Two storey extension or single storey plus loft conversion - which is cheaper?

[united4ever]

A)Single storey side extension (40 sq metres) and a loft conversion with one dormer.

B) a two storey side extension (40 sq metres downstairs and 20 square metres upstaitrs).

Option B gives us the chance to do the downstairs work now which is a priority and do the loft later as the kids grow older. Option A would require us to wait a few years to afford what we really want.

Option A would also likely mean losing the box bedroom so it would remain a 3 bed house (albeit 3 doubles). Option A would also mean we could our garden does not get cast in shadow in the morning which Option B would. Option B would make it a 4 bed house.

Option B is the better one isn't it but could be years before we can afford it. What would the price difference likely be - would the two storey work out similar to single storey and a loft conversion? We are in the North West.

We were just in more or less the exact same position and when we looked at cost v's disruption and argued over it for 9 months we have decided to put our house on the market and pay the extra money on something already done! Massive decision and still not entirely sure it's the right one, but nothing ventured nothing gained!

I know that's not very helpful, but I feel your pain!

Do you have details of your layout now? I'd have thought there wouldn't be that much of a difference between the cost of the extra space upstairs, or the loft conversion. How big is your box room? I think it may impact on the value after the work though, depending on the size of the room that you lose if you do the loft conversion. I think in our area (i remember you're not too far from me), 4 beds will generally command a higher price than a 3 bed, even if the 3 beds are double.

A lot of loft conversation companies also do extensions. Why not give one a ring and get them to come round and look at what's possible?

I would have thought double extension would be cheaper, but I'm no expert. I reckon you'll need planning permission.

We are coming to the end of our 2 storey extension at last. We had the single/double storey debate for 3 years, and in the end it made more economic sense to just do the double.

As we are working to a very tight budget, the builder is just leaving it after he has plastered it and we are doing all second fix work ourselves. I would say to build the double storey but perhaps stagger the finish. So make the extension watertight then slowly finish it yourselves - would this be an option?

We are NW as well so feel free to pm if you want builder recommendations.

as attached pics :). Not got the current house measurements to hand but it's small 72 square meters I believe total. The 2 storey extension would add 60 sq metres or just the ground floor would add 40 sq metres. Yeah box room is tiny too and has a boiler in a cupboard in one corner which basically means you can only have a single bed but no desk or wardrobe. Not such an issue now since my son is only 7 and we have fitted wardrobes with enough storage in the other two bedrooms but not ideal.

Thanks again :)

Don't forget that if you go up to a 3rd floor you start having regulations around fire alarms and fire exits (fully enclosed escape routes and wired in fire alarms if I remember rightly), which could be a real pain in the bum (this is what put me off a loft conversion).

I don't think that if you extend without adding a room you will see your money back. no matter what you decide, getting a quote for both is a sensible idea. I would get the boiler out of the box room and fit it either in the loft or on the ground floor.