The Dormitory Deficit: Who Houses the Builders of a Third Runway?

As of November 2026, the argument over Heathrow expansion is still too often conducted at cruising altitude: passenger demand, carbon budgets, airspace modernisation and the national interest. All of these matter. But beneath them sits a more granular question that will be settled at street level long before any new runway opens. Where would the construction workforce sleep?

That question is not a technical footnote. It is a local impact issue with a timetable. A major expansion project would require thousands of workers over many years, and those workers would need beds, bathrooms, parking spaces, waste collections, GP registrations and places to buy a pint. If the accommodation is not planned, conditioned and delivered in sequence with the works, the demand does not disappear. It is displaced into the private rented sector, into houses in multiple occupation, into the spare rooms and short-term lets of Hillingdon, Hounslow, Slough and Spelthorne. The result would be a housing shock before a single plane has moved.

A campus is a promise, not a plan

Promoters of large infrastructure projects have learned to speak the language of campus-style worker accommodation. The image is reassuring: purpose-built units, managed occupancy, shuttle buses, a controlled footprint and a clear exit strategy. In principle, this is the right model. Concentrated, well-managed accommodation is preferable to scattering a temporary workforce across already stretched housing markets.

But a campus is not a planning outcome. It is a proposal with conditions attached, and the difference matters. The questions are practical. Is the site identified? Is it consented? Who owns it? Who manages it? What occupancy rules would apply? Would it be tied to the commencement of construction, or could works begin while the dormitories remain a rendering? What happens if the site is delayed by contamination, access disputes or local opposition? What happens at decommissioning, when the workforce shrinks and the site must be returned to another use?

Planning reality has a habit of arriving late. A campus that is promised in a development consent order but not conditioned to be operational before enabling works begin is not a housing strategy. It is a press release. Residents are entitled to ask for a housing trajectory that sits alongside the construction programme, not a vague assurance that workers will be accommodated somewhere.

The HMO pressure point

Houses in multiple occupation are the flexible housing stock of the private rented sector. They can provide affordable rooms for mobile workers, and many are well run. But they are also the point at which construction demand meets local housing need. In wards around Heathrow, family homes are already under pressure from letting to sharers, and councils have used additional licensing and Article 4 directions to manage conversion. Those powers matter, but they require enforcement capacity.

If a worker campus is delayed or undersized, the market will not wait. Landlords will respond to demand. Some will convert properties lawfully; others will not. Overcrowding, waste, parking and fire safety risks can follow. A worker village that is not built is, by default, an HMO expansion that nobody has planned. That is the dormitory deficit: the gap between the housing the project promises and the housing the local market actually supplies.

Councils should therefore ask for more than a campus commitment. They should ask for a cascade: what happens if the campus is not ready, what happens if occupancy exceeds projections, and what enforcement resources would be funded to deal with the private rented sector consequences. A commitment without a fallback is not a plan; it is a hope.

The private rented sector as shock absorber

The private rented sector is not spare capacity. Vacancy rates in west London and the Thames Valley are thin, and rents have risen sharply in recent years. An influx of temporary construction workers with housing allowances would not create new homes. It would compete for existing ones. Landlords may prefer short, high-yield lets to local families on lower incomes. Tenants may face renewal pressure, eviction risk or a move further out.

The effect would not be uniform. It would be felt most acutely by renters on modest wages, by people in temporary accommodation and by households already at the edge of affordability. Construction workers are not the villain of this story; they are workers doing a job. The villain is a planning system that allows a major project to externalise its housing demand onto the least secure parts of the local market.

Services under strain

Housing is the most visible pressure, but it is not the only one. General practice lists, urgent care, waste collection, water infrastructure, policing and public transport all have finite capacity. Construction workers may be relatively healthy, but they still register with GPs, use roads and generate waste. The impact is not only a question of total numbers; it is a question of timing. Peak construction would overlap with existing shortages, and local services would be expected to absorb the difference.

A serious application should include a service capacity statement, not just a transport assessment. It should show how health, waste and community safety would be resourced during the construction phase, and how those resources would be withdrawn when the workforce leaves. Councils should be able to test those assumptions through the development consent order process and in their local impact reports.

Questions before the first spade

Residents and councillors do not need to oppose construction workers to demand a better sequence. They need to ask precise questions. Is the worker accommodation consented, funded and tied to the construction programme? What is the maximum occupancy, and who enforces it? What local lettings or nomination arrangements would apply? How would HMO licensing be resourced during peak demand? What transport would connect the campus to site, and what would prevent workers from driving into villages? What happens if the campus is delayed? What is the decommissioning plan? Who monitors the housing market effects, and what triggers a review?

These are not obstructive questions. They are the questions any responsible promoter should be able to answer. A pause is not a refusal to build. It is a demand that the beds arrive before the builders, and that the local housing market is not used as a temporary dormitory of last resort.

Heathrow Pause exists to protect local communities from being asked to absorb the costs of expansion while the benefits are counted elsewhere. On worker housing, the test is simple. If the campus is real, condition it. If it is not, say so. And if the plan is to let the private rented sector carry the load, residents deserve to know that before the first spade turns.