What should I ask if a roofer recommends complete replacement?

Replacement is the right recommendation when failure is general rather than local — fixings corroding across the roof, battens and underlay at the end of their life, or a covering that can no longer be re-fixed. Each of those is a finding, and each can be shown.

So ask: which of those applies, and what did you see that establishes it? An answer about the roof's age is not evidence about its condition.

There is usually a middle option. Repairing one elevation. Renewing failing details. On slate, a strip and re-lay that renews battens, underlay and fixings while reusing sound original slate.

Ask why each is unsuitable here. A contractor who has genuinely considered them will explain; one who has not will restate the recommendation.

On a slate or handmade tile roof, this question has real financial weight. If much of the covering is reusable, a strip and re-lay may cost significantly less than full replacement and keeps the building's appearance.

Ask what proportion is reusable and how that was assessed. Vagueness here often means the assessment was never done.

For work of this scale, a second inspection is proportionate. Ask the second contractor to inspect independently rather than commenting on the first quotation, so you get a fresh diagnosis rather than an anchored one.

If both, working separately, find the same general failure, the recommendation is well founded and you can proceed with confidence.

Once replacement is agreed as the right course, the written scope matters: coverings, battens, underlay, ridge and verge system, flashings, access, disposal, programme, payment stages and the guarantee.

Take the time to compare scopes. Replacement is the largest roofing decision most owners make, and a few days spent testing it costs nothing.