useless products. You are trying to produce a vapour barrier to prevent damp getting into the interior of your shed, so you need something that it totally impervious. Any plastic film will do that, but HDPE membrane is thicker and easier to use, and is dead cheap for massive rolls one of which would easily seal your shed with a lot left over. The timber of your shed will breathe quite happily to the outside, not to the inside where you don't want it doing!

Kingspan is great stuff, but it's costly and thick. You don't need that thickness. Rockwool is easier to use and it can be stuffed into place without needing to be cut into slabs.

I would always use 9 mm ply for the inner walls because it is generally cheaper than plasterboard, is not anywhere near as delicate to handle, and can be screwed to the wall and roof beams. When in place it can be painted with any emulsion paint of your choice, and it has the great advantage that you can then screw shelves etc to it wherever you like at any time. You can't do that with plasterboard. In addition, if it is screwed to the shed beams, you can take off a panel here and there easily if you later decide to run power cables to new locations. Again, that ain't easy with plasterboard.

A few years ago now I wanted a shed to store equipment in a dry environment. I bought a steel shed (same principles as for a wooden shed) that was made in Canada, would you believe, and it was a lot cheaper than I could have bought a similar sized wooden shed for here (God alone knows why!). I made a concrete base for it by first digging out an area six inches wider all round to a depth of about ten inches, and then hammered into that about six inches of dry mix concrete. I then used some of the membrane to lay over it to make a seal and poured a final (about) three inches of wet concrete.

When the concrete was cured I erected the shed and sprayed the inside of it with wax preservative (it was steel, not wood), and then I lined it with more of the membrane. I fixed wooden battens to the walls and roof, fitted the ply, and then gradually filled the spaces behind with insulating material. In fact, being a cheapskate, I had saved up all sorts of expanded polystyrene packaging that I had accumulated over a time, and I reduced that to crumb in my garden shredder and simply poured it into the gap. A shortage was made up with a couple of old duvets and some pillows that were ripped apart to recover their filling!

Once completed, I then poured self-leveling compound inside to create a dead level floor, sealed it with PVA dissolved 1:1 in water (a one litre can costs peanuts from any DIY store and is more than enough). Then I painted the floor with floor paint.

I have a shed that has stayed bone dry for a few years now, so dry that you could store Egyptian mummies in it without risk. In fact I might try that as my next projeif I can find anyone who wants to be mummified![/Quo brilliant!

dharn

one think occurs to me those battens are only 3inches ? so your depth of insulation will be that, which will make very little difference to heat loss, is there a window ? it will steam up from heat generated inside, if you have not some ventilation so it could still be a very cold shed

gunnerfitzy

dharn wrote: »

one think occurs to me those battens are only 3inches ? so your depth of insulation will be that, which will make very little difference to heat loss, is there a window ? it will steam up from heat generated inside, if you have not some ventilation so it could still be a very cold shed

Hi. Ya those battens don't look too thick. I was going to put rockwool or similar in there. I guess my intention is just to have some degree of insulation while realising I won't be able to insulate it to the degree that I would ideally wish to.

Alun

I thought about the depth of those battens too, they don't look too deep, I thought maybe only 2" or so.

Now, I don't know where you're getting your shed from but when I was looking around for ready made sheds a while ago, one company, Abwood, was prepared to make one using deeper battens for me (4 inch IIRC) as a special order. In the end I had one custom made by a friend of a friend, but it's maybe worth asking your supplier if they'd be prepared to do something like that.

dharn

i think unless he really wants to get serious about insulating it he is wasting his time half doing it, a well insulated house with walls 12 to 14 inches thick with full insulation will be freezing cold without heat, so he would be as well off to just heat it while he is using it, and not worry about it when not using it

david75

OP, styrofoam packaging peanuts are excellent as insulation, moisture absorbent and cheap as chips.

gunnerfitzy

david75 wrote: »

OP, styrofoam packaging peanuts are excellent as insulation, moisture absorbent and cheap as chips.

Any idea what kind of places would sell these?

david75

Feck I meant water repellant, better and they'll last for long after we're gone. If you look up packaging supply places also I'm told you can get it at landfill or if you ask around industrial estates they'll happily let you take it off theyre hands as it's always just thrown out.

GreeBo

david75 wrote: »

Feck I meant water repellant, better and they'll last for long after we're gone. If you look up packaging supply places also I'm told you can get it at landfill or if you ask around industrial estates they'll happily let you take it off theyre hands as it's always just thrown out.

With such a thin depth Id stay away from these peanuts. You are going to get loads of gaps, also air is going to be able to travel between around them.

If you cant get it made with thicker studs I'd screw my own over it, or purchase polystyrene of the correct depth (Ive seen 1inch in sheets in B&Q)
Cut to fit and then seal over.
9mm wbp is fine to cover all this.

Stuffing in rockwool will render it useless, its designed to be left fluffy to allow it to trap air, if you compress it you ruin it.

You need ventilation otherwise your own breath will start to condense on any cold areas (roof, windows, door etc)


If you do it well enough your own body heat, especially if using as a gym, should be fine)

gunnerfitzy

Cheers guys

paddy147

gunnerfitzy wrote: »

Any idea what kind of places would sell these?

Any builders providers will have it in stock.

25,mm thick and 4 feet x 2 feet in size.
Around 1 euro-1 euro 50 cents a sheet.

It can be also had in thicker and bigger sheets too.



I use it for aquariams and fish tanks.:)

sharkbite1983

gunnerfitzy wrote: »

Guys, thank you all for your advice.

Hope to order the new shed next week! [/quoso I'm considering insulating my shed, and I found this thread.

If you don't mind me asking, did you insulate the shed? And how did it turn out? Most importantly, did it survive or rot? 🀣

gunnerfitzy

sharkbite1983 wrote: »

gunnerfitzy wrote: »

Guys, thank you all for your advice.

Hope to order the new shed next week! [/quoso I'm considering insulating my shed, and I found this thread.

If you don't mind me asking, did you insulate the shed? And how did it turn out? Most importantly, did it survive or rot? ��

You're asking me to go back a few years....

I did. I cut the polystyrene sheets to fit between the batons and then fitted the plywood. PITA job to be perfectly honest but it worked great. Moved houses a few years ago but it was fine up to that time.