Extension question.

Hi,
We are thinking about adding a 4m extension on the gable end of our 1930s 1½ storey end terrace house. We're having some "animated discussions" about whether to go for a single storey extension or the full height.

We're doing this with a tight rein on the budget, up to wind/watertight would be done by known good tradesmen, the rest by ourselves. We reckon the shell should be well under 20k.

In an attempt to settle our arguments, what is the most expensive part of the build?. I reckon that the money is in the groundwork and roof, the bit in between is basically just some extra blocks and timber.

Thanks,
Mags.

Ground work can be unpredictable and costly.

First floor joist detail slows the job down slightly and is another cost factor as is any lintel installation.

Scaffold?

Windows?

The roof, logistically is the most difficult and is on par with the groundworks.

But all works up to dpc, i.e. trenches, concrete pour, slab, foundation masonry, drainage, ducting etc, is probably the highest cost.

But don't underestimate the cost of furnishing rooms, particularly kitchens, bathrooms and utility rooms. A high spec' kitchen can cost as much as the extension!

Thanks for that, it's pretty much what I was hoping to hear!.