Thread: Shed Construction Cost

Originally Posted by melonhead

Hi all,

I've just bought a home and will be putting a reasonably large shed in the backyard. (NSW Illawarra area) It's a 18m x 6m shed with a skillion roof from Ranbuild which is quoted at just under $20k (not including slab). I've asked for a quote on construction and that came in at $7k.

While I had expected the shed to be about that price but hoped it would be less the construction cost seems very high to me. Any opinions?

From past experience a common calculation of erection costs in NSW is to use the 30-33% of shed kit cost. The height of a shed can influence final cost as well.

Originally Posted by Shedblog Au

From past experience a common calculation of erection costs in NSW is to use the 30-33% of shed kit cost. The height of a shed can influence final cost as well.

Thanks for the reply. I actually had two quotes one for skillion and one with gables and the gable was about $1k cheaper supply and constructed. Just for curiosity how much would someone in QLD charge?

Hi, I'm in the process of finalising plans to have a shed put in my new back yard as well (Southern Highlands). We got 3 quotes, and 2 of the places didn't seem particularly keen on the business - they didn't quote according to our specifications and then when we asked (again) for a revised price including our specifications we got short shrift. One of them was Ranbuild. We've decided to go with Fair Dinkum Sheds - the local franchisee at least. They took into account our requirements, have made changes a number of times at our request, and have made a site visit prior to providing a final plan and quotation. We certainly haven't rushed this process because I want to get it right, and of course I won't know if we've chosen the right company until the shed is built and I know whether I'm happy or not, but so far they've been good.

I'm getting a 12m x 9m shed (so same internal size as yours) with a gable roof and all up including slab it will be a bit over $32k I think.

I would suggest getting some comparative quotes from local suppliers and go with the one that you get the best gut feel from. We're not going with the cheapest (nor the most expensive), but the one that we felt most confident would give us a good quality shed for a reasonable price. Hope that helps.

Recently put up my new shed, 10000 x 9500 x 3600 walls. ALL timber framed, timber trusses, etc, on 100mm slab, colorbond. Including lights, power, lining walls with yellowtongue flooring, 2 x 3000 x 3000 electric remote roller dooors etc Oh and a 900mm wide x 1300plus long loft. Cost all up: around $30k. It is an awesome shed and it adds seriously to the property value (should see my council rates!)

I used "shed makers" here in WA and built one of their 6 x 7 meter kits (at 2.7 wall height), and the kit was $6.5K. They bring them in from China, sheets all pre cut, frames all hot dip galvanized engineered portal frames that you just bolt together. In that cost was a 5.o meter wide 2.2m high electric roller door, personal door, and 2 windows.

Yours at almost 3 times the length of mine sounds "about right" at approx 3 times the cost.

I met a guy at shed Makers when I was buying mine who bought one 6 x 5 meters, and I ended up erecting it for him - charged him $1700 or roughly 1/3 of his kit purchase cost (~$5500).

I'd say your slab will run you ~$5000 ish based on what mine cost me.

When I put mine up I spent extra to insulate the roof with air cell foil foam sandwich and a support mesh to keep the foil from sagging. This is worthwhile considering if you don't want condensation running down the underside of your sheets & dripping off the inside of the roof, at all the purlin lines specially if your storing anything like furniture etc inside the shed.

By the time I have storage shelves, lights power, etc etc...the sheds cost around ~$15K all up from the $6.5K I bought the kit at and I did all the erection of it without paying anyone to construct it.

Its amazing where all the costs go & add up... getting a truck load of sand in to compact under your slab, I did large individual concrete footings under each of my portal frames ($1K for ply form works, steel reo, and concrete to construct the footings). A bob cat to remove the grass out of the shed, and a fair bit fixing and re routing all the reticulation pipe that the bob cat dug up... and so it goes. Lights Power...Water, it seemingly never stops...











Had I paid someone to construct it, I hate to think that the total cost might have been a tad the other side of $17 or $18K by now...

The $ just seem to keep getting forked out one way or another BUT I am pretty happy with the shed..

Based on my experience I reckon you COULD end up spending a bit over $30K - $35K in total when it's all done...depending what standard you take it too - I could have just built mine on a slab and saved a bit on the footings BUT at least I know that with all the extra fly bracing (I strapped all my roof purlon's down to the frames as well) etc it will never blow away in a cyclone and I armor plated it with a zillon tek screws as well just to be sure.

I sat out a Cat 4 cyclone once...and you get a damn healthy appreciation for what nature can throw at you sometimes when she gets determined - horizontal rain and wind that howls like a banshee.... it MIGHT never happen BUT when it does?.... it's better to have taken that bit extra work to build it to a higher standard IMHO.

Cheers

Hi Poppa,

Thanks for the info. I've just emailed for a quote from FDS and will look forward to their reply. Although I like the new Ranbuild skillion sheds with the eaves as I think it would look less sheddie but I figure it's going to cost me (this is extra to the qoute I got too). Was the FDS agent you were in contact at Wollongong or Bargo?

Hi TT,

Thanks for the reply and the construction photos too. Also the various pricing information is very helpful. I might have to do a bit more research and get some more quotes etc. This might be a silly question but are then any issues that can arise from concreting of the footings and slab separately?

And yes I can see the extras or "other bits" adding up like the insulation + vermin proofing + storm water & water tank etc.

This might be a silly question but are then any issues that can arise from concreting of the footings and slab separately?

It all depends, its one of those how long is apiece of string questions...

For e.g. If you erect on footings first - and run your wall sheets down 200 past ground level - you then have your form work for pouring the concrete slab afterwards!

Also the concrete then forms to the profile of the sheet and doesn't leave each rib proud of the concrete edge, as a place for mice, roaches, and ants etc, to gain entry to your shed.

Wen you pour your slab around the footings in situ use a strip of expansion joint foam...to allow for any differences in rates of expansion contraction.

With my footings I deliberately formed them into miniature pyramids shapes, (600 x 600 at the base but only 550 x 550 at the top.

This way when the slab is poured around them any upwards movement is denied as the pyramid 'keys' into the slab poured around it...

Few people think or ave seen a concrete footing block, ripped from the ground and see no point to anchor it. I have (seen one ripped from the ground)! I built a large 10 x 10tmber shed ~ 30 years ago..with concrete footings and galv metal stirrups set into the concrete onto which 100 x 100 Jarrah posts attached.

After about 20 years... the shed got hit one night by a real life "tornado"... (Some people think we don't get them in Oz - but we did - the house with us in it, near the shed shook so much, that the wife and I both initially thought it was an earth quake...until everything went silent as they eye of the tornado went over us then the same as we copped the other wall of the wind...

In the morning, the roof was completely gone on the shed... and the roof trusses & timbers - there wasn't a piece of wood left longer than 6 inches... entire mature (300 years plus) Jarrah and Marri trees ripped off mid trunk like snapped matchsticks..

One of the 100 x 100 Jarrah Posts complete with stirrup and 600 x 600 x 600 concrete footing went with part of the roof - I found it near on a kilometer away on another farmers place.

Now days I anchor my concrete footings.



I actually do four legs but found it easier to just draw 2 in cross section on the PC. I am not an auto cad type guy sorry. MS Paint is the limit of my drawing skills on PC.

Anyway I drill my leg holes splayed out from the bottom of the footing form work box with an 8 inch hand long drop augur.

Then I put a length of about a meter of 8 inch PVC down the holes to stop sand collapsing in as the sand dries before the concrete is poured.

Then I drive a metal star picket down the center of the hole.... as reinforcing (You could use a few reo bars if you prefer).

I then put in the reo bar reinforcing for the footing and weld the ends of the start pickets to the reo to tie all the steelwork together.

Then I pour the concrete...

With 7 such footings (1 in the middle of the back wall & 3 down each side) there was about $800 in materials for form play sheets to make the form work reo and PVC & star pickets.

Many would say its overkill (waste of $ & effort etc)..... but my experience has taught me other wise. Maybe I'll never get hit by another tornado type event in my lifetime - but if I do - well I reckon the shed MIGHT stand up to it.

I can only show you what I do. Someone else may have a better idea / solution.

When I pour the slab around these footings - I thicken the edges down to 200 mm....and lay trench mesh... In essence I make it as imoveable as I can think how to do.

A pitched roof in a very high wind acts like an airplane wing, with one side of the pitch creating a wing in ground lift scenario - and lets face it fast enough air flow will lift a jumbo jet into the air.

That's why I go to the extra trouble & cost of anchoring down the footings to the degree I do - and why I fly brace all walls and roof (except those with opening doors & windows) & strap brace the roof purlins to their frames rather than just relying on little 14 g tek screws thru the purlin to hold the entire roof on.

Thats just how I do it, engineers and other builders, may find fault with my method, or a better stronger way to do it - that's what I could do with what tools & materials I had at my disposal.

Others mileage may vary.

In my humble opinion, erecting the shed and then pouring the concrete, using the wall sheeting as formwork, is a recipe for disaster. In my experience following this process will ensure that the bottom edge of the sheets will rust away in no time flat. And that is with genuine Colourbond, not the chinesean sheet.

I just cannot see a practical reason for doing it that way. Boxing is cheap, just pour the slab to the required measurements and then stand the portals and clad the thing hanging the sheet 30mm below the finished slab height. That is the way it should be done. That is the way I have been doing it for many many years.

It always sounds like a good idea to pour the concrete up to the sheet, like, "it will be vermin proof" yeah well it won't be once the bottom 70 or so or the sheet rusts away, and boy will that be a bugger to replace. Yep grind off all the concrete that has ended up in the ribs so you can replace the sheets.

Cheers

Hi TT,

Wow thanks for that comprehensive explanation and the details about the footings it's very informative. I certainly feel paranoid about cyclones and tornadoes now taking my shed.

Enfield guy is right about not using the sheet for forming.... due to corrosion. It even says so on my plans - but I did it anyway - I likely won't live long enough to see the sheets rusted away - as I said others mileage may vary.

I didn't mean to mak eyou paranoid - just passing on my life experience with a huge willy willy, cock eyed bob, tornado thingy, call it what you will. It was a real eye opener to see the fury of mother nature first hand. I felt real unlucky that I lost the roof (The roof sheets alone were $6K from memory) so i felt hard done bye at the time (and had no insurance either) until I realized how lucky we were that we didn't lose the house roof as well .

I've milled up some large Jarrah logs in my time and when you see trees like that twisted off mid trunk...as if a giant hand had just snapped them like a twig.

After losing the shed roof - I went up north and lived in the Pilbara for a year - thru one full cyclone season. We were on an Island about 3 miles offshore. BUT - we had a company house supplied back on the mainland (Pt Sampson) on the beachfront, to shelter in during cyclone evacuations, and stay in when we came to town fortnightly to food shop etc.

It was built for the govt as a harbor masters house for the cape Lambert iron ore loading jetty from Wickham mining ops. When the harbor master moved to Dampier the govt sold this zillion dollar house - that they had built specially to withstand a Cat 5 cyclone... out of concrete and steel. We evacuated to that house for one CAT 4 that the eye passed within about 20 kms...

The concrete and steel house with steel window roller shutters etc - water came thru below the window sills - from the horizontal rain, the house shook, and the wind screamed like a banshee for 12 hours.

It's not unless you experience these things first hand that you get an adequate appreciation for the forces of nature.

I'm not trying to make you paranoid -BUT if your about to build - and you do a little extra - maybe it will be the difference between disaster in years to come - or not. Or you might be like most people who seem to skate thru life with never a problem - me I seem to attract crap like fly paper so I've just come to expect the worst and now days prepare for the worst and hope for the best.

These days with global warming or sun spots or Nibiru / Planet X - whatever it is driving our weather nutso... it just seems to be prudent to maybe build to a cyclone rating on the off chance.

Heck I remember cyclone Alby that crossed the coast below Perth at Busselton one year.... normally they don;t make it down past Broome / Exmouth much... but not much seems normal any more weather wise.

Good luck with it... "Don't spoil the ship for a halfpenny worth of tar!".

Originally Posted by Enfield Guy

In my humble opinion, erecting the shed and then pouring the concrete, using the wall sheeting as formwork, is a recipe for disaster. In my experience following this process will ensure that the bottom edge of the sheets will rust away in no time flat. And that is with genuine Colourbond, not the chinesean sheet.

+1. Also see here from Bluescope themselves.

Surprising really how many people flout the recommendations of manufactures. Suits me fine, I'll come and fix it. Horrible job, hard to get the sheets off, specially when they lay a driveway up to it on the other side. If it is a 2 story place, say 6 metres high, it can add up to quite a deal of material supply for me. There are some tricky ways of fixing it such as fitting a toe mould and replacing lust the bottom say metre or so of sheet, but the you have the cost of the supply and fitment of the flashing as well.

As far as vermin proofing is concerned there are really two alternatives.

1. As previously described, hang the sheets 30mm over the edge of slab and fill with expanding foam. Works ok.

2. Make the slab 40mm wider all the way round, i.e. 80mm more in width and 80mm in length. Include a 40mm rebate that is 35mm or 40 deep where the sheet intersects. Put bitumin impregnated foam on the bottom of the rebate and let the sheets stand on that when installing. then fill the back edge of sheet with expanding foam. works great, costs more.

The reality is, as far as vermin proofing is concerned, there is only so much that can be done. Even the big buggers can get into surprisingly small openings.

Cheers

Yes - mines not even blue scope steel - mines case hardened plasticine from China made from recycled sardine cans.

The radiation emanating from it from Fukushima, just across the yellow sea in Japan, will likely kill me before the bottom rusts off.

I think I could manage a few short slip sheets to replace it if I live long enough...

Others are welcome to do differently - facts are all manufacturers warn against it and yet more than 50% are done this way according to the grano workers that poured my slab - who also ran the membrane on mine up inside the wall sheets to protect the wall sheets from direct contact with the slab and then trimmed the excess membrane afterwards so technically I don't have crete in direct physical contact with the sheets - but others mileage may vary!

I like my way of doing it, and am happy to take the risk.
Others might do well to do as the engineers suggest.

Your warranty on the sheets is voided if you pour concrete against the sheet direct, according to my plans notes BUT - the warranty on this Chinese crap is only 12 months anyway - and its been 12 months already since I poured mine and no rust yet, but the sheets are already out of warranty so the warranty's not worth the paper its written on anyway.

Maybe if you live by the beach and get lots of salt in your rain or something.... this rust issue might be real - thus far I've not seen any problem commencing yet - but that doesn't mean others will be the same.

We had a shed built back in 1999, and poured the concrete after the shed had been built all around the colourbond. If I knew what I know now, I would have poured the slab prior to cladding the frame. That stated, I have minor rust in a few places at the base of the walls. We also considered a high wind situation, and poured some of the foundation holes 1200 mm deep and then put a 125 mm slab on top of it. Double tek screwed roof and walls as well.

As an aside, back in the early 1970's I slept in a tent whilst a hurricane passed overhead mid-north coast NSW. When I awoke, caravans were on their sides 10 mtrs for where we were camped and we had no damage. (My Dad designed the tent )

I remember the stillness in the eye, everything was so quiet, then the leeward part hit us again!