New Build RoofingIssues & Checks 2025

New build properties in Southampton — the large developments around Hedge End, Fair Oak and the city fringe — are covered by the NHBC Buildmark warranty for 10 years after completion. This protects buyers against major defects but does not mean new roofs are defect-free at handover. This guide covers what to check at snagging, what the warranty covers, and what to do when cover expires.

Common Roofing Defects on New Builds

The most common roofing issues on new build properties are: ridge tile mortar applied too thin or in the wrong mix (fails within 3 to 5 years rather than 20-plus), lead flashings not properly dressed at abutments and chimney junctions (leaks in the first few wet winters), flat roof upstand heights below 150mm on extensions (allows water entry in heavy rain), and Velux window flashings not correctly integrated with the tile profile.

The NHBC Standards set the workmanship requirements for new-build roofing and underpin the 10-year Buildmark warranty on defects.

Source: NHBC Standards

What to Check at Snagging

At snagging or during the 2-year defects period, check: ridge tiles are firmly bedded and not rocking, lead flashings lie flat against the roof covering without gaps, gutters are correctly sloped with no standing water, fascia and soffit boards are fully fixed with no gaps, and any flat roof upstands meet the minimum height. Documenting defects in writing within the defects period is critical for warranty claims.

NHBC Buildmark — What it Covers

In years 1 and 2 the developer is responsible for remedying defects. In years 3 to 10 the NHBC warranty covers major structural defects — defined as physical damage affecting stability or habitability. Cosmetic defects and normal maintenance requirements are not covered after year 2. A leaking roof caused by inadequate flashing specification falls into a grey area — it may be covered in years 3 to 10 as a defect, or the insurer may argue it is a maintenance issue.

After the Warranty Expires

When the Buildmark 10-year warranty expires, the property owner is responsible for all maintenance and repairs. On a 10-year-old new build in Southampton — properties built in 2014 to 2015 are now at this point — ridge mortar on the original build may already be showing early signs of failure, and any poorly-specified flashings should be inspected. We carry out post-warranty surveys on new build properties specifically to identify any issues before they become larger problems.

Last reviewed: 20 July 2026 by Southampton Roofing Experts