How do I cost up a renovation?

[edgeware]

I have had my head majorly turned by a 1930s property that would require modernisation. It looks liveable and well maintained. 2,750 sqf. Estate agent has mentioned the roof needing work, and rewiring needing to be done. It would also need bathrooms/kitchen doing, insulation, double glazing, etc. However, no extension needed.. Possibly knocking out one wall.

I see that the general advice at the moment is to aim for £2,000 per sqm if costing up an extension, does the same go for a renovation?

Has there been an offer on it before,so maybe a survey has been done?

It's unusual for an estsrd agent to mention repairs as they are usually keen to avoid big ticket items such as roof.

Really tricky to say because so many factors but honestly will be way more than you think.

Repairing roof could be £20-40k, hopefully timbers are OK and don't need replacing which is why there is a range. You'll need to insulate, add 5k.

Rewire - new consumer unit is at least 5k and then sockets are typically costed at £100. You can easily spend 10k on electrical.

Windows - basic Windows and front door, assume 10k.

Plastering the whole house - £250 per day
New internal doors, £200 for supply and fit
Gas - £10-15k
Kitchen - whatever you choose but not often less than 15k plus fitting £5k at least
Bathrooms - at least 5k but main bathroom more like 10k
Flooring- might need prep before hand - latex is expensive.

If wall down then you need building regs and steel calculations. 2k for fees then cost of the work.

What's the house value and where is it? South East builders costs are now almost double that what they were a few years ago.

Thank you so much @Fireflygal I appreciate the knowledgable response... The house is priced to reflect the fact that it needs modernisation, which is why I think the estate agent mentioned roof, wiring. That is a good point about the survey, I will ask. Maybe people have backed out before which is why it is still on the market.

The house is South West. I am guessing that if estimating a renovation could quickly come to about 150,000 at least. It is currently on the market for 800,000 but has not sold at that price.

Whatever figure you come up with, add in about 50% for things you’ve forgotten, things you didn’t know you needed, things that get broken or that don’t work out as expected, I hinge that need redone by someone else and rising building materials and labour costs as well as just general contingency.

If it’s a long project then doubling it isn’t ridiculous at the moment.

Consider rental costs as well as you can't really live in it.

Also factor in driveway and patio costs. That alone can be 50k if it's a decent size driveway & garden. Fencing alone would be £200 per panel at least.

Any conservation considerations?