Why do roof replacement quotes vary so much?

Start with the published range. Checkatrade's roof replacement guide, updated October 2026, gives a UK average of around £8,000 and says most jobs fall between £4,000 and £19,000. That is a spread of £15,000 before anyone has looked at a particular house, and it is the honest background to any comparison.

The same guide breaks the average down by roof shape. Its table, headed as plus VAT, shows hip roofs at £9,250 to £18,000, gable roofs at £7,000 to £16,250 and flat roofs at £2,800 to £7,500. A hip roof has sloping ends as well as sloping sides, so it has more ridges, more cuts and more labour than a plain gable.

These are typical national figures, not prices from us. A written quote follows our survey of your roof, at one total price.

Two firms can quote on the same roof and mean different roofs. Concrete interlocking tiles, clay plain tiles and natural slate are not interchangeable in cost. Checkatrade's slate guide, last updated September 2026, puts a slate roof at £160 to £210 per square metre, and the choice of material alone moves a quote a long way.

Specification matters just as much. A firm that fixes ridge and hip tiles mechanically, as BS 5534 has expected since its 2014 revision, is doing more than one that simply beds them in mortar, and a dry-fix ridge system built to BS 8612 goes a step further again. The underlay, the battens, the lead around the chimney and the eaves ventilation all differ between a careful job and a bare-minimum one, and none of them shows from the pavement. Two quotes can look similar on the doormat and describe quite different roofs once the tiles are off.

Ask each firm to name the covering and the fixing method on its quote. That tells you whether like has been priced against like.

Many gaps come from what is left in or out. Checkatrade gives a typical scaffold cost of £700 to £1,300 for a roof replacement, and its roof tables carry a plus-VAT label, with VAT at the standard rate of 20% on gov.uk. A figure with both inside it is a very different offer from the same figure with neither, and the gap can be wide before there is any real difference in the work.

So look at whether VAT and scaffolding sit inside each figure. Ask too whether waste removal is covered, and whether the Building Regulations notification is dealt with where the work needs it. A re-roof does not always need an application, but one can be needed depending on how much of the building envelope and the roof is affected, and the firm should tell you which applies to your house.

Each of these is a plain yes or no that you can ask. None of them needs a breakdown of how a price is built up.

The widest gaps are often between a quote written from the pavement and one written after going on the roof. A price given from a photograph or a phone call has to cover what nobody could see: rotten battens, damaged rafters, a failed valley, old felt that crumbles in the hand.

A firm that guesses low will add to it once the tiles are off. A firm that guesses high is covering itself against that. Neither is helping you. We do it the other way round: a survey on the roof itself, pictures of each fault, a plain repair-or-replace verdict, and only then a written quote giving one total price. Our answer on replacing roof timbers during a re-roof explains how hidden damage is handled.

Be wary of a figure that arrives without a visit, particularly one pushed on you at the door.

You do not need to become a roofer to read a quote. You need the same few answers from every firm.

• Which covering, by name, and which fixings?
• Is VAT in the figure, and is scaffolding in it?
• Who removes the old roof and the waste?
• What happens if rotten timber is found once the roof is open?
• Is the start window written down?

If two quotes still differ widely once these match, the lower one may leave something out, or the higher one may include more than your house needs. The number of quotes worth collecting is covered in our answer on how many roofing quotes to get, and our scaffolding answer shows the scaffold side. The wider picture is on the roof replacement and new roofs page.