Advice - building conservatory

[unclegrouch]

Well it seems the done thing to ask here first

I have to do the footings & floor for a smallish conservatory soon & could do with a bit of advice from those that have done the job or know a bit about it

Approx 11' x 12' Victorian. Dwarf walls about 9 courses high, timber frame, dg panels & polycarbonate roof panels.

Questions ....

How deep should my concrete footings be

How deep for the concrete & sub base for the floor ? (type 1 ok ?)

I have no idea about damp course, any advice on that would be handy too

I am no builder but half competent with anything mechanical, so fairly confident I can get it right with a bit of advice & a mini digger for a weekend. My only real concern is the drainage pipework in the area, although I am hoping this will be too deep to concern me too much ?

Ideas on the quantity of materials needed would be a help too

thnaks ;-)

[steveo29]

ummm... if it was about pc's or bikes i could help. bit too late for me to be looking stuff up as i will get it all wrong.

[V12Les]

Conservatories come under planing permission now, they'll take your fees but very rarely come and inspect as most councils are under staffed in the dept.
If unsure of what type of foundations you need you'll need to dig an inspection hole along side the house.There is no point in digging down a meter for strip foundations if your house is built of a Raft.Find that out first then accurate advice can be givin. To comply with Building Regs Re the floor you need dig down to allow for: Min 150mm scalpings, 100mm insulation, 100mm concrete and a min 55mm screed to finish floor level(FFL), which should be approx 25-40 above the house Damp Proof Course(DPC).As a rule when you dig down, if you can make an impression in the clay with you thumb...keep digging.
Hope thats of some help.

[unclegrouch]

Thanks for that guys, will look into it a bit deeper. Planning i was under the impression that any cons under 50 cu. mtrs was exempt ?

[TonupS2]

I think you will find that the general rule is that if its terrace house then you will be allowed 50m3 extension or conservatory on the rear under permitted development rights (or 70M3 semi or detached) If it's a big house then you can work on percentage volume of house. Any previous extension will use up all or part of the allowance. To clarify things speak to your local planning department Duty Officer. Building Regulations is a different matter and is concerned in the method of building. Until recently you did not require building regulations approval for a conservatory built at ground level and under 30m2 in floor area. It should not prevent ladder access to a room in the roof. The conservatory should have separation from the remainder of the house (doors) to reduce heat lose and separate heating zone control. I believe any electrical installation would need to comply wih the requirements of the building regulations likewise glazing safety (part N) this will be safety glass in vunerable areas etc. Again speak to your Local Authority Building Control Department for clarification as these things are allways and often being changed.

[a boardman]

Planning regulations have all changed and even if you have had a previous extension (with planning permission or built under PD rights) you may not need planning for a new extension.

A conservatory must have doors between the main house and the conservatory otherwise full building regulations will be required,
and heat loss calculation in a glass structure are a pain to do.

[jas xjr]

it might be a good idea to incorporate underfloor heating , wet or electric whilst you are digging up the floor anyway

[TonupS2]

For Building Regulation they define a conservatory as being an extension to a building which has not less than three quarters of its roof area and not less than half of its external wall area made from translucent material and is thermally separated from the dwelling by wall, windows and doors. As A Boardman noted I think new planning legeslation was brought out 4 days ago, which may ease planning restrictions (although I have no idea of the new rules), best check with planning department.