full timber extension planning?

[luke morris]

Hi, need some advice really, we have a conservatory to which we would like to take down and build a timber extension, would it require planning or would it come under a tempary building as such, would it need footings a meter deep or concrete slab for it to sit on.? Any help is greatly accepted

 

[frutbunn]

If you are putting up a similar extension ie conservatory that is exempt from Building Regulations you can do what you want for foundations, I've seen one built off a tarmac path before and the rain water pipe discharged directly into the cavity!
If it requires B regs or if you want to carry out the work properly then as a very general guide foundations should be 1m deep for clay type soils, (this assumes there are no trees in close proximity) and 600mm for sand/gravel type soils.
The slab foundations is actually a raft foundation, these will incorporate steel reinforcing bars and/or steel mesh, if it requires B Regs you may need an engineers design, although some BCO's will agree an over engineered design in lieu of calcs.

 

[^woody^]

There is no such thing as a temporary building in a planning context

There are "permitted development" rights, and this is a form of pre-approval for what would normally need formal planning permission. Google that and as long as you keep to the dimensions, you wont need to apply for planning permission.

Any extension attached to the house will need building regulation approval. The technicalities of that depend on several factors, and could be either a slab or strip foundations. It depends on your designer.

There are other potential permissions such as building over drains, party wall act, deed restrictions, that you need to check.

 

[luke morris]

The conservatory was built over a man hole by the looks of it. And has a damp course and bricks 1/3 of the way up.
What we wanted to do was very similar to the SIP style construction with osb and insulation with osb the other side. Flat roof. And timber cladding on the outside with weather proof membrane on it.

 

[^woody^]

Your water authority wont allow an extension over a manhole - you will need to move the manhole.

There is also the issue of a timber building on or close to the boundary, so you'll need to deal with fire safety/spread in the design

 

[frutbunn]

Your water authority wont allow an extension over a manhole - you will need to move the manhole.

This assumes its on a public sewer, if its a private drain this is OK providing it is fitted with a sealed cover, further investigation will be required to establish if it is private or a public sewer.

 

[^woody^]

Oh yes, good point. Although I can't imagine why there would be a manhole if its just a private section of drain - more common is the house connection to the shared run, but you never know.

 

[luke morris]

It’s already got a sealed cover on it inside the conservatory. The property had planning for a 2 bedroom bungalow to be built in the garden. It’s not going to be close to a neighbour. It is a shared line between three bungalows.

 

[frutbunn]

Oh yes, good point. Although I can't imagine why there would be a manhole if its just a private section of drain - more common is the house connection to the shared run, but you never know.

Not unusual at all on older properties pretty much the norm, even on some modern properties with shared drains its not particularly unusual to have IC's that branch into a main shared run rather than being constructed on the main run, makes it a bugger for finding the main run position and invert for found depths.

 

[luke morris]

 

[luke morris]

Where the pink play house is where the man hole is that’s been covered. Where the toilet joins the run from next door.

 

[frutbunn]

It’s already got a sealed cover on it inside the conservatory. The property had planning for a 2 bedroom bungalow to be built in the garden. It’s not going to be close to a neighbour. It is a shared line between three bungalows.

In that case its a public sewer, you will need to contact the water co.

 

[luke morris]

I just wondered what happens as it’s already built over?

 

[frutbunn]

I just wondered what happens as it’s already built over?

The conservatory would have been exempt from B regs at the time of construction, in any case the drain/IC at the time of construction would almost certainly have been a private drain, however the legislation has subsequently changed. The present construction has no bearing on any replacement extension.

 

[luke morris]

Might as well scrap that idea then really