Cost of complicated loft conversion.

[KatherineCam]

Hi! Has anyone done a complicated loft conversion which required change of a whole roof? I assume it is like doing mansard roof or some other complicated loft conversations - I am looking for a top figure.
We are totally removing our roof and putting a new one instead and installing to 2 bedrooms and a bathroom (about 35 sq.m.) We got two quotes so far and they are outrageous in our opinion - well above £100000 ( without VAT). I think for this amount you can nearly build a small house from scratch.
Would appreciate any suggestions on building costs...

We had one done on our terrace, adding a decent sized double and an ensuite, mansard and new roof position at the front (changing height of roof meant adjusting the pitch a bit). We paid a touch under £40k for the building work. Add on the bathroom suite, built-in cupboards, new carpets throughout, decorating etc and it came in at around £58k.

The above total included building regs, a surveyor's report for the neighbour and planning.

We're in London and did it all with a big specialist company so paid a bit of a premium for them to manage it all from start to finish.

thank you for your reply. Was it done long time ago or fairly recently?

Earlier this year, we locked the price in last year though. If you're London based and want a supplier I can pm you the details.

Anyone else can comment or give me a price of their equal complicated extension/conversion?
Thanks

We're having a fairly complicated one - hip to gable and a L shaped dormer which is effectively 2 separate dormers, bricked up new gable end, pitched roofs on the dormers so they're in keeping with the period house etc. (the expensive options!). It will be using the full 50 sqm allowed under permitted development and will add 2 bedrooms and a bathroom. Cost roughly £60k before supply of bathroom suite, decoration, carpet.

Hope that helps

Edit - including VAT

Not sure if this helps as it's not a final cost, but when we were looking at houses (London) we looked at one that needed a hip to gable loft conversion with one dormer, for a single bedroom with ensuite. Got a builder round to quote and he said £50k including VAT not including decoration. Obviously that's an approximate quote as we only needed it to work out if we wanted to offer on the house.

Thank you very much! This helps. I also wounder how big was difference in quotes for your projects? Some builders refuse flat to give us even an aproximate cost and take up to 4 weeks to come back with a quote while others quite happy to say how much it will be ( more or less). However after weeks of meditating over our drawings they all came back with quotes from £39 to £130. We got 5 quotes so far and they all differ massively. We are totally lost...

I think £130 is outrageous but £39 is crazy as well. But all of the quote have a difference of at least £10-£15 which is starnge concider they all base them on enegeenering and architect drawings and schedule of work. I understand why Chanel bag cost £3000 while M&S one cost £30 but why builders's quotes are so diffrent? At the end of the day plaster is a plaster and wooden beams would not warry a lot in price between manufactures.
Anyone had such experience?

We have had companies quote us vast amounts more for building work than small builders.

Is it clear what is included? Whereas it won't make 100k difference, cost and quality of materials, decorating, bathroom installation and boiler installation if neded, carpentry etc will make some difference.

this is the problem - we gave all of them same drawings that went to planning and building regulations. Our architect wrote a schedule of work so all of them had the same papers in front of them. We did not specify anything appart from ussing a flat roof tiles ( which is normal) and a few sockets and inset lights. I also may imagine that two builders that quoted 130 and 120 just have big companies and hence more expensive. However next quote came at £83 which is nearly £50 less than the first one...