A defined reference system
WikiHouse Skylark is a structural building system. CNC routers cut engineered timber sheets into interlocking parts, which are assembled into blocks for walls, floors and roofs. The proposal uses Skylark 250 and the Switch House as its reference design and cost benchmark. Procurement remains open to other systems meeting the programme’s specification.
Source: WikiHouse product information.
What the proposal specifies
The reference Switch House is a two-storey, two-to-three-bedroom home of 92–104m². The proposal specifies 250mm wall insulation, a wall U-value of 0.14 W/m²K, triple glazing, roof-mounted solar panels, mechanical ventilation with heat recovery (MVHR), and an all-electric home. It substitutes an air-source heat pump for the template’s electric panel heaters and adds a drying cupboard.
These are design and procurement requirements. The wall U-value describes heat passing through the wall; it does not establish the whole home’s energy consumption. Junctions, glazing, airtightness, ventilation and occupant use also matter. An airtightness target needs a stated test method and pressure: the proposal’s air-changes figure must be resolved in the technical specification before it becomes a measurable acceptance criterion.
Screw piles are the reference foundation solution. Ground investigation and structural design must establish whether they suit the actual site. Cladding, roof details, drainage and service routes also need a complete project design.
Structure needs project-specific engineering
Published tests provide evidence about components and assemblies. WikiHouse’s research library includes beam, wall, joint, vibration and material testing. The project engineer must connect that evidence to the proposed design: loads, spans, connections, wind exposure, stability and foundation conditions.
A change of panel grade, thickness, block geometry or connection can change performance. The pilot therefore needs controlled drawing versions, material records, manufacturing checks and an inspection record linking the installed structure to the approved design.
Fire resistance belongs to a complete assembly
WikiHouse publishes fire-resistance ratings of up to REI 90 for walls and up to 60 minutes for floors and roofs with the specified plasterboard build-up. REI refers to loadbearing capacity, integrity and insulation during fire exposure. Its research library links the 2025 wall and floor test reports.
The applicable report, classification and permitted variations must support the exact proposed assembly. A rating cannot be transferred automatically to different linings, fixings, junctions or service penetrations. The timber chassis alone is not the tested finished wall.
The fire design must also address escape, detection, compartmentation where required, cavity barriers and external fire spread. Required resistance depends on the building and applicable guidance. The programme should not describe a test duration as a multiple of whole-home safety.
Source: WikiHouse published fire-performance claims.
Source: Approved Document B, including applicable amendments and transitional provisions.
The whole home must meet Building Regulations
Factory manufacture does not remove the need for building control. Beyond structure and fire, the design must address moisture, sound, ventilation, energy, overheating, sanitation, drainage, access and electrical safety. Approved Documents give guidance on meeting the requirements; the applicable edition and transitional arrangements must be established for the project.
A highly insulated, airtight home needs ventilation that is designed, installed, balanced and commissioned. Summer comfort must be assessed alongside winter performance. Moisture protection during delivery and erection, weatherproof details and access for maintenance belong in the delivery plan.
Competence, inspection and handover
Clients, designers and contractors have defined duties under the Building Regulations. Appointments must reflect the competence needed for the work. Assembly can offer an accessible entry route, with task-specific training and supervision; it does not remove those responsibilities. Construction-phase health and safety is also governed by CDM duties.
For the pilot, the acceptance record should include structural and fire evidence, material and installation checks, commissioning results, building-control completion documentation and resident instructions. The proposed ten-year warranty must be arranged on acceptable terms. Warranty cover and building-control compliance serve different purposes.
Sources checked 29 October 2026. Regulatory discussion applies to England.