Refurbishing a school science block: lab layouts, services and phasing

By Grayling Thomas Architects · November 2026

A school science block refurbishment succeeds or fails on the brief the science department writes before anyone draws a plan. The head of science should set out how many laboratories are needed and of what type, where the preparation room and chemical store sit, which services each room needs, and how the work will be phased around exam classes. The Department for Education's area guidelines give a general science laboratory 83 square metres for 30 pupils. Its current design standards, which form the employer's requirements for the DfE's own construction framework, give the extraction, fume cupboard and gas safety specification that a school project can use as its benchmark.

This guide is written for the head of science and the headteacher deciding together what to ask for. It draws on the DfE's Design standards: employer's requirements, published on 11 February 2026. Space figures come from Building Bulletin 103, the DfE's area guidelines for mainstream schools.

What should a school consider when refurbishing its science labs?

Start with why the work is happening. The reason shapes the design, the evidence and how the project is paid for.

A condition-led project begins with failing fabric or services: worn benching, corroded gas pipework, leaking waste runs, extraction that no longer clears the room. The case rests on evidence of condition, and the plan often stays broadly where it is. The technical manual lists laboratory furniture, including fume cupboards, at "20 years (with regular servicing and maintenance)", which is a useful yardstick when a department is still working with benching from a much earlier refit.

A curriculum-led project begins with teaching. There are too few labs for the timetable, rooms are too small for a full class to do practical work safely, or the prep room is on the wrong floor. Here the plan itself changes.

Most real projects are both. What matters is knowing which reason leads, because a condition case and a curriculum case are argued with different evidence, and only one of them is a repair.

Before the first design meeting, the department can usefully agree:

• how many labs the timetable needs, and which groups use each one;

• which rooms must take full-class practical work and which are mostly theory;

• which subjects need blackout, fume cupboards or specialist equipment;

• where technicians work and how materials move between rooms;

• which rooms can close in which terms.

Lab sizes: studio, general and specialist

The area guidelines describe three sizes of science room for secondary schools. A science studio is for "demonstration and light experiments", at 69 square metres for 30 pupils. A general science laboratory is 83 square metres for 30. A specialist science laboratory, for "demonstration for all types of experiments, up to A-level", is 90 square metres for 30.

To test whether the department is short of labs or short of the right size of lab, our guide to checking whether a school is short of space or short of the right rooms explains how to set the room schedule against the guidelines.

The bulletin suggests specialist labs "particularly where there are post-16 places", paired with studios that "would mainly be used for classwork, discussion and demonstrations". Many older labs are smaller than these figures, and that is often the real driver behind a curriculum-led project. The guidelines themselves "should always be applied flexibly in light of the particular circumstances", so an existing room slightly under size is a judgement for the brief rather than an automatic fail.

The DfE's pattern book says each laboratory "Can be directly linked to an adjacent laboratory or science classroom" and sits "Close to science preparation room". In a refurbishment, that adjacency is usually the hardest thing to recover, because labs were often added one at a time wherever space could be found.

Perimeter, island and peninsula layouts

Layout is where the head of science's experience counts most, and each common pattern trades something.

• Perimeter benching puts serviced benches round the walls, with loose tables in the middle for theory. Services are simple to route, but pupils have their backs to the teacher during practical work.

• Island layouts use serviced bollards or benches in the floor area, so groups face each other and the teacher can see every group. Services arrive through the floor or from above, which is harder in an existing building with a solid ground slab.

• Peninsula layouts run benches out from the side walls. They keep service runs short and give clear sightlines, at some cost to flexibility.

The DfE's test for any of them is functional. Furniture "shall allow pupils/students to carry out practical activities individually, in pairs and in small groups, be able to face the demonstration bench, and be observed by the teacher".

The technical manual also gives clearances. Tables placed back to back need 1400-1650mm between them, and a circulation route between tables side to side needs 900-1050mm. Behind a fume cupboard in use, the clearance to the wall is 1400mm. In an older, narrower room these distances decide whether island benching fits at all, more than the floor area does.

As a minimum, "one gas tap shall be shared between pairs of pupils/students, unless otherwise specified in the Project Brief". A department that wants more should say so in the brief.

Where should the prep room go?

The prep room is the part of a science block most often in the wrong place. The area guidelines ask for a "central preparation room for science laboratories totalling 0.35 to 0.5m2 for every workplace in science laboratories". It prefers one prep room, "ideally one for all science spaces but this may need to be more, for instance if science is over two floors".

The pattern book adds that "Preparation rooms include a fully separated science chemical store", and that prep rooms are "Directly linked to adjacent laboratories".

Two of the practice's projects show the choice in practice. The science block at Bourne Grammar School has "15 purpose-designed laboratories, each offering 90m² of teaching space, distributed across two floors". That is the two-floor case the guidelines anticipate, answered with "Dedicated preparation rooms equipped with dumb waiter systems", so technicians are not carrying trays of equipment up and down stairs.

On a smaller scale, at Bishop Stopford "A disused service yard within the site was reimagined as the location for two state-of-the-art science laboratories with adjoining prep rooms". Where a block has only a couple of labs, a prep room beside each one is often simpler than a central room down a corridor.

Gas, water and extraction

The figures below are the DfE's employer's requirements. On a project procured outside the DfE framework they are the benchmark to agree in the brief, alongside the Building Regulations and the school's own risk assessments.

This is where a refurbishment costs money, and where most of the DfE's requirements sit.

Extraction. Labs and studios need "a minimum exhaust ventilation rate of 4 l/s/m²", and prep rooms "a minimum exhaust ventilation rate of 7.5 l/s/m²". Chemical stores need "2ACH continuous ventilation i.e., 24 hours a day ventilation". Older labs served by a few wall fans rarely meet this, and extraction is often the item that turns a cosmetic refit into a services project.

Fume cupboards. "Fume cupboards shall be provided to 1 in 3 science laboratories and science studios, and in all science prep rooms", and they are of "the ducted type, unless otherwise specified in the Project Brief". They "shall be fixed in position in prep rooms and be able to be pulled out from the wall on flexible connections in science teaching spaces for demonstration purposes". At Bishop Stopford, "flexible mobile fume cupboards support a wide range of practical experiments".

Gas. Whether to connect to an existing natural gas supply or use an LPG system has to be evaluated, and the chosen solution agreed with the school. An emergency stop "shall be positioned near the teacher's desk/board with a second at the exit from the room". Each lab and prep room also needs "a lockable isolating valve to enable the gas supply to be shut off at the end of the day".

Water and drainage. The DfE standard specifies a Category 5 water supply system to serve "Outlets in science laboratories". Supplies to labs need "a means of isolation at the teaching wall". Sinks drain through "A polypropylene dilution trap" that "shall be fitted either before the stack or at each science sink".

Electrics. Labs and prep rooms need a local master shut-off that is "easily accessible by the teacher". There must also be "emergency electrical stop buttons positioned around the space local to any power supplies used for practical work".

None of this is optional detail for the contractor to sort out later. Each item changes where benches can go, where ducts run and which walls carry services, so it belongs in the brief from the start.

Storage, finishes and the chemical store

The area guidelines ask for a "separate store for chemicals off or near the preparation room". The technical manual treats "Storage space for fuel or other highly flammable substances e.g., chemical stores" as a place of special fire hazard, enclosed in "a minimum 30-minute fire-resistant construction (minimum REI 30)".

Whether the store needs a fixed bund is decided by "a suitable COSHH risk assessment", which determines "whether a fixed bund is required (preventing the use of trollies on castors)". Technicians who move stock on trolleys should be part of that conversation.

Lab floors are "Non-slip and chemical resistant lino, resin, rubber or vinyl", and polished concrete is ruled out in "areas with potential acid use (e.g., science laboratories)". For physics and biology, "One in three science laboratories shall provide blackout via blackout blinds for specific physics and biology experiments". The head of science should say which rooms those are, because blackout affects window design and ventilation.

Phasing around exam classes

A science department cannot simply close for a term. Phasing is the head of science's part of the programme, and it is best settled before the design is fixed rather than after the contractor is appointed.

Map which groups need which labs in each term, and protect practical time for GCSE and A-level groups first. Keep at least one fully serviced lab with a working fume cupboard open in every phase, and plan where technicians will prepare materials while their own room is out of use. Heavy services work, such as new extraction, gas pipework or drainage, is easier in the summer holiday. Room-by-room refits can run in term time if gas and water can be isolated to each room, which is one practical benefit of isolation at the teaching wall. Agree quiet periods around exams with the contractor, and keep noisy and dusty work away from exam rooms.

For the site-wide questions, such as contractor access, safeguarding and noise during exams, see our guide to building work on a live school site.

A new build can remove the phasing problem altogether. At Bourne, "The new science block freed up the school's existing laboratories for conversion into additional teaching spaces", and "Robust, low-maintenance materials were specified throughout to ensure swift construction delivery and minimize disruption to the school's daily operations".

Can CIF pay for a science block refurbishment?

It can, where condition leads the case. Bourne's block was "Funded through the Condition Improvement Fund (CIF)". At Bishop Stopford, "Funding for the scheme was successfully secured through a Condition Improvement Fund (CIF) bid".

The evidence for a condition-led science bid is mostly about services: gas installations, extraction, water, drainage and electrics. The practice's guide to CIF for heating, boilers and electrics sets out how a building services case is built for the current round. If the case is mainly about the curriculum, other routes may fit better; CIF, SCA and urgent capital support explains which applies to which school.

Related guides

• Your school is the client: CDM 2015 duties on a building project

• The CIF costed options appraisal: what every 2027 to 2028 bid must now include

• The CIF application for 2027 to 2028: a section-by-section walkthrough

Science block refurbishment at Grayling Thomas Architects

Grayling Thomas Architects is a RIBA Chartered Practice that designs and delivers school buildings, including science blocks funded through the Condition Improvement Fund. We work with heads of science and senior leaders from the first brief: surveying the existing labs and services, testing layouts against the DfE's clearances, planning the phasing around the school year, and preparing the condition evidence where a bid is the right route.

You can see more of our education and SEN architecture. To talk about your science block, contact Grayling Thomas Architects.