All the online guides assume ground floor.

We have single storey kitchen and utility. Built 15yrs ago and apparently designed to have second storey added. Timber frame and rendered block.

We would like to add a bedroom to there. 3.5x5m, one door in (where there is existing window), two standard size uPVC Windows of about 2m(w)x1m(h).

We need a new roof anyway. Seems the time to look at this.

Approximate cost? I’m thinking £1.5k/m2, plus fees. Ideally a design and build as I don’t think it needs a full architect design.

Treble that guesstimate…

And not until the Spring Mate, we’re really busy and can’t fit it in.

#sucksteeth

And not until the Spring Mate, we’re really busy and can’t fit it in.

Triple that guestimate as well.

£40k

I’ve just done a extension to a 2×2.5m bedroom taking it over the garage to be a 3.5×3.5m room (biggest planning would allow given boundaries).

30k nearasdammit.

We extended doubled the size of 2 3×3.5 m^2 bedrooms this summer over the top of the utility room and garage.

The build cost £28k and fees were £4.5k.

And if the extension is 15 years old, will the work done then meet current regs. now in respect of footings depth etc when putting more on top?

Yes the laws of physics are the same as they were 15 yrs ago.

Are the buildings regs though?

Yes the laws of physics are the same as they were 15 yrs ago.

Are the buildings regs though?

^^^ Exactly – are regs. on things like footings depth etc the same or would they need to be upgraded?

Do you have the plans from when the extension was built as you may need a structural engineer to verify what’s there is actually OK to build on top of.

to me the issue to be concerned about is the timber frame, to build over this you’ll either justify that the timber frame can support the additional loading or construct the first floor so that no additional load is imposed.
the last extension of this type I built, the timber frame was removed and replaced with a blockwork inner leaf