Thread: New shed - owner build vs shed company?

Originally Posted by Chris Parks

Unlined but on slab. Another problem the slab most probably introduces is the water loss from the concrete as it cures. It would cost a fortune to internally line it because of the size of the thing.

Anything that makes the air inside "wet" will cause a problem, including (as you say) the slab itself, until it has fully cured and dried out - and assuming it has a plastic sheet underneath to prevent soil moisture coming through! Sheds with fresh hay, or livestock, need much ventilation to prevent condensation, but older hay is no problem.

Any form of "break" between the roofing iron and the warm inside air will help to reduce the problem - Sisalation or AirCell under the iron makes a big difference! Other than that, the shed material makes little difference because the condensation occurs on the roofing iron, the purlins or rafters simply form a drip point. I had some timber from the roof of an old shed, and you could see lines on it where the condensation had run down from every corrugate......

Shed design seems to make a difference. I have a 3 sided skillion roof machinery shed and next to it is a normal gable roof shed (also 3 sides), both are all steel with dirt floors. The machinery shed has a long open side pointing east, the gable roof has a long open side pointing south. The skillion roof shed has no condensation that I've noticed, whilst the gable has lots. My assumption is that the gable roof catches the rising warm/wet air which then cools in contact with the iron and forms condensation, whilst the skillion roof just funnels the rising air up and out.....

Originally Posted by Warb

Local to me, C100 purlins are around $8/m, 100x50 sawn cypress is $7/m. Looking at my farm workshop, the horizontal purlins in the wall are at 1.3m spacings so assuming the same construction between timber and steel, an 8m length of wall comprising 4 runs (top, bottom and two between) would use 32m of material, costing $32 more in steel. However, from experience this cost pales in comparison with the cost of the cladding, insulation and lining, which would be the same for both. It is also worth bearing in mind that "normal" stud wall construction uses much narrower spacings of timber, so uses more material. If the walls are traditional timber framing with the lining directly attached, they will use vastly more material than wide spacings (timber or steel) with furring channels. However for a workshop, the narrower spacings and vertical studs give more opportunity to hang things later!

Edit: It seems to me that.....

The main reason that many up market project home companies use timber is simply that steel is seen as a "shed", and when constructing more complex (i.e. aesthetically pleasing) houses it is often easier to use timber. There are a great many companies, both project home suppliers and mainstream builders, who are now using steel framed construction.

The main reason that most (all?) shed companies use steel is because they can phone up Ranbuild (or equivalent) and have a kit delivered with pre-punched holes, no warping, twisting, shrinkage etc,. and assemble it with two spanners and a tekscrew gun. And no training in carpentry........

Having said all of that, if I were building a small shed and I had no recourse to outside help (with specialist knowledge and equipment) I would build it in timber, simply because I have the tools to do that and feel comfortable with a drop saw and nail gun! My actual choice would come down to my requirements, which is why my mancave is steel roof with cypress wall in-fills and weatherboards to match my house (because I can!).

It may be different out your way, Cypress isn’t readily available on the east coast of NSW and T2 pine is the standard framing material. 90x45 MGP10 pine runs out around $2.50/ m. And most frames are made with 90x35 and the budget builders use 79x35 for internal walls which is even cheaper again.
Steel is only used by less than 10% of the volume project builders and is at the lower budget single storey end.
The main reason shed builders use steel is because it is the most cost effective for that particular style of construction

I built my entire house out of cypress - better than having it eaten by termites! Some of it came from Sydney, the rest from Dubbo, but that was a few years ago.

I'm not a builder, my only comparison is that when we built the house, and made the fill-ins for my garage, we used what I believe is the standard construction of studs at 450mm centres with noggins between. That would seem to be a lot more material than steel at 1.3m (horizontal) spacings. Having said that, I'm assuming that the framing for a corrugated iron clad building wouldn't be the same studs and noggins construction, because the iron is attached in horizontal screw lines (due to the corrugations). Studs and noggins works for flat cladding, or weatherboards, where vertical screw/nail rows which follow the studs are used. The timber framed/iron clad sheds I have owned or seen are all much heavier timbers (4x2 or sometimes 6x2) on the horizontal, similar to steel framed sheds but with closer (horizontal) spacings and shorter spans. I suppose that the noggins could all be lined up horizontally to make the horizontal screw line?

Originally Posted by Warb

I built my entire house out of cypress - better than having it eaten by termites! Some of it came from Sydney, the rest from Dubbo, but that was a few years ago.

I'm not a builder, my only comparison is that when we built the house, and made the fill-ins for my garage, we used what I believe is the standard construction of studs at 450mm centres with noggins between. That would seem to be a lot more material than steel at 1.3m (horizontal) spacings. Having said that, I'm assuming that the framing for a corrugated iron clad building wouldn't be the same studs and noggins construction, because the iron is attached in horizontal screw lines (due to the corrugations). Studs and noggins works for flat cladding, or weatherboards, where vertical screw/nail rows which follow the studs are used. The timber framed/iron clad sheds I have owned or seen are all much heavier timbers (4x2 or sometimes 6x2) on the horizontal, similar to steel framed sheds but with closer (horizontal) spacings and shorter spans. I suppose that the noggins could all be lined up horizontally to make the horizontal screw line?

The spacing of the members for sheds be they steel or timber is generally based on the maximum spacing the external sheeting will allow and suitable/ viable member sizes, as they are not designed to be lined the support of internal linings is not considered. Steel For those sizes and spans is a more viable option than timber both for price and ease of construction

The point I was making before was that many members here fit their shed out as a workshop and want to insulate and line the walls with plywood etc which means they effectively build new walls to support their internal linings at 450 or 600 c/c which could of also supported the external cladding so are effectively paying twice for their structure

You can fix your sheeting to your noggin line if you wanted to but the standard more so now regardless if your fixing lines are horizontal or vertical is to wrap the exterior of the frame and fix batterns to the frame to attach your selected cladding to. This is done for improvement in the insulation properties/ thermal break and to allow your cladding to breath

Originally Posted by Beardy

The spacing of the members for sheds be they steel or timber is generally based on the maximum spacing the external sheeting will allow and suitable/ viable member sizes, as they are not designed to be lined the support of internal linings is not considered. Steel For those sizes and spans is a more viable option than timber both for price and ease of construction

The point I was making before was that many members here fit their shed out as a workshop and want to insulate and line the walls with plywood etc which means they effectively build new walls to support their internal linings at 450 or 600 c/c which could of also supported the external cladding so are effectively paying twice for their structure

I wouldn't call it "twice the structure".
On the miniorb lined half of the shed I just attached the internal sheeting to the girts just like the external sheeting.
Holding the insulation in place was done by using strips of builders plastic taped in place.Quite easy now that I think back on it.
Inuslation.JPG

For the gyprock half I did add some light weight steel 75 x 25 "C" section verticals between the top middle and lower girts at every 600 mm.
But it was nowhere near like building another wall.

Painted.jpg

Quite easy now that I think back on it.

Our planned house is large single story and it's steel frame. I'm not sure what counts as a volume builder, because they are not the largest but they are project builders with a finishes display room and display homes in more than one state. That said, they do make a big deal out of being steel frame in their marketing. I guess I had assumed that steel frame was not really a big deal in Australia. We went for them due to this particular large layout plan and the quality of their finishes. I hadn't thought they were up market but writing this I realise the reasons we like them come down to quality. So I'm not sure. The plan we have selected is their largest plan and we have extended it. So you see, I didn't really think of them as being in the top end of the market.

Anyway, I digress. That's just the house = hardly an important topic.

I talked to a shed company about the erection costs blowing out my budget. They pointed out that an American barn style requires less heavy steel and is easier to build. Hence cheaper for the same floor area.
So I'm going to get new quotes on a barn style building. Although I've given up on the idea of DIY for the shell. It's too big and I don't get along well with heights.

Originally Posted by Beardy

The spacing of the members for sheds be they steel or timber is generally based on the maximum spacing the external sheeting will allow and suitable/ viable member sizes, as they are not designed to be lined the support of internal linings is not considered. Steel For those sizes and spans is a more viable option than timber both for price and ease of construction

The point I was making before was that many members here fit their shed out as a workshop and want to insulate and line the walls with plywood etc which means they effectively build new walls to support their internal linings at 450 or 600 c/c which could of also supported the external cladding so are effectively paying twice for their structure

I wouldn't have thought that internal linings add much stress to the walls, compared to the force of a gale on the outside wall in any case!

I agree with your sentiment about doubling the structure, but I'm not sure that's what actually happens. Insulation requires minimal support, and I recall one of the sheds on my previous property used furring channels between the purlins, with no timber at all. That's also how we lined the gable roof in my toy shed, and if it works for ceilings I assume it would also work for walls!? Whilst I lined my toy shed with gyprock in the "neat" end and fibre/cement sheet in the messy end (easier to clean!), for a woodworking shed I think I'd prefer thicker plywood (for ease of fitting "light duty" hooks!), which is largely self supporting - certainly between purlins - but also very expensive. Significant additional structure, beyond that supplied by the purlins, would be needed only to hang shelves etc., and these days I use longspan shelving because I've needed to move things too many times in the past! My own woodworking shed is unlined, and the only built-in racking is for short term timber storage, mounted on vertical 90x45's attached to the purlins at 1.2m (from memory) centres.

One more thing that's just popped in to my head...... Corrugated iron, or trimdeck, when installed against a slab, leaves lovely little access points for mice and snakes through the corrugations. This isn't ideal! If the slab is poured after the walls are put up ("self forming slab"!) this problem doesn't happen, but the edges of the slab are messy under the purlins and there is a risk that the bottom of the iron will rust. If you have access to a panbrake and guillotine you can make steel sections out of matching flat sheet Colourbond (like a Z but with 90degree angles) that go under the iron and on top on the slab to seal those holes. I assume you can also buy them, and probably other solutions as well, because it seems too obvious not to have been commercialised!

Originally Posted by Warb

One more thing that's just popped in to my head...... Corrugated iron, or trimdeck, when installed against a slab, leaves lovely little access points for mice and snakes through the corrugations.

There's a solution for that - we had this installed on ours: Vermaseal STEEL, a BAL ember and Vermin proofing Solution | Steel Sheds in Australia

Originally Posted by Midnight Man

There's a solution for that - we had this installed on ours: Vermaseal STEEL, a BAL ember and Vermin proofing Solution | Steel Sheds in Australia

I knew it had to have been commercialized! We make our own by guillotining strips of colourbond/zincalume trim and folding them on a panbrake.

There is, or was, also a corrugated foam product for sealing the similar holes between roof purlins and corrugated iron, which works quite well to keep out the debris that otherwise blows in...

Originally Posted by DaveVman

Our planned house is large single story and it's steel frame. I'm not sure what counts as a volume builder, because they are not the largest but they are project builders with a finishes display room and display homes in more than one state. That said, they do make a big deal out of being steel frame in their marketing. I guess I had assumed that steel frame was not really a big deal in Australia. We went for them due to this particular large layout plan and the quality of their finishes. I hadn't thought they were up market but writing this I realise the reasons we like them come down to quality. So I'm not sure. The plan we have selected is their largest plan and we have extended it. So you see, I didn't really think of them as being in the top end of the market.

Anyway, I digress. That's just the house = hardly an important topic.

I talked to a shed company about the erection costs blowing out my budget. They pointed out that an American barn style requires less heavy steel and is easier to build. Hence cheaper for the same floor area.
So I'm going to get new quotes on a barn style building. Although I've given up on the idea of DIY for the shell. It's too big and I don't get along well with heights.

You're not building the McDonald Jones Bronte by any chance? We're heading down that path and once it's complete I'll be looking at an American Barn, around 9m x 14m.

Ill be checking out the stell pre-fab options, but also want to look at options of cladding the exterior to match the house. We're in a bit of a termite area so would prefer steel frame for the shed.

Originally Posted by I_wanna_Shed

You're not building the McDonald Jones Bronte by any chance? We're heading down that path and once it's complete I'll be looking at an American Barn, around 9m x 14m.

Ill be checking out the stell pre-fab options, but also want to look at options of cladding the exterior to match the house. We're in a bit of a termite area so would prefer steel frame for the shed.

Brighton Homes Bronte. We extended it.
I've just gone to McDonald Jones Bronte website and one of their variations looks very, very similar to what we are doing.
Digging a bit further and now I see they are both part of the MJH Group. Very interesting.

Which part of the country are you building in? We're in SE QLD.