What happens in London between Christmas and New Year? Quite a lot, actually. But for London housing delivery teams, the real story is not seasonal. It is regulatory. Awaab’s Law is now moving from a social housing headline into a London-wide compliance risk that directly affects new-build performance, handover evidence and post-occupation liability. 

The decisive shift in 2026 is this: overheating is no longer just a design comfort debate or a Part O tick-box. It is increasingly treated as an occupant hazard that can trigger legally enforceable response clocks. For dense, glazed, flat-led schemes across London, that changes how you design, how you commission, how you document and how you structure contracts.

Awaab’s Law is the management layer of building safety

London project teams already understand the Building Safety Act as the high-control system for structural and fire integrity. Awaab’s Law sits beside it, but targets a different risk surface: hazards experienced by occupants after handover.

In practical terms, Awaab’s Law turns repairs and maintenance into a compliance workflow with statutory deadlines. That matters for London new-builds because many of the recurring post-occupation failures are not cosmetic. They are performance failures: ventilation, thermal stability, condensation control, electrical defects, compartmentation gaps.

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2026 hazard expansion: why excess heat changes everything in London

Historically, the public shorthand for Awaab’s Law was damp and mould. But the operational direction is clear: the hazard lens expands through 2026 and 2027 to cover broader safety and health risks in the home.

For London new-builds, the most exposed category is thermal safety: excess heat and excess cold intersect directly with Building Regulations expectations, including Part O overheating mitigation. If an occupied home becomes persistently overheated due to glazing, solar gain, restricted purge ventilation or a flawed strategy, the landlord’s clock starts.

This is the London stress point: dense schemes, high-rise typologies, large façade glazing ratios and urban heat island conditions compress the margin for error. A hot flat complaint in 2026 is not automatically a comfort issue. It can become a hazard investigation that requires evidence, action and auditable timelines.

• Overheating trap (pre-Part O design legacy): older design assumptions can fail in hotter summers and higher internal gains.
• Restricted opening windows: safety-limited openings can undermine purge ventilation effectiveness if the strategy is not robust.
• Façade / shading delivery gaps: shading value on paper is meaningless if installed incorrectly or omitted through value engineering.
• Mechanical ventilation dependency: if MVHR or extract fails, humidity rises, condensation risk increases and mould can develop fast.

3. The hard-stop compliance matrix: timeframes override traditional DLP thinking

The disruptive element is not only what is in scope, but how fast the duty bites. These are no longer best-practice targets. They are enforceable response obligations that landlords must evidence.

Operational reality for London teams: if a hazard cannot be made safe inside the statutory window, the landlord may be pushed toward temporary mitigation, decant / alternative accommodation and immediate escalation routes. This is why developers are seeing tighter pass-through obligations in Development Agreements.

A practical way to view it is a compliance matrix that is now driving landlord operations and contractual negotiation:

Requirement	Timeline	What it means on a London scheme
Emergency hazard response	24 hours	Immediate mobilisation expectation; mitigation may be required even before root cause is resolved.
Significant hazard investigation	10 working days	Evidence-led inspection needed fast; ventilation and thermal performance data becomes critical.
Written summary to resident	3 working days	Documentation discipline: what was checked, what was found, what is the next action and by when.
Commence safety works	5 working days	Start work becomes a measurable trigger; supply chain readiness matters more than excuses.

4. The liability rift: why developers are being pulled into landlord clocks

For London developers delivering Section 106 affordable housing or build-to-rent (BTR) blocks, Awaab’s Law opens a contractual gap: traditional Defects Liability Period expectations often do not match statutory response deadlines. 

• DLP mismatch: reasonable time in a contract is not the same as statutory time in housing law.
• Pass-through risk: landlords will seek to pass 24-hour / 10-day / 5-day obligations down the chain to contractors and specialist installers.
• Evidence burden: without commissioning proof and as-built evidence, the landlord has weak defence when hazards are reported.
• Design responsibility pressure: overheating fixes are rarely small; if the strategy is wrong, remedial works can be invasive and expensive.

This is why the golden thread conversation is evolving. The thread cannot only prove compliance at completion; it must also help defend performance in use. For thermal and ventilation hazards, that means commissioning records, settings, and handover guidance that is actually usable by residents and FM teams.

5. London-specific checklist: what new-build teams should tighten in 2026

If you are delivering or operating London flats in 2026, treat overheating as a compliance risk that must be designed out and defensible post-occupation. The fastest wins are operational and evidence-based:

• Overheating strategy defensibility: confirm the assumptions (glazing, shading, internal gains, purge paths) and keep the evidence accessible.
• Ventilation commissioning pack: fan rates, balancing results, filter strategy, resident guidance and clear fault reporting workflow.
• Resident how to use guidance: if the strategy depends on user behaviour, the building must be usable and instructions must be simple.
• Fast-response maintenance routes: define who attends, how quickly and what constitutes emergency vs significant hazard.
• Contract alignment: if you are developer-side, ensure your downstream obligations can realistically meet landlord clocks.
• Post-occupation monitoring: trend heat complaints early; repeated complaints are a signal that the strategy may be structurally flawed. 

 

Key takeaway

In 2026, overheating is no longer a soft design issue. Under the expanding hazard framework of Awaab’s Law, it becomes a compliance risk that forces rapid investigation, written reporting, and safety works under statutory clocks. For London’s high-density new-build market, the winners will be the teams who can prove performance, not just promise it.

image: constructionmagazine.uk

Expert Verification & Authorship: Mihai Chelmus Founder, London Construction Magazine | Construction Testing & Investigation Specialist