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By MikeG.
#1221738
75x38 such that the wall was 75 thick? Do-able, depending on the dimensions of your shed. You might need some noggins.

75x38 such that the wall was 38 thick. No.
By dom68
#1221773
thats good news mike.. yes meaning the walls would be 75mils thick. i was planning dimensions of 8ft x 6ft but this can be adjusted if need be.. will i need a rethink?
By ObservantGround28
#1222399
Incredibly helpful info in this thread.

I'm looking at a version of M's Shed clad in Plastisol coated box profile roof sheets on the back and sides rather than feather edge, etc. as I want to get it as close as possible to the boundaries and not worry about maintenance. Fences will be as tall as the walls so in theory it should be well protected at the back and both sides by any direct rain, snow, etc.

Anyone else looked at using plastic coated steel sheeting for this purpose and would you recommend it?

Thanks
User avatar
By MikeG.
#1222400
That'd do a lovely job. If you are using this vertically, then you'll need horizontal battens, and they should be on vertical counterbattens........all of which alters the thickness of the wall and the junction detail with the plinth. Just be very sure of your insect mesh detailing, because the profile will make that a little more complicated than with a board. It's quite a big deal, too, because wasps or bees in your wall could actually render your workshop unusable for a summer.
By Angel1058
#1226904
Hi

Looking at an 11m by 5m shop - and based on this, will have a concrete base. Do I have to have reinforcement steel in the base - those grid like rebar things?

Cheers
By ObservantGround28
#1248537
ObservantGround28 wrote:Thanks Mike. I'll look into this and post back what I'm going to do for anyone else thinking about this.
. I ended up building it out of blocks and put a fibreglass roof on it. Exhausting work - figured I’ve lifted over 10 tonnes excluding all the digging I did.
User avatar
By That would work
#1260731
Hi
My projected build will be going up to a boundary fence. Therefore I need to make the outside on that side sealed. I am intending to cover an outer skin with osb and seal this with bitumen and felt. It will be built in 8x4 sections each one being stood on a couple of courses of brick. So, as I will have a sealed exterior skin, should provide ventilation on the inside skin osb? I'll be insulating in the cavity.
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By MikeG.
#1260741
On the boundary? Then if you are above 15 square metres you'll need to comply with Building Regs, which means fire-resistant materials within a metre of the boundary.....which would rule out OSB.
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By That would work
#1260832
Hi
Unfortunately not, its 11.5 sq m. I was thinking of sealing the outsides of each panel and then also standing corrugated bitumen sheets between the boundary and the outside wall (of workshop) that sit under a draped flashing from the roof and in turn have their bottom edge sat in guttering (well below dpc) which then runs off of the upstanding base. This should ensure that not only the external timber is sealed but also kept completely dry with the corrugated sheets... and also allowing airflow between. So should I ventilate the voids in the wall with vents on the inside skin that is. It will be a 75mm cavity.
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By MikeG.
#1260838
If this was a store shed, it wouldn't matter. But if it is to be heated and you are going to work in it, then ideally the OSB would be on the inside, and a breathable membrane would be put on the outside, battened out, then a ventilated void created to whatever rainscreen you intend. You could fix the corrugated sheets direct to the (counterbattens & battens on the ) wall, rather than propping them in an ad hoc way, but you would need to add horizontal battens to your vertical battens. I strongly advise against felt and bitumen on OSB as your outer wall. Maintenance would be virtually impossible, and the necessity to get ventilation in behind it makes the detail difficult.
User avatar
By That would work
#1260840
Ok, interesting, Hadn't thought about using the sheet for the outside, automatically giving plenty of airflow. So a 3x2 stud frame with corrugated on the outside... and could let each sheet drop just over the brick base top edge on the outside. I should also be able to arrange a decent vertical overlap as I can screw from inside the stud frame to pull them together. What insulation would you recommend?
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By MikeG.
#1260842
Careful, though. It doesn't just give airflow, but access for insects and vermin. You'll need to design in some insect mesh.

Insulation? Mineral wool/ fibreglass is fine for a shed. If you want something more expensive but a better insulator, then Celotex.
User avatar
By DBT85
#1336823
Mike,

Was originally thinking pent roof but now looking at apex with a structural ridge. If only I knew anything about any of it! ha.

I'm sure you've answered these many times before but am I right with

a) a pent roof will need bigger rafters than a apex roof.
b) a non structural ridge (board) needs the walls tied together with rafter ties (do these have to be on top of the wall plate or can they be further up?)
c) a structural ridge (beam) needs its weight (and the weight it bears) transferred down into the end walls, but does not need rafter ties.

I'm fortunate that my back garden is around the 300sqm mark so even at the biggest I'd only be losing just over 10% to a workshop.

I'd probably look in the direction of 6.5x4.5m ish with the 6.5m ridge so i imagine that's a large lump of tree to take the load or just use a steel. That'll be fun to lift :shock: I imagine a ridge board and rafter ties 1/3 of the way up the rafters is the substantially simpler solution at the cost of a little ceiling height (that my 186cm frame won't be using anyway :lol: )

I note that in Dom's thread (in a reply a year ago!) you say
Depending on your ground conditions, you may well not need anything below your slab other than sand blinding (to protect the DPM). Hardcore or Type1 /2 are for consolidating soft or wet ground, or for building up levels. If you don't have those conditions, then don't use it. As soon as spring arrives, you should dig yourself a trial patch in the area of your workshop, and see what the soil conditions are like. Ideally you'll remove the topsoil and bed directly onto the top of the subsoil, and if that is firm enough, just put an inch of sand over everything.


Can you elaborate on "ground conditions"? For example when calcs and things were done for the GSHP install 100m down the road we were told that its clay all the way down to something daft like 300m. I don't have to dig more than 75mm in my garden to hit clay.

Also you obviously mention MOT type 1 as the aggregate. If I have a handy mountain of brick/concrete laying around on the farm and I also happen to know a man with a crusher, is that an option instead?