Workshop design questions

[sasq]

Hello,

In preparation for building my new workshop in a few months in a new home, i have a fair number of questions i feel i should already know the answer too and would be glad of some guidance from you fine ladies and gents. Please excuse gross ignorance or simply not knowing the correct terminology

I am looking to build something around 7m x 4m based on and inspired by the fantastic designs by mailee and later carlsberg.

Floor:
My preference is not a concrete floor, too much digging for my back and i dont want to employ anyone. I am thinking of a pier and timber joist type system using 47x150 joists across the width each on 3 piers, hanging joists at right angles at 60 centers. I was originally expecting the joists and piers to be 1.2m apart however looking at http://www.e-lindsey.gov.uk/NR/rdonlyre ... Tables.pdf page 14 it seems to suggest i can get away with up to 2.77m, i bit far for my liking. 1.8 sounds reasonable. Does this sound reasonable?
Maybe a picture would help?

Planning Permission
I have a 4.5m gap between the side of the house and the boundary for the workshop. The other side of the bounday is a line of trees at the bottom of the neighbours propetry around 100 foot away. Do you think planning permission would be a problem?

Building Regs:
Likewise due to above, what type of building regulations am i likey to run into?

Electrics:
I am planning on following the Build a shed the Mike way for the walls, however what do you do about sinking sockets and electrics? Just take chunks out the rockwool?

Sound Proofing:
I am trying to balance price, thermal and sound insulation, with the preference probably on price and sound insulation. (pick 2) Do you think the rockwall is about the best way to go?

Thank you all in advance for your advice.

 

[Halo Jones]

Planning Permission
I have a 4.5m gap between the side of the house and the boundary for the workshop. The other side of the bounday is a line of trees at the bottom of the neighbours propetry around 100 foot away. Do you think planning permission would be a problem?

I have just been through this but as I am in Scotland it may not be relevant. Any outbuilding should be at least 5 metres from the dwelling house or will be considered an extension of the property and require planning permission. The boundary to the neighbours doesn't sound like a problem. I think the 28 sq m is OK as I think PP is only needed over 30. There are also height restrictions - I think it is 4.5 m for a pitched roof with 2.5 m at the eaves.

I would avoid PP if you can. I am now building my workshop in the cold and rain as it took 4 months to get my PP through.

 

[dh7892]

For the planning permission, have a look at the sticky post about planning permission, the planning portal is the place to look.

From memory, the size of your building (footprint) is not an issue from a planning permission point of view. It's the height that can affect that. (Unless you use up more than a certain percentage of your garden).

Given you have the gap between the workshop and the boundary, I think you should be OK for building regs too. For mine, because I was within the proscribed distance to a boundary, I was limited to 15 square metres footprint because I was building in wood. I could have gone up to 30 squared metres if I'd used non-combustible materials.

For the sockets, I just stuck trunking on the walls and used surface mounted boxes. I think this adds to the workshop feel and, as long as you are careful in your placement, they don't get in the way.

 

[Carlow52]

Since the spec thus far is silent on the actual wall and roof construction I will just make some general comments.

On the flooring I would consider using man-made joists, with an RSJ across the middle resting on one central support.
http://www.ilevel.com/floors/f_TJI_joists.aspx for example.

I am the first to recognise that in cash terms they are more expensive than the old 9 by 2 or what ever but IMO, especially when working on your own, they pay for themselves, especially with hanging brackets

If you order X number of them, they are all straight, the whole length is 100% usable and there is no waste. You simply wont get that with timber

If you cut 200 of 400mm wide noggins, they all fit

The I section makes insulation between then a doddle as you can rest rigid insulation, subject to span limits on the bottom flange

Sound proofing.

The timber floor may act as a big boom box at certain harmonics so consider making it extra rigid. The rsj will help here if u fix the floor to it.

On the walls I would run a double layer of 12mm plaster board slab and keep all services external so as to minimise holes for sound and heat loss.
On insulation I perfer the interlocking wood fibre type insulation to rock wool
eg


http://www.ecologicalbuildingsystems.com/?country=gbr

This range of product also helps with air-tightness and sound..
You need to consider where all opes are for sound vis a vis the neighbors

The timber floor must be ventilated so it needs to be airtight around the walls for sound and heat loss.

 

[sasq]

Thanks for the replies and help guys, sorry its taken me a while to reply back. The old move is taking more time than expected.

I think i do get away with PP however i would prefer to go above 2.5 meters to be honest, but not by much. The building regs will be the killer as i am within 1m of the boundary and really wont want brick.

The RSJ / Man made joists is interesting but i expect the cost would be more than getting a contractor in to do a concrete floor.