Extension Costs

tunnie1776

First up.... sorry! I know this has been done to death but I'm unable to find recent threads which also match what I'm looking to do, not sure I'd have the budget to do what I want so thought I would break it down, thanks in advance...

1) Knock down the rubbish conservatory we have (it was installed by previous owners), I had it insulated and radiator added but it's still poor. Replace Conservatory with a proper extension, no doubt new foundations and such, to the max size I can do without permission. (we are detached) - As you look out the rear of the house from living room, the garage is on the right it extends further back. The right wall of the conservatory, is actually the garage wall. The garage is on the side of the house, but is set back, so goes further into the garden than house. I would build up to the same line as the garage, so extension would be about 5m x 4m. The previous owners kept the double doors/windows (double glazed) into the conservatory from the house, I would save/reuse these on the end of the new extension to save bit of money.

Not looking for mega high finish, happy with flat roof with one of those small pitched glass things in the centre? Not sure what is cheaper, that or pitched roof. Happy to do painting myself or basic DIY, but zero building experience. So need everything building wise handled.

What would be approx cost of this? I'm based Surrey/Berkshire/Hampshire border area. (quite like work of Ex Army Builders I've seen locally)

2) I'd love to also part convert the garage, as this extension, would then make the outside normal door to the garage now inside the house. It's a single garage, I'd like to partition off maybe 60% of the garage for a play room for the kids, it would need the floor raising/insulating, the garage is only single skinned so fully insulated/breeze blocks? It's modern (2012 house build) and water-tight, I'd also look to add either pair of roof windows (small-ish) or main window in the garage wall.

I'd then replace double glazed door for a nicer internal door, to a new play room. Garage door would remain, for a small storage area.

What would be the rough cost added to my primary building extension? Given if they are on-site doing extension already, there could be some savings?

I suspect, via a new mortgage deal in Autumn I could raise 30-40k.

Thanks in advance :beer:

LandyAndy

You don't say how big the area is but my experience of a similar job involving some demolition, rebuilding on new foundations and slightly extending, and a pitched roof with Veluxes was about £1500 per square metre. This was about two years ago.

tunnie1776

Thanks for quick reply, as mentioned the area is about 5x4m for the primary extension build. Garage, well it's about 60% of a standard single garage.

minibbb

I'm in Sussex so not too far from you. We have a three bed semi and are currently have our extension built.
It's 6m across and 3m out. Involved knocking down a small extension on the kitchen which added to their work. Now has a pitched roof with two lovely wooden velux windows within and 4.2 aluminium bifolds. Ours involved ALOT of drainage work, moving soil stack and a manhole. He has also converted understairs cupboard into a cloakroom and is fitting a few radiators and internal bifolds. Price for the lot inc electrics and plastering is 45k in nice colourwash render. I shopped around and this was the cheapest quote and a superb builder.
With the kitchen , flooring and new boiler we are approaching 60k.

It will be more than you think it should be but material prices have shot up in recent months and the old 1200-1500 meter doesn't really seem to work out anymore!

Hope this helps

tunnie1776

Thanks. Was rather hoping £1.5 per m2 was still valid!