How much to completely renovate house

[LizzieMint]

I know it's a bit of a how long is a piece of string question, but just looking for a vague idea.
Have looked at a house which needs completely gutting and re-doing. It's nominally a 5 bed, although only 4 are upstairs so would probably keep downstairs as reception room. It needs new windows, new kitchen, new bathrooms (2 and a downstairs shower room), conservatory replacing, all flooring redoing, single garage demolishing and rebuilding. It's about 2200 sq ft to give an idea of the size. Don't know about wiring yet, presume new boiler will be needed.
We're trying to get a vague idea of renovations cost in order to figure out how much it is worth offering (if at all).
We've estimated £70-80k, if anyone's done a project like this, how much did it cost you? Does that seem reasonable? In the SW by the way.

I think double that, but I am used to London prices! But seriously it's a large house and there's a lot on your list. Is it an old house? If so, you may be thinking about new double glazed sashes which for a house that size would be £££.

For a very similar property size/no of rooms, but in London - build cost incl prof fees but no decorative finishes, just build, min 110. That included rewire, new boiler & CH, new roof, replacing lathe & plaster ceilings & walls & some joists, plus moving some internal walls. SW ought to be less as lower costs of labour.

And even if it is 70-80K you then have to add VAT - so that makes it nearer 100K.

If it helps we refurbed a large 3 bed (though included a new roof) and:
Replumbed
Rewired
Re-ceilinged downstairs
Replastered everywhere
New skirtings
New windows
2 new bathrooms
New kitchens
New Bi-folds
Knocked down a wall and had an RSJ put in
Had all redecorated
Oh replaced old iron watermain with new piping.

So no rebuilding of garage.

Total cost just over £100K. Plus VAT. Oh and then add in £3k for new woodburner. We in essence re-build all bar the walls . It would have possibly been cheaper to knock the bloody thing down - but I love it, it is home.

Whatever any builder tells you - add 20% for going over budget plus 20% VAT.

Double glazing add 5 - 10 k depending on type of garden doors incl. Kitchen - ikea 2-4k incl fitting, german 10-15k, it all adds up, or comes down to your taste & budget.
Maybe take a builder around with you to guesstimate costs.

We're planning on doing something similar and have budgeted for £150-200k. Depends on whether you're doing it to sell or to live in. We want to live in ours, hopefully for a long time, so want to do things properly. Doing something up to sell is a lot cheaper as you can patch things up and make it look nice without spending £££ on boring stuff no one will see, like insulation or quality pipe work.

Thanks, all really helpful. The house isn't particularly old (1950s I think) but has been very neglected. It actually has reasonably ok double glazed windows, but I don't like the style of them. I don't think roof, plastering, central heating will need doing, although we may possibly shift some walls around. We're going to have another more detailed look around tomorrow. Would rather over budget and have some left!

NinaRose is pretty much spot on IME. Sorry.
4 bed Victorian detached, 230 sq m, loved but neglected for twenty years, had to be stripped back to basics inside and out. Sounds very much as you have in mind even down to the old asbestos-ridden garage for removal and replacement, double glazing (18K, not 5-10, normal stuff not sash or anything clever), demolition of old lean-to and building of proper tiled-roof sunroom, new kitchen, bathroom, shower room- etc, etc, you name it.
This was not bought as a renovation project as such, just a family house in need of updating - the sellers were perfectly happy with it and couldn't understand why we were even bothering with a full survey!!
We too were advised to think in terms of say £70/80K, but depending on what was found once work began. Now just finishing, and can hardly bear to add up final costs but getting very close to £200K. This is actual work, not high-end Grand Designs stuff, but does include configuring some interior walls. North West. Good local builder, very proud of reputation, work done properly, no corners cut because it was to be long term family home.
Double the estimate, add 10% for anything subbed, like double glazing, conservatory etc, add 20% VAT.
It's the VAT that is the killer.
Trouble is that it is very difficult to get a true figure you can work to, because many problems only become evident as work progresses, and then have to be dealt with. You may be lucky. You may have building knowlege/experience/contacts and can project manage. Or as pp suggested, for resale you may decide to compromise with short-term cheaper solutions.
Good luck.

In 2011 we took on a 'half-finished' project.....a (non-listed) thatched Georgian attached house if around 2200 sq ft that had been re-thatched and new oil heating installed within the past three years, but needed loads of attention to make habitable (it was unmortgageable when we took it on) and comfortable.

We -

Re-wired including hard-wired smoke alarms
Demolished an attached outbuilding that was in danger of collapse (and in which the stupid previous owner had chosen to install the new boiler!)
Built a new architect-designed kitchen extension (increasing total sq footage to 2500)
Reconfigured former annex to create open plan space
Put in three new bath/shower rooms
Re-plastered throughout
Laid new limestone/oak flooring throughout ground floor
Fitted hardwood double-glazed sash windows to front elevation
Fitted cast iron rads to most rooms
Re-landscaped the large gardens
Added french doors plus new internal doors & skirting to ground floor
Put in three new fireplaces
Re-decorated throughout

We used high-end fittings throughout (limestone flags, oak flooring, FE tiles, Hansgrohe & V&B) and whilst we admittedly did a lot ourselves (plastering, tiling, rendering, decorating), we spent just over £100k......

Agree that it always ends up costing more though - our architect was very optimistic in suggesting the extension would come in at £20-25k (for a vaulted-ceilinged space with custom double-height windows) when it actually cost around £40k.

We are also in the SW......

If it's an old house get the drains checked. There are lots of things that may not be evident from viewing, or even survey, but that will become so once you start working on the property, takings walls down, opening up chimneys etc. Always assume the worst and overbudget. If you're planning on living in the property as a family home, spend money on getting the basics done really well and save money on decorating, you can always repaint in posh paint afterwards.

About to do something similar on a slightly larger house but adding a kitchen extension to it. I'm budgeting £300k (in the SE near London).

I'd say at least £150k but realistically more like £200k.

Unless you are very good at diy and planning to do a lot yourselves and happy to live on the building site whilet it's being done to save money.

£80k won't go far.

We're coming to the end of a complete house renovation.
We've saved quite a bit on fees as I'm an architect & have done the plans, project managed, employed & co-ordinated the build.
Our budget was £120k & includes a small new studio in the garden.
We are in the NE so probably cheaper although we have gone for high spec fittings.
Ours is a large 5 bed Victorian semi, 2 bathrooms, kitchen, breakfast room, living room, dining room, family room, downstairs loo, utility & conservatory.
We have replaced the wooden sashes with new hardwood, doubled glazed sashes, new heating & hot water system, insulated & boarded out the roof space, re-wired the house and added new sockets, new lights throughout, new back door, rehung & repaired original front door, completely new bathroom, shower room & downstairs loo, new handmade oak kitchen & matching breakfast room units, new gutters, new water main, some re-pointing & repair of external walls, external re painting, new burglar alarm, fixed fireplaces (missing grates & fittings) & cleaned chimneys so we now have working fires, removed random sinks that seemed to be in every room, redecoration throughout, new flooring (carpets, porcelain tiles, rubber), new data/music cabling throughout and probably a few other things I've forgotten.
It's beautiful but it's been a hard slog, and studio isn't done yet (life and paying jobs have interrupted)

We went through a spreadsheet and estimated around £115k. I think the owners have an inflated idea of its value though so I'm not sure we'll get it at a suitable price anyway!