BSA 2022 · Principal Designer

BSA 2022 s.135 — what principal designers need to know

Reviewed by Matthew Bartlett, Director, Apex Insurance Brokers Limited (FCA FRN 724952) · Published 15 July 2026

Building Safety Act 2022 section 135 amended the Defective Premises Act 1972, giving Higher-Risk Building (HRB) owners a 30-year retrospective claim period and a 15-year prospective claim period against principal designers.

The 30-year retrospective window

Before BSA 2022, the Defective Premises Act 1972 gave 6 years to bring a claim from completion. Section 135 amended that section for HRBs specifically.

For HRB work completed before 28 June 2022, the retrospective claim period is 30 years. This means claims can be brought today for work completed as far back as 1996.

For HRB work completed after 28 June 2022, the prospective claim period is 15 years.

The 'HRB' definition is critical: buildings 18m+ or 7+ storeys containing dwellings.

PI cover implications

Standard PI is claims-made — cover responds to notifications during the policy period only.

A firm needs continuous PI cover for the full retrospective liability period, including run-off, to be responding to claims.

This makes gaps in cover between 1996 and now genuinely material.

What principal designers should do

  1. Audit which projects are HRB in scope.
  2. Verify PI retroactive date covers earliest HRB work.
  3. Consider aggregate limit sufficiency given multi-project exposure.
  4. Discuss HRB-specific extensions or exclusions at renewal.
  5. Where the firm has ceased, ensure run-off is in place.

Frequently asked

Does s.135 apply to all buildings or just HRBs?
Just Higher-Risk Buildings: 18m+ or 7+ storeys containing dwellings. Non-HRB work reverts to the standard Defective Premises Act 1972 6-year window.
What if my firm didn't work on HRBs?
Then s.135 doesn't apply. Check whether any past project has since been reclassified as HRB — the definition captures buildings built for other uses that were later converted to residential.
Do I need special PI for HRB work?
You need PI that responds to HRB claims. Some insurers now exclude HRB work explicitly. Check the wording at renewal and negotiate the position.
How does retroactive date interact with s.135?
Your PI's retroactive date determines whether claims from older work are covered. For a 30-year retrospective window, you need a retroactive date that extends to when the work was done.
What about principal contractors?
s.135 also applies to principal contractors under the same building safety framework. Principal contractor PI carries the same 30-year retrospective exposure.
Should firms who never do HRB work still care?
Only if there's any possibility past work is now HRB-classified. If certain the firm has never touched HRB, s.135 doesn't reach you.

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Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority. Firm reference number 724952. Registered in England and Wales, company number 07014570.