Shed/workshop compromises, please help!!

[yeungster79]

Hi Guys, brand new to this awesome website I have waded through a lot of great posts on this forum and would like to attempt build a shed/workshop within a strict budget of about a grand (don't laugh!!) and with limited amount of time, I am hoping that you guys can help me with my decisions so that it doesn't go terribly wrong It would be great to attempt a Mike style workshop but I think that's not going to happen!!

What I plan on building is a 14' x 8' pent shed for holding my workbench and general storage, out the back of the garden. It's mainly to replace our pre-cast 1970's bomb proof concrete shed that stands close to the back of the house. We are extending the house and this shed must go. Time and budget is limited - so I need to make compromises. I wont be spending many hours in there every day so I can comprise on some aspects.

The floor:
I won't have the time to dig out the garden and pour a concrete slab. My initial thought is to go with 4'' posts dug down say 1.5 feet and set in postcrete with rubble under the posts for drainage. The posts rising 12'' above ground level, I think I would need to dig at least 12 holes to support the 14'x8' frame, screwed in with heavy duty bolts to the 4'' risers. The floor frame would be suspended above ground level by at least 6'' with a polyethylene vapour barrier on the ground, therefore allowing good ventilation under the shed.

The floor joists would be spaced 24'' apart hung with metal joist hangers and noggins into the floor frame. Would 2'' x 5'' pressure treated joists suffice?

I would use some form of insulation between the floor joists, preferably not polystyrene would attic style insulation suffice?

The floor will be moisture resistant chipboard tongue and groove (2'x8') 18mm thick.

Please blow holes in my floor method or suggest an alternative as it's fairly critical to say the least!!

The upright framing.
Pressure treated 2''x3'' for the bottom plates. All the rest standard CLS 2''x3'' timber.

What's the best way to fix walls to floor, large heavy duty screws?

The roof.
2''x5'' roof rafters cut with birdsmouths directly above the vertical studs, what I can't figure out is how I attach these to wall frames, is there special brackets that would be better than banging nails in all over the shop?

11mm OSB sheathing on rafters, now I would love to have the money for an EPDM roof, but I don't think I will with a grand budget, hence thinking Ondulain sheets, the roof pitch will be around 10 degrees if this makes any barring on what's best?

I would put insulation in the roof, maybe standard attic style to keep cost down.

The cladding inside to out.
9mm OSB as a cheap vapour barrier inside screwed/nailed to walls.

Insulation in the walls, more cheap wool stuffed in there?

Some basic membrane on the outside, any ideas?

Horizontal 1'' battens with 6'' vertical weatherboards with 1'' spacing and covered with say 2'' weatherboard strips, I like this style it looks pretty contemporary, or would I be better with bog standard feather-edged cladding. This I think will be the most expensive part of the build.

Windows and doors:
3 windows nothing fancy maybe some clear Perspex. Or some second hand glazed windows, if the budget stretch's!

Double doors of some kind on the short side of the shed.

As it progresses I will post pictures and I am working on a sketch up drawing, any advice is much welcome at this stage.

Thanks
Alan

 

[RobinBHM]

Foundation, 12 pads seem fine, concrete blocks is an alternative option. If your top soil is quite solid maybe cover the area with paving slabs, you could get them almkst free if they arr used ones on ebay. This will give you a base that is floating so could settle. If you dig down below the top soil a d create pads you may have a more solid basd but there will be greater pressure on each pad.


Just screw the rafters down with long screws.

Cromar 3 membrane?

Vertical T&G should be counterbattened, vertical first, then horizontal. Conventional cladding is therefore less work and cheaper!

Windows, what about some used upvc windows? Double glazed, cheap and often available. Even if the dg unit is misted up you could replace at a later date. Double glazed units are cheap if you can find a local manufacturer.

 

[yeungster79]

Foundation, 12 pads seem fine, concrete blocks is an alternative option. If your top soil is quite solid maybe cover the area with paving slabs, you could get them almkst free if they arr used ones on ebay. This will give you a base that is floating so could settle. If you dig down below the top soil a d create pads you may have a more solid basd but there will be greater pressure on each pad.


Just screw the rafters down with long screws.

Cromar 3 membrane?

Vertical T&G should be counterbattened, vertical first, then horizontal. Conventional cladding is therefore less work and cheaper!

Windows, what about some used upvc windows? Double glazed, cheap and often available. Even if the dg unit is misted up you could replace at a later date. Double glazed units are cheap if you can find a local manufacturer.

Foundation, 12 pads seem fine, concrete blocks is an alternative option. If your top soil is quite solid maybe cover the area with paving slabs, you could get them almkst free if they arr used ones on ebay. This will give you a base that is floating so could settle. If you dig down below the top soil a d create pads you may have a more solid basd but there will be greater pressure on each pad.


Just screw the rafters down with long screws.

Cromar 3 membrane?

Vertical T&G should be counterbattened, vertical first, then horizontal. Conventional cladding is therefore less work and cheaper!

Windows, what about some used upvc windows? Double glazed, cheap and often available. Even if the dg unit is misted up you could replace at a later date. Double glazed units are cheap if you can find a local manufacturer.

Thanks Robin, the back of shed line to the front of shed is sloped by at least 6'' so Im worried about the amount of digging and getting the dirt out of the back. Plus I can imagine that levelling 12 paving slabs over 14x8 would be a bit of nightmare.

Regarding the pressure on the 12 posts, with 4'' posts into the ground set in postcrete would this have enough load bearing strength? I dont plan on putting really heavy equipment in.

 

[Fitzroy]

Alan,

My experience of building my shed:
- Low cost and low effort are not comfy bed fellows. Where I have saved money it has invariably been at the cost of my own time.
- Unless you have a flat level and already paved area to put the building on the groundwork takes time and effort. My pal and I did (started) a shed at the time time, for his we did a concrete pad, for mine I did pier foundations (a bunch of levelled concrete blocks). Both were back breaking tasks that took multiple weekends.
- Vertical cladding is lots more effort than horizontal, more battening, and more complex detailing around windows, doors etc.
- EPDM, vs Torch on felt, vs onduline sheets, the costs were not massively different, for the roof on my 20'x10' shed the total cost of any option were within £50-75 of each other.
- Insulating is expensive, for my 20x10 pent shed the insulation materials (glass wool in floor and walls, and celotex in the roof) i'm looking at £300+. I'm insulating so that if I ever want too I could use the building as a garden office, ie for long time periods. My old shed is not insulated but working in there of an evening with the fan heater on and heavy jumper it's ok. You could change your wall design to. Cladding, battens, membrane, OSB, then joists. Leaving the inside open so you could insulate at a later date if you find it uncomfortable to work in it.

On some of your specific questions:
- For the beam sizes look at joist span tables. A 2x5 joist at 600m spacing the tables shows a max span of 2.1m . For your floor this may be ok as you have intermediate supports. For your roof this is undersized, you'd want 400mm spacing or 2x6 joists.
- I put nets between them floor joists with glass wool (attic) insulation. Concerned I may have created a perfect mouse home, but time will tell. Could have used polystyrene etc but was more expensive....
- I used 150mm M10 coach screws through the wall floor plate and into the floor frame.
- I fixed the roof joists by cutting bird's mouths and using 'truss clips'. Was probably overkill (the theme of my build), and I could have just nailed.
- 11mm OSB boards on a 600mm joist spacing and you will not be able to walk on your roof (well I wouldn't but I'm a larger chap), i'd be worried about snow load also (but I live in aberdeen).
- The lower the roof pitch the more risk of water penetration. You'll need to take a close look if onduline sheets are ok at this angle, if they are then the overlaps between sheets will be larger and you'll need more sheets. If you can't get a continuous sheet the length of your roof, with a 10° pitch i'd be worried about wind driven rain getting past the overlap.
- If you insulate the roof, with insulation between the joists, you should allow for a ventilated gap above the insulation. With 125mm joists and a 50mm gap, this is only 75mm of insulation, that's not much thickness for glass wool.
- Membrane, I used permavent eco (from ebay), seems fine.
- Use secondhand windows off of gumtree, search regulary and you can normally get them free/v.cheap. You need to do this upfront and start collecting them, you can then design your shed around them. If you design a shed and require a specific window size then you'll be paying through the nose.

Have fun with your build, looking forwards to the pictures.

F.

 

[skipdiver]

When i did my 9' x 8' storage shed, i dug holes about a foot deep, filled with concrete, then put 7 newton blocks on top bedded with mortar to level. I built a framework from 6"x2" tanalised and dropped it on the top, putting dpc underneath on top of theblocks first. 6"x2" will easily span 8ft and in theory you could get away with 6 pads, though i'd be inclined to do a few more to take out the bounce. I covered that in flooring chipboard, then built the walls straight off that. I used 2"x2" tanalised for the walls, with 2" insulation and boarded the outside with feather edge and the inside with MDF. Roof was 4"x2" sloping with 18mm OSB (11mm too thin IMO) and felted it. It wasn't meant to be used for working in, so i just built it fast and cheap for storing stuff. You could beef yours up a bit and 3"x2" CLS can be had for £2 for a 2.4mt length from Wickes if you buy ten or more.

It's not the most robust structure but it's way better than a shop bought shed and didn't cost that much to do. Could certainly be done in your budget. The other option is to buy a decent shed and beef it up yourself with boarding and insulation.

 

[SteveF]

I made a huge mistake when I extended my shed
original part I built with 4 x 2 trusses on edge (peak roof)
the extension in a fit of total brain fade I laid my 4 x 2 flat across the headers
what a screw up, I really to this day don't know why, as it wasn't part of my scribbles
extended part is flat roof and had already been sheeted before I realised my madness
ended up putting 4 x 2 below roof in the correct orientation to make an upside down T and used truss clips to strengthen
I now have a really low roof inside on half my shed, which now will give me a headache with ducting

my whole point of this is:
make a drawing and stick to the important bits
don't scrimp on roof timbers, the weight on top is quite substantial and even more so when loaded with snow


Steve

 

[yeungster79]

That's great info fellas, it's great to hear others stories where it went good/wrong etc..

I will incorporate all above into my plans. Good to hear I should go 2x6 on the floors and roof joists, be a right disaster if it snows like crazy and the whole thing collapses!

 

[yeungster79]

Changes required so far ..

Foundation
- Consider concrete piers with blocks - is the idea of burying 4'' posts in postcrete horrifying folk??

Floor
- 2x6 joists

Roof
- 2x6 joist on 600mm centres
- 18 mm OSB at least - although lugging 18mm sheets up would defo be a two man job!
- revise pitch to >10 degrees dependant on roof material for example Ondualin at shallow angles could be an issue

Insulation
- Going to be expensive, consider insulating inside walls in stages. Therefore prioritise the floor for example.

 

[Fitzroy]

Changes required so far ..
Foundation
- Consider concrete piers with blocks - is the idea of burying 4'' posts in postcrete horrifying folk??

Not at all, I like the idea, just don't be fooled into thinking it will be easy ;D Your approach was what I wanted to do, however the presence of mature trees and the potential for root damage meant I was not allowed to (under my planning permission, required as my house is in a conservation area).

Changes required so far ..
Roof
- 18 mm OSB at least - although lugging 18mm sheets up would defo be a two man job!
- revise pitch to >10 degrees dependant on roof material for example Ondualin at shallow angles could be an issue

I managed the 18mm on my own, my roof pitch is similar, I found I could stand the board on end leaning it on a roof rafter, then lift/slide it up on the roof, as the pitch was shallow it would not slide off, so I could then climb up and slide it into place prior to fixing it.

Changes required so far ..
Insulation
- Going to be expensive, consider insulating inside walls in stages. Therefore prioritise the floor for example.

That's the approach I have adopted.

With all these decisions, closer timber spacing, thicker OSB, etc you are adding to your cost though. My budget started at will not exceed £2k, i'm now approaching £3k having added electrics, nicer widows, larch cladding. The OSB floor is ugly so i'm toying with trying to source a secondhand real wood floor from Gumtree. To hold to your budget you'll need to be ruthless with your decisions.

F.

 

[RobinBHM]

4" stub posts is one way of doing it and will work fine, its a bit like doing a deck. I would suggest using a posthole spade and digging bar You need to go down far enough to get to hard ground and finish with a square bottomed hole.

http://www.toolstation.com/shop/Landsca ... ger/p55706

http://www.toolstation.com/shop/p48155

If you are nearer than 2 metres to the boundary dont forget you will have a maximum height of 2.5M from ground level.

18mm osb3 can be lifted onto a roof single handed, its not that difficult actually, if its a problem screw a batten across the rafter ends to slide the sheet up against. 11mm isnt suitable really for a flat roof or shallow pitch.

sometimes EPDM is available on ebay as offcuts or creased rolls, although Ive found they arent a lot cheaper unless you can obtain very close to the required size.

EPDM isnt that expensive, its £7.50+vat per sq metre for the rubber so your roof would be about £150 incl vat and delivery. that doesnt include glue of course and if you use the proper trims they are expensive so just use timber trims

https://www.rubber4roofs.co.uk/classicbond

 

[Fitzroy]

sometimes EPDM is available on ebay as offcuts or creased rolls, although Ive found they arent a lot cheaper unless you can obtain very close to the required size.

EPDM isnt that expensive, its £7.50+vat per sq metre for the rubber so your roof would be about £150 incl vat and delivery. that doesnt include glue of course and if you use the proper trims they are expensive so just use timber trims

https://www.rubber4roofs.co.uk/classicbond

+1

got mine from www.rubberroofingdirect.co.uk, used the 1.2mm stuff

 

[yeungster79]

To hold to your budget you'll need to be ruthless with your decisions.F.

That's it Fitz, I'd love to have beautiful larch go on the outside but I will have to reconsider this when I firm my plans and get the spread sheet on the go with actual timber prices, goanna be tough decisions then lol. I see your in Aberdeen, any recommendations on timber merchants in Scotland, it seems they all deliver within reason.

 

[Fitzroy]

Got all mine from cordiners, cheaper than anything I found on the internet. They were v helpful and good service.

 

[skipdiver]

You can get 18mm OSB in tongued and grooved 2' x 8' sheets, which is what i used. Much easier to handle.

Nothing wrong with 4"x 4" posts into concrete but i used blocks on piers because i had stuff left over from my workshop build.

 

[yeungster79]

Regarding general stud work - would 3x2 CLS be the cheapest suitable timber for the walls?

3x2 would give just enough room for insulation im thinking.

As this project goes on I have the urge already to make it bigger and more detailed!

 

[SteveF]

not a great fan of cls
but if cost is issue then so be it
I would aim for 4 x 2 if possible
I built my shed from western red cedar from saw mill in the hope it will outlive me (it was still wet when I got it, but surprisingly does not seem to have moved)
can get a bit more insulation with that extra 1"
also the header plates would be 4" instead of 3", just more to think about

Steve

 

[RobinBHM]

CLS is really mean in net size, Id go for 3 x 2 studwork if you can or 4 x 2 if you want to go properly strong, thats what I used for mine and am certainly pleased with the extra rigidity. Of course off the shelf budget sheds are only 32mm sq or 38mm square frame so a 3 x 2 cls or stud will be pretty strong. You will certainly end up with a shed equivalent to a top end off the peg jobbie.

Its worth working out your meterage and getting prices to compare. its also worth ringing around and finding out what stock lengths are available, as you dont want to spend ages working your cutting list out for 4.8 lengths, then finding your supplier has only 3.6's or 6.0 metres!

If you draw out a plan of the studwork frame, it should be possible to cut virtually 100% of your lengths straight from a cutting list. To do that you need to know the exact finished section size, 47 x 95 or 45 x 97 etc etc. Each supplier will be slightly different.

I did 4 x 2 framework with 18mm osb to the outside then covered with tyvek housewrap, when I got to that stage the shed was really well sealed, no draughts and the rain just runs straight off, and thats before the cladding goes on, so I think the breathable membrane is a great plus, much better than cladding straight onto studs.

 

[MARK.B.]

Not saying it cant be done but i think you will struggle to do the build for just a grand, all the little bits n pieces can soon add up , does your budget allow for electrics / sockets / lighting.

 

[yeungster79]

Hi Mark, your right it's going to be hard to do the lot for a grand, the electrics and wall and roof insulation will be phase 2 of my build, im not overly concerned about what I consider the workshop requirements just yet, my immediate requirement is storage space.

Measured out yesterday for expanding it to 14x10 and rough costing materials without cladding was around £750 thats just flooring, walls and OSB and 2x6 roof rafters with no EPDM or felt.

With time and money issues its going to be a phased build, in all reality it needs to be ready by April. So ill crack on with the floundations and floor once I have solid plans/sketch figured out, then order wood for walls and roof.

 

[Fitzroy]

I was just working out my costs to-date, see my thread for details. Your timber costs are similar to mine (prorated for size) £1050 for 20x10 build. My costs are for 4x2 and 6x2 timber, so if yours are for 3x2cls they may be a little high.

F.