New home workshop build options

jack of all

I know this has been covered before but I'd like to get some feed back on my own proposals for a small workshop build. I'm hoping to build something around 20'x 10', in a small garden, with tight access and a short timeframe. I had toyed with the idea of a timber frame structure which I could build myself with some help on the concrete base. However I'm going away from that idea now as I want something up pretty quick and I don't want to be left with a load of building materials sitting at the side of my house if we got a few bad weeks of weather. The fun part for me would be kitting out the shed and making the benches, storage etc.

I'm considering get an insulated steel panel shed, 40mm kingspan, with two steel doors, 2 windows and 2 rooflights, on an insulated concrete base. One end of the shed to have it's own door with internal timber stud partition, sheeted each side in ply and insulated. This sub-division (10x 6') will be allocated for the bikes, lawnmower and other crap that currently fills a 8x 6 garden shed to overflowing. The remaining 14 x 10' space will be my workshop/ hobby room. I plan to stud out the internal space, fill with rockwool, fix vapour barrier over and sheet out with 1/2" shuttering grade ply, maybe 3/4". Most stuff could be hung of this or the studs behind. Floor (concrete on insulation, on DPM on blinded compacted hardcore) to be painted with rubber matting or old carpet at bench/ workstations. I had thought about putting a ply floor down over battens for comfort but I dabble in a bit of metalwork and I don't think the timber would wear well with oil, metal swarf etc. I'm not sure about whether to paint or varnish/ seal the ply cladding. I would get a dedicated fuse board fitted with all wiring surface mounted in pvc trunking. I'd probably get some steel security grilles made up to be fitted internally over the windows and look at beefing up the standard steel door for security. What do you think, any other suggestions or alternatives? I know a block built option would be preferable but I don't want the mess, the garden is small and we would want something that could go up fairly quick, when the basic structure is in place I'd have plent of time to sheet out and make the space my own, at my leisure.

woodturner

Go with that. You'll need planning permission for a block built shed. I'm hoping to go down the steel route too for a 30' x 20' workshop.

jeepers101

woodturner wrote: »

Go with that. You'll need planning permission for a block built shed. I'm hoping to go down the steel route too for a 30' x 20' workshop.

Nonsense. Doesn't matter what its made of, its the size that dictates planning necessity.

Jack of all wouldn't need planning for a block shed. However, you would for your steel one.

Dozer Dave

jeepers101 wrote: »

However, you would for your steel one.

More nonsense, you dont need planning for a steel one.

jeepers101

Dozer Dave wrote: »

More nonsense, you dont need planning for a steel one.

That's ridiculous. So I can go ahead and build a 100sq metre 3-storey steel shed in my back garden?

Dozer Dave

jeepers101 wrote: »

That's ridiculous. So I can go ahead and build a 100sq metre 3-storey steel shed in my back garden?

Yes you can, declare it as an agricultural building

jack of all

Ok guys, I'm not worried about planning permission for now, if needs be I'll look for retention (I've made preliminary inquiries and I'm happy that I do not require pp), but right now I want opinions on construction type. This is a single storey "shed" for use by me and "ancillary to my enjoyment of my dwelling" etc etc blah de blah ; ).

Calahonda52

I would go block, 9" solid on flat and then consider insulating it from the outside, finished with a concrete board, on timber studs, u could do it at your leisure.

Leave the surrounding paths till after you have done this
The idea u have re sheeting internally is fraught with a number of potential interstitial condensation issues because the insulated steel is impermeable and therefore the vapour barrier u suggest is a waste of time and money that will only trap moisture behind it.

gutteruu

Your garden will be destroyed and the place will be covered in **** anyway as you still need the concrete base. If you have to put in footings you will need blocks and sand anyway so is it really that much more work to block and plaster it? But its all opinion at the end of the day.

If your going with steel shed with insulation, stud and more rockwool, would it not be much cheaper to go with bog standard steel shed, stud out inside and spray foam insulate the whole thing trimming it flush with your studwork?

(To clear up planning, its exempt if under 25m2 and leaves at least 25m2 of free space left in garden. Under 3m high for flat roof and 4m for pitched.)

jack of all

Thanks for the feedback- I had considered the interstitial condensation issue but I thought if I put a good vapour check on the warm side of the quilt insulation that I would mitigate this risk. I would consider sealing all gaps in the vapour check with an air tightness tape. However I am open to suggestions.

A block build would be far messier and more time consuming and I don't want to be taking on too much, especially in the way of wet trades that I can't undertake myself. I want the basic structure up fairly quick as we want to return our garden to normal as soon as possible and have it ready for the brilliant summer weather we're going to have! Once the basic shed is there I can work at my own pace to kit out the inside, once I have a roof over my head. Access is restricted also, with a narrow side passage, about 1m in width at it's narrowest point. In relation to the idea of single skin structure with insulation by me- I hadn't considered it but I will be costing both options. If I did go for the insulated panel perhaps I might leave out the quilt insulation and just have a ply lining. The ply lining is a no-brainer for me as the place I currently use has this finish and it's very flexible for hanging stuff and is has some sound absorbency and is good to look at too.

Double Barrel

I'm considering get an insulated steel panel shed, 40mm kingspan, with two steel doors, 2 windows and 2 rooflights, on an insulated concrete base. One end of the shed to have it's own door with internal timber stud partition, sheeted each side in ply and insulated.

Jack,
I would suggest making one of the door openings a double door.

Good luck and keep us posted.

jack of all

Double Barrel wrote: »

Jack,
I would suggest making one of the door openings a double door.

Good luck and keep us posted.

Thanks, I'll certainly consider it. Doing a measured survey of the garden today before I sit down for the afternoon and plan out the building and see how I'd fit out the internals.

recipio

As life goes on you will want machines and benchtop tools like grinders etc and possibly a lathe. I'd put loads of sockets, including one 16 amp circuit for heavy planers and sanders. A square shape is optimal for this. I have a long rectangle and am reduced to 'rat run' between the machines.!

jack of all

Quick update- I've had a busy 2-3 weeks of preparatory work to do myself: clearing a ditch, partially taking down an ash tree, taking up an old patio, chasing concrete footpath, putting in a new oil line, shifting a few tonnes of muck etc. Works for base proper started today, 20x 12 shed to be delivered by the end of next week, hopefully.

Thinking about the finer details now. I think I'll use 1/2" shuttering ply throughout for the internal lining- 3/4" is overkill and if needed I'll beef up 1/2" panels with scraps and off-cuts from the 8x 4 sheets- glueing these to the rear where a shelf support or hanging item may be screwed (extra grounds for screws and should stiffen up the sheets). I like the look of the raw plywood but like the idea of sealing them somehow. I had a bit of Thompsons Water Seal lying around so tried that on a scrap of shuttering ply. Seems to be useless (the new "improved" water-based Thompsons that is), I seem to remember the old solvent-based product actually did "waterproof". I don't want to go down the poly varnish route (expensive for the area involved and far to many VOCs for my lungs, any other suggestions that are cost-effective? As regards fixing the ply lining- I want to avoid mechanical fixings into the steel cladding or cladding rails, I want to use a construction adhesive to spot bond the studwork/ ground timbers to the steel. However the steel is galvanised- anyone know how these newer water-based construction adhesives react with galvanise? Does it bond well, does it attack the zinc coating over time? Not much info on any of the manufacturers about suitability. I plan to fix the ply lining through to this framework with coarse thread drywall screws (cheap and good holding power in softwood). I'll use a light deal skirting at the base, scribed to ensure a tight joint (don't want any potential entry points for mice), pre-primed and pre-undercoated for ease of finishing. That's it for now, any help with my queries is much appreciated.

gutteruu

Can you not just use self tappers to fix studs into the horizontal top hats? (Nothing piercing outer sheet). Load is downward through your stud wall into ground. Fixing to top hats is just for lateral support.

jack of all

@gutteruu
I could do that with tek screws but I want to avoid drilling the steel at all, if needs be I can use the odd fixing here and there but I'd rather use construction adhesive. I might just use screws at top clading rail, as you suggest, for lateral support. Bottom softwood sill plate will have to be glued to avoid piercing dpm as floor overlaps concrete ring beam at this point (to give a rebated/ stepped-down construction) and the floor is only 50mm thick at this point, on DPM, foil bubble wrap insulation on 150mm ringbeam. Wood bond to concrete will be good anyway. Thanks for your input.