Need Advice On Building A Workshop Shed

[charlie123Participant @charlie123]

Hello, I finally registered here after lurking for many years. I have finally enough money saved to build my dream workshop shed. I’m asking for advice on what to look for in a wooden shed;

(1) Does anyone have experience with the plastic honeycomb waffle plate type base? Interlocking plastic 50cm square plates, 5cm high that you then fill with gravel. Are these better than the old method of just putting the shed crossmembers on paving slabs?

(2) I want to get a large and heavy lathe like a 9 or 10inch South Bend (and a milling machine eventually) – do I need to reinforce the floor with double the number of crossbeams and/or double thickness floorboards?

(3) The shed will be 18ft or 20ft X 10ft, with the ridge running north-south. The windows will be on the east side. Should I see about getting a large overhang on the east side to shade the windows from the sun?

(4) Is 80cm a wide enough access walkway for infrequent use between the shed and a wall?

(5) Any other advice from people that have had workshop sheds built? What am I forgetting or don’t know about?

Thanks

[bernard towersParticipant @bernardtowers37738]

Think about a concrete perimeter for machines and benches. mine also has a comfortable wooden centre piece.

[JasonBModerator @jasonb]

i went with a concrete slab. Timbers on slab so supported along their whole length and a 300mm ctrs not theusual 400 or more. I layer of boards, insulation but battens above the joists and then 22mm flooring ply over that. I also have far eastern machines not heavy old iron.

The honeycomb is more just to stop gravel moving about due to light traffic rather than to give any better load bearing.

Insulation in walls and roof will have more effect on heat gain than an overhang unless you plan on excessively large windows

800mm is OK for access check if there are any regs regarding combustible materials withing a set distance from your boundry.

[Martin of WickParticipant @martinofwick]

At that size and with uneven loading, a concrete slab. Otherwise there will be differential movement. I have just had to bin a similar sized shed unit laid on paving that had conspicuously bowed in the centre due to settlement!

The unit I used was commercial but of high quality with 2x3s at 14 in centres and 18mm ply flooring. I added another 18mm 26 in ply runner around the perimeter to spread weight of the machines. Filled in the centre with some engineered oak flooring recovered from a skip! Bloody shed has better flooring than the house.

You can use translucent film or cheap and nasty IKEA blinds to reduce glare on sunny days and still benefit from good light on dull days.

Over 15 sqm you are likely to need planning permission and will be controlled with respect to combustible materials if you have neighbours.

Internally needs to have a breather membrane to the outer side and then 50 to 75mm PIR insulation on the inside and inner ply skin. Obviously insulate roof and floor too.

[Neil LickfoldParticipant @neillickfold44316]

I found that sealing the concrete, made a big improvement with the workshop environment. I suspect that in my case, the initial concrete floor was put down onto the ground without gravel or a polythene vapour barrier. My new workshop I also sealed the concrete floor with a commercial 2 pot sealer. Insulating the walls and ceiling also helps with keep the room temp above the dewpoint temperature, thus preventing the rusting of things. We also added a breaker board in the workshop with its own breakers for the power outlets and for the 3phase power as well. We placed the power points at about 1.2 m off the floor height. That way they would be above any normal bench height and more convenient for access. Also added a couple of power points in the ceiling near the middle so no walking over cords, with a chain supported drop lead. Has been very handy in deed. I am still to put in  the compressed air circuit. Also used an older kitchen extractor fan, to take away any fumes from things like soldering etc and is vented out the top of the side wall with a louver that shuts to keep the birds and bugs from coming in. In the corner I have an exhaust ceiling fan that vents through the eave and has a light that serves as a guide to it being or not. That takes away any smoke  fumes from turning quite effectively. Gives the room a change of air.

Happy workshop building.

[stephen goodbodyParticipant @stephengoodbody77352]

Hello Charlie,

The current edition of Model Engineer (#4749) and the following four editions (#4750-4753) cover this exact subject, in some depth, among my usual waffle. You may want to read those articles before taking the plunge, they cover a lot of things worth considering in your plans.

Regarding your specific questions, I largely agree with the preceding answers: a poured concrete slab laid atop a plastic moisture barrier, sealed moisture and vapour barriers on the outside and inside of the walls respectively, and no skimping on the sound/thermal insulation within the walls and roof.

Again, there are other really important and related considerations covered in the articles.

Best regards and good luck,

Steve

[David George 1Participant @davidgeorge1]

The last shed I have built was on a concrete slab Which was layed on a good hardcore base and damp proof membrane. The floor was good solid plank an a 3×3 frame and solid insulation between the concrete and plank floor. the walls were shiplap covering a solid frame with vapour barrier and inside a layer of fiberglass insulation was covered by tong and grooved plank. The roof was tong and groove outer with soild insulation butween an inside skin of tong and grooved plank all covered by two layers of bitumastic felt outer hot pitch sealed. A gutter and drain pipe system on the edge of the pitch roof collects rain water to water the garden. It has a small wooden double glazed window with inside locks and a solid double planked dor able to access a palette truck. The floor was also covered by a outdoor ply sheet 20mm thick for strength. Not forgeting to install wiring for lighting and sockets as well as mains consumer unit as and when a layer put on.

David

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