Interestingly enough a 20x10 shed is my project for this year. I decided to go the build it route rather than buy it, this was mainly driven by the fact that I live in a conservation area so required planning permission and hence plans. In having to draw a shed from scratch I ended up questioning really what I wanted, this led to how to build it, what it may cost etc etc. I ended up with a pent shed design, see attached pics, on a pillar type foundation.
I used sketchup to build the shed, from the foundation to the roof. This process enabled me to work out how I would build each of the elements and to realise that it was within my capabilities. It also means I have a pretty accurate cutting list which I sent off to a local timber merchant to cost up.
My current budget for the shed is:
Pillar Foundations £100 (blocks, gravel and weed control fabric)
Timber £900 (4x2 studwork, 8x2 floor joists, 6x2 roof joists, 18mm OSB floor and roof)
Larch Cladding £600 (this can varies massively but I have a local mill (bloke with a saw) in Inverness supplying this)
EPDM Roof: £250
Windows: £300 (I am making the frames myself but they are still double glazed)
Electrics: £600 (but I need a 70m long 6mm2 supply from the consumer unit to the shed, and then a local earth spike, and signed off by a sparky)
Total: £2750
You could easily knock £750-£1000 off this by going with a lesser grade of cladding, dialing back on the window design, going for felt not EPDM on the roof, and having an easier electrics install. My plan however is to have a shell that if I want to I can insulate, dry line, heat and turn into a full garden office/room at a later date.
I plan to do a WIP on this but work so far has been limited to removing a massive compost heap and taking bags and bags of crap to the dump!
Fitz.