New roofs

What hidden costs can arise during a reroof?

Short answer: Common unknowns include rotten decking, damaged rafters, unsafe chimney masonry, undocumented insulation and extra layers beneath the covering. A good quote explains allowances and variation rates.

What this means in practice

A reroof is a complete weatherproofing system, not simply a new layer of tiles. The quotation should join up the covering, underlay, graded battens, ventilation, insulation, ridges, verges, leadwork, timber repairs, scaffold, waste and compliance route.

What to check next

  • Ask what can only be seen after stripping
  • Set approval rules for variations
  • Hold a sensible contingency rather than assuming zero extras

When should you ask a roofer to inspect it?

Ask for a full roof survey when defects are widespread, repairs keep moving from one area to another, the underlay is failing or the cost of repeated access is becoming uneconomic. The roofer should show why replacement is justified and separate confirmed work from hidden-work allowances.

Safety first: do not climb onto a roof without suitable access, training and protection. Keep clear of loose coverings, unstable ceilings and water near electrical fittings.

Technical content reviewJ & L Welch Roofing & Paving Services Ltd · Over 20 years of combined roofing experienceReviewed 28 August 2026 · How our answers are produced

Would you like a property-specific answer?

Request an inspection and written quotation from J&L Welch.

No deposit is required. Payment is due on completion within seven days, with the agreed scope and price confirmed in writing.

Request a quotation