Guide
What a new roof costs in London, and what changes the price
This guide does not give you a price per square metre. It gives you something more useful: the list of things that move the number, so three quotations can be compared to each other rather than to a figure from the internet.
Why there is no honest single figure
A per-square-metre price implies that roofs differ mainly by size. They do not. Two houses of identical footprint on the same street can differ by a factor of two or more, because access, covering, pitch, complexity and what is found under the tiles all differ. A published rate that ignores those is a number designed to win a phone call rather than to inform you.
What follows is the list of things that genuinely move a roofing price, roughly in order of how much they move it.
Access
Usually the single largest variable, and often a substantial share of the whole job. A detached house with space all round is straightforward. A mid-terrace with no side return, a pavement licence, and a scaffold that has to be built over a bay and around a tree is a different exercise entirely. Scaffold hire is also charged by period, so a job that overruns costs more in access as well as labour.
The covering
Natural slate, reclaimed slate, clay, concrete and synthetic all differ substantially in material cost and in how long they take to lay. Matching a discontinued or reclaimed product adds sourcing time and a premium.
Complexity
Every valley, hip, dormer, chimney, rooflight and abutment is a detail that has to be formed and made watertight. A simple gable-to-gable roof and a roof of the same area with two dormers, a valley and a stack are not the same job.
Pitch and height
Steeper roofs are slower and need more edge protection. A third-floor roof on a London terrace costs more to work on than a two-storey semi of the same area.
What is under the covering
Nobody knows the condition of the battens, the underlay or the rafter feet until the roof is stripped. A good quotation names a rate for timber repairs so that, if they are needed, the cost is a calculation rather than a negotiation while the roof is open.
Lead
Whether new lead is included at every abutment, valley and stack, or whether existing lead is being re-used. Lead is expensive and labour-intensive, and re-using tired lead on a new roof is a common way a quotation comes in lower than its neighbours.
What else is included
Guttering, fascias, soffits, chimney repointing, waste removal, making good inside. All of these are cheaper to do while the scaffold is up, and all of them are places where two quotations quietly differ.
The questions that make quotes comparable
- Is scaffolding included, for how long, and whose licence covers the pavement?
- Is all the lead new? At which details?
- What underlay and battens, to what specification?
- What is the rate if timber repairs are needed, and how will they be evidenced?
- Are ridges being bedded in mortar or dry-fixed?
- Is waste removal in the price?
- What is the payment schedule, and what is the deposit for?
- What guarantee is offered, on what, in writing, and who stands behind it?
Ask all eight of every roofer. The pattern of the answers will tell you more than the totals.
On deposits
A deposit for materials on a large job is normal. A large deposit demanded in cash before anything has been ordered is not. There is a separate guide on checking a roofer is legitimate.
Want someone to look at it?
An inspection ends with a written report and photographs, whether or not you go ahead with any work.