Thread: Simon's New Shed

This might have been in your favor as it might have got blown away last night if only partially erected.

They're back today to resume the job. Should be basically finished by the end of the week. Will post a photo this arvo

Which sets me onto the next steps - framing for insulation and plywood cladding. Does anyone have any references for how to build such framing? (wood dimensions, framing shape, number and location of horizontal bits, etc. What is the best way to affix to the floor/steel frame, what insulation to use, what ply to use?). The framing is 3 or 4m between spans.


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Simon

The considerations for framing would be around resistance to termites and spacing to suit the insulation. With bats you probably need one level of nogging to support the material in the vertical plane. Sheet materials may not need this. Stud spacing again would be dictated by the insulation material width. This framing is not structural as your shed is already structurally sound (we hope).

Regards
Paul

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I'm curious. Do these shed companies offer insulation and sheeting options or advice on how to do it yourself?

Pete

I took up their offer of roof insulation (seems to be some silver-coated sleeping-bag looking stuff).

Given that I want to line the walls with ply (OSB? other?) for shelves, french cleats etc, I didn't look into wall insulation options. I wonder if I can use those horizontal beams in some way? That looks heaps of depth for foam or bats. Would I need an insulation layer up against the corro?

Originally Posted by lyricnz

Given that I want to line the walls with ply (OSB? other?) for shelves, french cleats etc, I didn't look into wall insulation options. I wonder if I can use those horizontal beams in some way? That looks heaps of depth for foam or bats. Would I need an insulation layer up against the corro?

When we moved into our new place a few years ago, the folks that had it prior to ourselves had a colourbond shed, and had used the purlins to affix plywood to the walls which they then painted.

They had also opted for the Insulshed lining on only the roof. Insulshed is around 5mm thick, foam with "silver foil" on either side. It will be the stuff your chaps installed. There was none of this on the walls.

They only had the place for a few years, and when we moved in, given that I wanted to rejig the layout of the shed, I pulled a sheet of this plywood off.

The amount of black mould behind it was scary - we gutted the entire inside. The Insulshed product works like a sarking too, so what it does is it keeps moisture (actually condensation) out of the shed when both walls and roof are lined with it.

After gutting the inside, and getting rid of everything inside, we then had some shed builders come out, move doors and windows around, and line the walls with Insulshed.

The rest of our progress is documented here: Midnight's Shed

Suffice to say the framing is built from 90x45 for strength, with studs 600mm on centre. The backing is a builders wrap, and we're lining with 15mm plywood from TradeMaster Joinery. Framing is reasonably well documented, together with how it's held in place (carriage bolts through the framing structure of the shed, Raptr screws into the concrete floor).

It's a work in progress - we're no experts, just following theory and logic dosed with some pragmatic advice from product vendors and a small diet of Mike Holmes et al thrown in. Happy to answer any questions if you have any, but responsibility for answers not accepted as we're still rank amateurs

Having had a closer look at the shed overnight, screwing the plywood to the purloins certainly seems like the quickest option! Do you think that putting some Insulshed between the tin and the ply would be sufficient to prevent the mould? Given that this will now be a retrofit, would we use tape/foam to seal gaps?

Do you think there is any point in adding bats in the gap between the tin/Insulshed and the ply? (the depth there is wasted anyway). Making lots of framing sounds time-consuming, as your thread also indicates. I don't really need sound insulation (no neighbours), and the three roller doors probably negate much of the effect of any thermal insulation. But, you know, do it once, do it right...

How about strength? If I put some moisture barrier down, then rest the ply sheeds on the ground (or on a length of timber?), they should be strong enough screwed to the purloins? (will be french cleats mostly, with some cupboards. If I go for (really) high shelving, above the 2.4m ply, I might need a frame for that...

I used foilboard in my garage, between the tin and the plywood - but I wouldn't say it was air/water tight.

Originally Posted by lyricnz

Having had a closer look at the shed overnight, screwing the plywood to the purloins certainly seems like the quickest option! Do you think that putting some Insulshed between the tin and the ply would be sufficient to prevent the mould?

Yes. I'm building framing structure in mine for noise and thermal insulation, as well as having a solid structure to hang things off.

Originally Posted by lyricnz

Do you think there is any point in adding bats in the gap between the tin/Insulshed and the ply?

I would advise against this - if there is any condensation that will yet form, it will do so on the inside of the Insulshed (this will depend on what your climate is like - in 3 years, I have seen none at any time of year in the Hunter Valley). If there is condensation formed, you want a way for it to breathe - hence the gap between Insulshed and the builder's wrap in our design. I also note that we did not completely seal the bottom of our shed colourbond to the concrete slab (to allow minor air circulation), though we did install a vermin strip to prevent critters entry.

Originally Posted by lyricnz

How about strength? If I put some moisture barrier down, then rest the ply sheeds on the ground (or on a length of timber?), they should be strong enough screwed to the purloins?

This is how it was done originally in our shed, and yes, that will work - the sheets should have their weight supported on the ground IMO.

Thanks for your reply. Given that the shed walls are corrugated, and the purlins and blue vertical ones (what are they called?) cause a standoff, there will be air gaps all over the show anyway. Do you think even Insulshed would be required? Certainly no bats though.

FWIW, the roof is taller than a 2.4m sheet of ply, so they will probably be open at the top too, which should allow further evaporation

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Run all electricals in cable trays on top of any lining that is going to be installed. When changes are needed there is no hunting for wires etc. Avoid conduit except for drops from the trays to GPO's and machines.

Absolutely agree. Will be favouring flexibility and ease of update over hiding cables. Plus, at 2.4m up, will never see them

Originally Posted by lyricnz

Thanks for your reply. Given that the shed walls are corrugated, and the purlins and blue vertical ones (what are they called?) cause a standoff, there will be air gaps all over the show anyway. Do you think even Insulshed would be required?

I can only tell you what we found when we pulled the plywood off inside our shed - and in our case too there was a considerable gap between the metal outside wall of the shed and the back side of the plywood (61mm in our case). This, and the fact that there was air circulation was not enough to prevent condensation forming mould in our case.

Having pulled the lining out, we could confirm that in our climate, condensation was forming on the inner surface of the colourbond lining. Given that, we came up with our current design plan.

After having the Insulshed lining installed, we spent a good 12 months beginning our build, and this gave us a chance to "prove" over all seasons that our condensation problem was solved, and that proved to be the case.

Despite this, given the design of our lining (again, for thermal and acoustic reasons), we needed a backing on the frame walls - they were going to be too far away from the actual wall to support the insulation batts (in a normal install, the house cladding is only millimetres away from the stud wall, in our case it was over 60mm away). Given I needed a backing, I thought the logical choice was a builders wrap that would allow moisture to egress, but not ingress the wall.

Hope this helps clarify!

I think my gap would be at least that much, see photo below, but I take your point. Since this is retrofit, it's going to be a bit of a challenge to get the Insulshed there without cutting it to pieces. The blue things are screwed to the corro, and the purlins are screwed to them. Ideas? Besides lots of cutting slits in the insulation...

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Today's progress update

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