Buying with a view to extending/remodelling - how do I know what I envisage is architecturally and financially feasible?

[cavell]

There isn't that much property available in the area where we would like to live.

One possibility we have seen is a bungalow on a largish plot which could potentially be great if we could add an upstairs with 3-4 bedrooms and re-jig the downstairs layout.

But how can we work out how much this sort of thing would cost? Or whether it would even be possible to add another floor to the bungalow? I understand that the foundations would need to be checked to see whether the structure could support a second storey, yet I don't see how we could do that before we actually own the place.

I have conjured up a ball-park figure of £150k to do the work (South East). Does that sound remotely plausible?

Do we just have to buy the property and hope for the best?

I would ask a builder to come round with you and give you an estimate. I'm sure the vendors would be happy to accommodate. Do you know any architects?

Are there many other similar bungalows in the area? If so, a good start would be to check whether any others have been extended in the same way. If they haven't, that suggests there's a reason (planning authority being awkward? shallow foundations? excessive cost of the work involved?). If they have, a bit of cheeky door-knocking could get you a quick answer to your question.

Where we are in Winchester there are a lot of bungalows that have had this done, although with varying degrees of success - some are nice, but others have ended up with very strange layouts, and some are complete eyesores that have struggled to sell.

From our plans for a fairly small two-storey extension and remodelling the rest of a 4 bed house, £150k sounds a bit optimistic for adding 4 beds plus other structural work. But I agree asking a builder would be worthwhile.

I guess I thought it might seem somewhat presumptuous, turning up with a builder to a house I don't actually own.

(The house is a "one off", so I don't have the option of taking to the owners of similar houses).

Bungalows don't normally have proper roof extensions like that. One or two bedrooms are added. I don't know why, but there might be some buildery reasons. My friends have bought a bungalow on a large plot and are knocking the whole thing down and starting again. That might be more of a plan for you. You can also apply for planning permission even if you don't own the property, but a better idea would be to ring the planning office and see what they say, and then ask the building control people if they had knowledge of building big roof extensions on bungalows in the area.