NHBC dismissing British Standards BS 8203 SR1 requirement for LVT floor - builder refusing full rectification. What are my options? (UK New-build)

Hi all,

Looking for advice on a dispute with my new-build developer & NHBC over defective flooring.

I moved into a new-build in July 2025 and paid ~£5k for Amtico Spacia LVT. After moving in, I found multiple areas of the screed exceed NHBC’s ±5 mm over 2 m tolerance. The builder never carried out a proper measurement, and although their Construction Director admitted in writing that areas exceed tolerance, they still refuse full rectification.

Key technical issue:
Amtico Spacia is a thin LVT (2.5 mm). Under BS 8203 (6.2.3), thin resilient flooring must be laid on an SR1 substrate (±3 mm). Amtico’s own guidance also requires a smooth, even subfloor, and NHBC 9.3.7 states flooring must follow manufacturer requirements and British Standards. This is also a requirement for the manufacturers warranty.

NHBC position:
They’ve told me informally they won’t consider SR1, see ±5 mm as “guidance,” and may side with the builder under the “proportionate” clause (9.1.1), even where deviations exceed tolerance.

So NHBC appear to be dismissing both BS 8203 and manufacturer requirements, despite referencing them in their own standards.

My questions:

1. Can NHBC legally ignore BS 8203 and the manufacturer’s specification?
2. If NHBC side with the builder, do I have civil options for claiming the screed isn’t suitable for the chosen finish?
3. Would a court be more likely than NHBC to apply the British Standard?

Any advice or experience appreciated.

Thanks.