Building work on a live school site: phasing, safeguarding and keeping teaching going

By Grayling Thomas Architects · November 2026

Building work during term time is possible when the site is split in two. The contractor gets a fenced, separately accessed compound; the school keeps safe, unbroken routes for pupils; and the noisiest, most disruptive tasks move into holidays, weekends or agreed quiet windows. The head's job is to decide early what must happen in the summer, what can run in term, and where classes go meanwhile. Then the contractor's construction phase plan has to show, in writing, how those decisions will be kept.

This article is written for the headteacher or deputy who will be running the school while the work happens. It covers the operational decisions, not the funding or the design.

Should building work happen in the summer holidays or during term time?

Most heads would put everything into the summer if they could. An empty site removes the hardest problems at once: no pupils crossing the site, no noise in lessons, no safeguarding questions about contractors near children. For small works that fit inside the holiday, this is usually the right answer. Grayling Thomas Architects plans single classrooms, toilet blocks, secure lobbies and similar small works and modular buildings around the calendar for exactly this reason, "planning and scheduling these projects during school holiday periods" so that teaching is not interrupted.

The summer stops being enough once the work is larger. A new teaching block, a hall or a substantial extension will take longer than one holiday, and trying to squeeze it in tends to cause the outcome every head fears: a building that is not ready in September, with no plan for where the classes go.

A better question than "summer or term?" is which tasks belong in which period. As a rule of thumb:

• Holiday tasks: anything inside occupied buildings, work to services that teaching relies on (heating, power, water, fire alarm), connections between old and new buildings, demolition near occupied rooms, and the final move into new spaces.

• Term-time tasks: work inside a fully separated compound, such as foundations, frame, roof and envelope, and fit-out of a building pupils do not yet use.

• Weekend or after-hours tasks: large deliveries, crane lifts, noisy cutting and anything that briefly needs the shared entrance.

When the timetable is set this way, the term-time part of the job becomes a question of separation rather than tolerance.

Phasing a project around a working school

Phasing is how a large project stays compatible with a school that never closes. Each phase hands back something usable before the next one starts.

The clearest example from the practice's own work is All Saints Primary School. The challenge was "to design a building occupying as little ground area as possible, enabling the existing junior school to operate fully during the new build, only two meters away". The construction was split into three phases: "Enabling works and MUGA; School hall as two temporary classrooms; New 420-place primary school." The second phase delivered the school hall, used as two temporary classrooms while the main building went up. "The existing school was eventually demolished to complete the landscaping."

What this shows a head is that phasing is decided at design stage, not by the contractor once on site. The order in which spaces are built, and which of them can serve as temporary accommodation, has to be designed in from the start.

Separating the site from the school

The single most useful thing a head can insist on is a physical line between the construction site and the school, held for the whole job.

Things to agree on a site plan before work starts:

• The compound boundary. A full-height fence, not tape or barriers, around everything the contractor controls, including storage and welfare cabins.

• A separate contractor entrance. If the site has only one gate, decide who uses it when, and put a banksman on every vehicle movement.

• Delivery windows. Keep lorries out of the drop-off and pick-up periods, playtimes and lunch. Write the times into the contract.

• Pupil routes. Mark how classes reach the hall, dining room, playground and toilets when part of the site is closed. Walk them with the staff who use them.

• Fire escape routes. Check that every evacuation route and assembly point still works with the compound in place.

• The handover line. Agree how and when any area passes from the contractor back to the school.

The DfE's health and safety advice for schools says they "should also have procedures for controlling access and barring individuals from school premises." A construction project creates a second set of people with access to the site, and the plan should make clear how the two sets are kept apart.

Safeguarding and contractors on the school site

Contractors who stay inside a separated compound rarely meet pupils. The safeguarding risk is concentrated in the places where the two worlds overlap: work inside the school, shared entrances, toilets and the end of the day when gates open.

Decide, in line with your own safeguarding policy, what checks you need for anyone who will work where pupils are, and put that requirement in the contract before the contractor prices the job. Then agree the practical rules with the site manager:

• how operatives sign in and are identified (badges, hi-vis colours, a register held by the school office);

• that nobody works unsupervised in occupied areas, and who escorts them;

• that contractors use their own welfare facilities, not pupil toilets;

• the rules on phones, photography and smoking at the boundary fence;

• who the site manager calls if a pupil is found on the wrong side of the line.

The DfE's health and safety advice lists contractors alongside staff, pupils and visitors among the people whose health and safety a school's risk assessments must consider. Update yours when the work starts, and again at each change of phase. The same guidance says to review the assessment if "there has been a significant change in related matters", and a building site arriving next to classrooms is one.

Exams, noise and the school calendar

Give the contractor your calendar for the whole contract period before they programme the job: exam weeks, mock exams, assessment weeks, open evenings, performances and sports days. Ask for a programme that shows how noisy work avoids them, and for a named quiet-working rule (for example, no breaking or cutting during timed papers) that the site manager can enforce without referring back.

For a science block, where exam groups need working labs in every phase, our guide to refurbishing a school science block covers how to plan the phases.

Noise also depends on what is next to what. A hall used for exams should not sit beside the compound if another room can be used. For pupils with SEN, sudden noise, vibration and changes of route can matter more than they do for others; plan visual timetables, social stories and quiet spaces with the SENCO before the hoarding goes up.

Decant classrooms and temporary accommodation

Where a class has to move out of its room, there are three usual options: a temporary modular classroom, a room elsewhere on site (often the hall or library), or a finished part of the project used early, as at All Saints. The choice depends on cost, how long the move lasts, and how much of the school's daily routine it disrupts.

Temporary classrooms need their own planning: a base, power, data, a safe covered route, and somewhere outside the construction compound. The practice's article on CIF funding for modular and temporary classrooms sets out what a Condition Improvement Fund bid can and cannot cover for decant space.

Tight timescales are workable when the end date is fixed and everyone plans to it. At Mendlesham SEN, the practice worked on the conversion of a community hall into "2 SEN Specialist Classrooms, Group Rooms, Offices and Toilets". The project "was limited to a tight timeframe to enable students to move in to the building at the start of term", and "was constructed in 16 weeks." The start of term was the date that mattered, and the programme was built backwards from it.

How do schools keep teaching safely while building work happens on site?

They treat the project as a change to how the school runs, not just a building job. In practice that means a separated site, a phasing plan agreed at design stage, updated risk assessments, clear safeguarding rules for contractors, and a programme that respects the school calendar. Responsibility is shared but not blurred. The DfE's advice says "The employer or, in the case of independent schools, the proprietor, is accountable for the health and safety of school staff and pupils", while the day-to-day running "is usually delegated to the headteacher and the school management team."

The legal framework for the building work itself is the Construction (Design and Management) Regulations 2015. The organisation commissioning the work is the client, and HSE guidance says commercial clients must "ensure that the principal contractor or contractor (for single contractor projects) prepares a construction phase plan before that phase begins". Larger jobs are notifiable to HSE where work "will last longer than 30 working days and involves more than 20 workers at any one time; or where the work exceeds 500 individual worker days". The HSE's guidance for commercial clients sets out the full list of client duties.

Our guide to a school's CDM 2015 duties as client explains each duty in turn, from pre-construction information to the health and safety file.

What should a construction phase plan cover for a school?

The construction phase plan is the contractor's document, but it is the head's best tool for holding the job to account. Ask to see a draft before work starts and check that it covers, specifically for your site:

• the compound boundary and how it changes at each phase;

• vehicle routes, delivery times and banksman arrangements;

• pupil and staff routes, including fire escape routes and assembly points;

• the sign-in, identification and supervision rules for operatives;

• the working hours, quiet periods and the exam and events calendar;

• work inside occupied buildings and how those areas will be closed off;

• how dust, noise and services shutdowns will be managed and notified;

• a named site manager and a named school contact, with a weekly meeting.

If the plan reads like a generic template, send it back. A plan that does not mention the school's own routes and timetable will not protect them.

Keeping parents informed

Parents notice building work before anything else: the fence, the lorries, the changed drop-off. Tell them before the compound goes up, with a simple site plan, the new walking routes and the delivery times. Repeat the message at each phase change, and say clearly what will be different for their child, such as a class moving rooms. A short update in the newsletter, with a photograph of progress, does more for goodwill than a long letter at the start.

Related guides

• What governors should check before approving a school building project

• Boarding house design: what an independent school should put in the brief

• Oxfordshire's new SEND resource bases: what a host school needs from the building

Building work on live school sites at Grayling Thomas Architects

Grayling Thomas Architects is a RIBA Chartered Practice that designs and delivers school buildings. We plan phasing, site separation and temporary accommodation into the design, so that the school can keep running while the work happens, and we take projects from first brief to completion on site through our design and construction service. Our wider education and SEN architecture work covers new buildings, extensions and refurbishments for schools.

If your school is planning work and you want to talk through how to keep teaching going, contact Grayling Thomas Architects.