Thread: Garage Workshop - New Build Advice

Does the slab have footings that would support a brick structure on top? Most metal sheds have very basic foundations due to the lack of weight.

Hadn't considered it, thanks for pointing it out...I'll try to locate the original build plans and find out.

Very unlikely that you'll be able to reuse an existing garage slab for a double brick structure. Not only do you require there to be perimeter footings, they must have much greater strength and stiffness for a brick superstructure than they do for a steel superstructure.

Post some photos so others can give ideas. A pretty basic tin shed can make a fantastic workshop with a lick of paint outside + insulation and wall linings inside.

I’ve got a tin shed on a decent slab with footings. Was part of the design of the shed. Portal frame.
I’ve split the 4bay ages into 3 areas, 1 bay for storage of camping gear etc, 2nd bay for office, kids work area and 2 bays for workshop.
Storage and office are lined with 90mm earth wool insulation and plasterboard, set and painted. Roof is with regular roof fibreglass insulation 50mm thick and then lined with 4mm hardwood brace board (easier to handle and install the brace board than player sheets all by myself).
Workshop is a work in progress but I’ve got 2 walls with 90mm earth wool and then 12mm plywood facing. All shed sealed with expanda foam and then a sprayed sealer to get the small holes sealed. The rooms with roof lining are very comfortable in the peak of a Qld summer. Workshop roof is unlined but with insulation and it’s almost impossible to work in there in high humidity and temps.
Power is split into each bay and power points at knee height then separate light circuit to each room.
Workshop is lights circuit and power points at chest height.
Would I do anything differently? Build it from timber frame and weatherboard to match the house better. We went with special horizontal metal cladding look metal sheets.
Would’ve insisted on the cladding going on after the frame was erected and then I would’ve covered the frame with moisture sheets. The shed was built by one guy so the cladding was installed with walls down then lifted up, so didn’t get the opportunity to put the moisture skin on. Not sure if that actually makes a difference.
Can’t think of anything else. Power and data cables came in thru the slab in one corner. Whirlybirds on the roof on each bay


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Thanks for the detailed reply, really appreciate your perspective!

As said, the existing slab wouldn't have been built with a brick structure in mind, so redoing the slab and then building would be expensive. Hadn't really considered keeping the structure as the corrugated tin didn't really register as a workshop material. But if I keep it and build an internal timber structure with insulation it would achieve the same result much cheaper - More $ for tools!

I'll look for some more examples and get a contractor and sparky in to see what this plan would cost. But sounds really good. Glad you guys talked some sense into me!

Again, post some photos so we can see the construction detailing of the shed. There may be better ways than building a timber frame.

My shed had three horizontal girts around the walls (top; mid height; bottom) and I fixed foil insulation sheeting to the inside of them, spanned Tophat 64 battens vertically across them on the inside, packed between them with Earthwool 2.0 HD batts and lined the inside with 12mm plywood.

This seriously strengthens the frame as well as providing a pleasing internal finish. My finished shed will have racking resistance (ability to resist horizontal wind loads) that is several times greater than the original strap bracing, plus all that weight guarantees that wind uplift is never going to be an issue. Not that my shed needed either but if your existing build is a bit flimsy, you can potentially resolve a lot of that by lining it internally.

Will do. Only just bought the place and will need to clean out the rubbish inside to get a proper look at things - I'm just trying to prepare as much as possible to do it first thing.

I think I can picture the setup you're saying. The horizontal girts look quite thin and it might just be one main one in the middle, but I imagine this would again work out cheaper/easier than a full timber structure. Once it's cleaned up, will post pics and make things either for suggestions. Thanks

Hi Flamingunz

I made the mistake of eye-balling the concrete floor of my then new shed and assuming that it was level and smooth. It is neither. It is an absolute pain. Workbenches wobble, stuff cannot be easily dragged around, dust lodges in crannies, etc. Now there is so much "treasure" in the shed that it is a major task to clear it before starting work on the floor.

Oonce you clear out the rubbish check the floor very carefully with straight edges and a good level.


Cheers

Graeme

Putting a concrete perimeter beam around the existing slab might be worth discussing with an engineer. The beam would have to go in anyway with a slab inside it so would amount to the same thing but then I am not an engineer.

One other thing. The original shed when we bought the property was an old style steel posts with hardwood stringers at 3 heights and steel roof frames. The posts went onto the concrete floor which had a much large base than shed. This meant that the side walls stopped at the concrete. This had 2 problems. It leaked every time it rained, flooded every summer from Brisbane storms and let little rodents in. Was very had to seal due to crappy concrete, thermal expansion and reason no.2. No 2 was the concrete leached and corroded the lower 50-75mm of the shed walls. I’m also told by a few sources that water running down the metal sheets generates an electrical charge of some sort and the water along the concrete is of different charge and this generates something that accelerated the corrosion. Don’t know if this is true. The sheets were old gal sheets from the 70s and the cut edges probably didn’t help long term.
Sorry I went on and on.
My new shed has the sheets extending past the concrete top, and drain straight to soil/grass. The sheets are off the concrete slab by a 15-20mm gap, hence the expanda foam and spray sealer. This gap was recommended by the shed supplier and installer


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Portal frame with top middle and bottom horizontal framing. Vertical furring channels for the horizontal weatherboard look cladding


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plywood lining and trim to cover joints, fixed to horizontal framers with roofing screws so screw heads don’t bury into ply. I’m sure there’s better fixings that would suit better?


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Gap between slab and cladding. With expanda foam


Wall onto the adjacent office


Power supply to powerpoints behind the horizontal framers, keeps the wiring out of the way


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Thanks for posting the pics, really puts it into perspective.

From here, I will clean it out and inspect the current slab and tin structure to see how solid and straight/flat it all looks. Will get a contractor to come and quote, just to see what their perspective is.
I'll post some more pics and see whether the above suggestions are viable and then make a decision on what to work on.

Won't tear it all down without more thought first!