Converting flat roof to warm deck

[olimain]

The flat roof on the rear extension of a Victorian 2 up 2 down I let has finally given up the ghost and is leaking. I had a roofing company round on Friday, and he recommended that we convert it to a warm roof by removing all the limestome chippings (there's 3 inches of the stuff up there!) leaving the existing felt in place to act as a vapour barrier, building a framework on top with 4x2 timber, 100mm of Kingspan and Wolfin COSMOFIN single ply membrane on top.

Cost for a 14sqm roof inc lead flashings where required, black PVC wood grain fascias, new guttering, waste clearance etc is £1910+VAT. (SW London)

Does that sound like the right route to go down rather than just re-felting and how does the cost look? I liked the guy and he comes highly recommended.


Edit to add - my other option is to re-felt without the warm deck buildup, remove existing, fix 3 layers inc drips/upstands etc coming in at £880+VAT. I'm swaying towards that as it's a rental to be honest...

Edited by olimain on Monday 16th January 09:51