Thread: A big shed. A long time coming.

Just finished my shed , one of the best feelings you can get , apart from electrics I did everything , I ran the wiring and lighting etc, my neighbor ( Sparky ) connected everything and tested it all , due to Council placement requirements ( steep block ) I was restrained to a 7.5 mtr x 4.4 mtr floor plan and a 15 degree roof angle .
That is big enough for me as there will be no vehicles , boats , storage or the like in the shed . Due to the angle of the block I had to cut in a bit and built it on duragal stumps at 300mm high , the frame and trusses are cca pine , insulated ceiling walls and underfloor , 3 double glazed windows and a colorbond corrie roof . The exterior is sheeted in Hardie 6mm and for appearance sake 2 sides have colorbond corrie , in the same color of the house , one solid timber door finishes it all off.
I am as happy a Pig in Poop , I retire this December and will have the shed to go to , Wifey says she will ring a bell when Dinner is ready .

You finally got aroundtoit!

I'll pull up a chair and watch this unfold

This could be a cool shed to follow.

Nice one Rod Watson.

Most impressive that you did all that yourself - particularly on a steep sloping block. That adds a whole new level of difficulty. Is it very cold where you are in Albany? The double glazed windows and underfloor insulation tells me you probably have temperature issues.

I like the idea the idea of the dinner bell. I might get one of those too, although I intend to run intercom and alarm/surveillance systems from the house to the shed anyway. My electrical system will be quite complicated, as I need to have 3 phase power mains and I will be installing a big solar system with battery bank and 3 phase inverter etc. Expensive, but worth it over time.

Have you moved your equipment and toys into the shed yet?

Regards - Wayne

Yes, the stars have finally aligned, Pat. I remember talking to you and Ray (wheelinround) about this several years ago, and discussing all the equipment I have gathered together that will find a home in the shed.

Long overdue. It was getting to the stage that some of the galvanised frame components have started to oxidise from sitting too long strapped together on the grass. It's not too bad - hasn't progressed to actual rust yet, and I'll attend to those areas in due course. This will be a big project - even for a builder. I intend to put a full bathroom and lunchroom in one corner, as well as a mezzanine floor right across one end of it - around 12m x 6m in size. Hence the 5.0m height of the shed.

Regards - Wayne

Originally Posted by Christos

This could be a cool shed to follow.

I hope it will be informative and entertaining to some, Christos. I'll try to include plenty of images as it progresses chronologically.

Originally Posted by Hardenfast

......

there is around 0.9 metre difference in ground level from end to end. This requires a excavation/cut at one end and the other end to be built up 700mm out of the ground - a "cut & fill" foundation....

If the slope was less of a difference and you had the fill could the lower end be filled? So as not to have a need to cut into the slope?

Originally Posted by Christos

If the slope was less of a difference and you had the fill could the lower end be filled? So as not to have a need to cut into the slope?

Yes, the slab could be built with no excavation at all and with compacted fill being used to build-up the low end of the site, Christos. I opted for a slight excavation (around 300mm) at the high end and used recycled concrete road-base to build up the low end. The result was that the top of the 150mm slab is around 750mm above ground level at the lowest corner and around 150mm below ground level at the high end.

I'll retrospectively contour the existing ground levels to suit driveway & drainage requirements where the shed has been excavated into the bank. I have my own 4.5 tonne excavator and tipper so I have an advantage in these matters that others won't necessarily enjoy.

Regards - Wayne

So, continuing the progress, I completed the small excavation (300mm deep) at the high end of the block and scraped the topsoil off the rest of the site, and pushed this excavated material aside as it wasn't really suitable for compaction underneath the slab. I then took the opportunity to gather up all of the broken bricks & tiles, lumps of concrete etc that were lying around and dumped all of this into the low end of the slab area as non-compressible fill material. I even broke up some old ceramic hand basins and toilet suites that weren't suitable for recycling and threw those in as well.

I have a concrete recycling yard not far from where we are located, and I can buy 6mm-19mm roadbase from them for around $25 per tonne. This stuff is perfect for slab-fill projects and is half the price of blue metal or crushed sandstone filling. I ended up using around 30 tonnes of this material and pushing it over the top of the other debris. Several hours of track-rolling over the top of this stuff created a very solid and nicely levelled substrate foundation. I should add that I have my own 4.5 tonne excavator and tipper truck, so am able to complete most of these works myself.

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Because the 150mm slab was to be so far out of the ground, the concrete formwork setup was quite significant. A 300mm wide edge-beam was required all the way around the perimeter of the slab, and the base of that edge-beam was required to be excavated at least 100mm below existing ground levels. This will prevent any filling material eroding or washing out from under the slab. The edge boards were therefore up to 900mm high and required a lot of reinforcing and bracing to prevent any blow-outs or movement during placement & vibration of the concrete.

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Next we will install our plastic membrane and reinforcements to get ready for concrete. Oh, and I needed to take a few more trees down.

H&F, that's a great size shed and thanks for the good pics and description. Is that a bag of chairs for the mesh that I can see?
When I did my first big shed floor in 1975, I got the local Lions Club boys in to pour the slab - but I didn't know about chairs for the mesh back then, and we spent all our time pulling the mesh up through the concrete, as it constantly sank to the bottom! You live and learn.
I trust you've had the cladding well covered and protected from moisture. I had a stack of zincalume sheets stored in my yard for a few years, uncovered, and despite being in a relatively dry area of the S.E. wheatbelt at that time, when I went to use the sheets, I found that they were well and truly corroded from moisture trapped between them, and they were utterly useless!

Thanks Wayne , no 3 phase available here , more is the pity , Albany can get cold but it can also get pretty hot . Have not long finished a new house then the landscaping then the shed so the toys are more like Makita than Laguna or Festool but I dont plan on any thing huge so I am sure I will get by , have just finished the dust control which makes a huge difference , still running the cyclone off a shop vac until I finish a proper centrifugal blower for suction . I picked up a proper 24'' forward curved blower wheel for nix , just have to build a casing for it .

Originally Posted by onetrack

H&F, that's a great size shed and thanks for the good pics and description. Is that a bag of chairs for the mesh that I can see?
When I did my first big shed floor in 1975, I got the local Lions Club boys in to pour the slab - but I didn't know about chairs for the mesh back then, and we spent all our time pulling the mesh up through the concrete, as it constantly sank to the bottom! You live and learn.
I trust you've had the cladding well covered and protected from moisture. I had a stack of zincalume sheets stored in my yard for a few years, uncovered, and despite being in a relatively dry area of the S.E. wheatbelt at that time, when I went to use the sheets, I found that they were well and truly corroded from moisture trapped between them, and they were utterly useless!

Yes, you need to have all of your reinforcement steel properly supported, Onetrack. Things get hectic once the concrete starts flowing and the last thing you want is to be constantly adjusting the height of your reo as the 'crete is pumping in. Bar chairs are cheap, and I always use more than necessary.
And you're right about the danger of oxidisation and corrosion when you have stacks of steel bundled together outside for long periods. Especially when it's on grass, as mine was. As I've previously mentioned some of the galvanised C purlins were already showing white oxidisation and some rust spots by the time I unstrapped it all, but this will be easily treatable. Luckily, all of the corrugated sheeting & capping was in perfect condition.

So now we get ready for the big pour. After plenty of compaction to the recycled concrete filling I installed some drainage lines for the bathroom fitments and laid down our polythene membrane.

We made up cages of 12mm deformed bar for the perimeter edge beams and also laid in 12mm bars across the edges of the slab with the ends turned down into the beam. We used F82 mesh right across the slab and used a 25mpa concrete mix. We made the slab thickness 150mm (6"), so with the perimeter edge beams it will be a very solid base.

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We pumped all of the edge beams first and vibrated them well, and then progressively filled in the rest of the slab, screeding to a laser-level as we went. Just on 40m3 of concrete in total by the time were done. Of course it began to rain as we put the whirlybird on it just to make things difficult.

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Next post we will start to put up our steel frames.

So now our slab has cured for a few weeks and we can start assembling our steel portal frames. These are big heavy mothers comprised of 250mm C Purlins with an overall span of 12 metres and a height at the ridge of over 6 metres.

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There's a few different ways to approach the erection of these frames, and your methodology will probably depend on the equipment and resources you have available. This is definitely not a job for unskilled workers, given the weight of the frames and the heights involved. We chose to pre-assemble the portal frames with the components laying on the slab, ensuring that everything was squared & braced to grid lines we had marked on the concrete, and then stand each one up in position as a unit. A lot of the 16mm bolt holes were pre-drilled from the factory but some had to be done on site.

The first portal frame is by far the most difficult to stand and brace securely. Once the first one is held perfectly plumb & rigid the second portal is a little easier, as you can fix your girts (120mm top-hat sections in this case) directly back to the first portal for immediate stability. With the first & second portal in position you can run all of your permanent bracing across the wall and roof spans, and then things start to feel quite secure. The third & fourth portals were fairly quick and easy to stand. Overall, everything went together pretty well.

We took the opportunity to install our roller doors while we had the scissor lift on the slab. These are both big commercial doors and are quite heavy. The main roller door in the end wall has an opening height of 4.6 metres. Now for some cladding sheets. There are also 2 pedestrian access doors to be installed which we will cut in once everything else is completed.

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