Timber Frame Construction Costs UK — What to Charge for Self-Build and Extension Timber Frame in 2026
Timber frame is the fastest-growing construction method in the UK — it now accounts for around 25% of new homes built annually, and that share is rising. If you erect timber frame structures, manufacture kit, or manage self-build projects, you need accurate current pricing to quote competitively and protect your margin. This guide covers all four main timber frame system types, supply-only kit costs, erection labour, complete shell costs for typical projects, what drives prices up and down, and how to quote erection work professionally. It also covers the structural, building regulations, and fire compliance questions your clients will ask.
Timber frame system types and supply-only kit costs (2026)
“Timber frame” covers four distinct systems with meaningfully different costs, site programmes, and thermal performance. The supply-only kit price is what you pay to the manufacturer for the structural frame delivered to site. It does not include foundations, cladding, roof covering, windows and doors, or internal fit-out. All figures below are per square metre of gross floor area (GFA).
| System type | Supply only (per m² GFA) |
|---|---|
| Open panel | £600 – £1,000 |
| Closed panel | £800 – £1,400 |
| SIP (Structural Insulated Panels) | £900 – £1,600 |
| Volumetric / modular (all-in) | £1,500 – £2,500 |
UK average 2026. Prices exclude VAT. Supply-only figures cover kit manufacture and delivery to site. Foundation, roof covering, cladding, windows, doors, and fit-out are additional costs.
The four system types explained
Open panel timber frame
The most basic factory-manufactured system. Panels consist of a structural timber stud frame with OSB sheathing on one face. Insulation is not factory-fitted — it is installed on site between and/or over the studs by the erection crew or a follow-on insulation contractor. Breather membranes and service chasers are also applied on site. The upside is the lower kit cost and flexibility to specify insulation types and depths on site. The downside is that achieving the higher Part L airtightness targets requires careful on-site detailing, which is heavily dependent on the skill of the erection crew.
Best suited to: budget-conscious self-build projects, developers comfortable with site-applied insulation, and extensions where the client wants to manage costs tightly.
Closed panel timber frame
Closed panel systems arrive on site with insulation already factory-fitted within the stud cavity, breather membrane applied to the external face, and often a vapour control layer and service batten on the internal face. Some closed panel systems also include pre-fitted windows and doors, utility chases, and even electrical conduit runs. Erection is significantly faster than open panel because the panels are essentially finished structural elements — a competent erection crew can have a 100m² house shell weathertight within 2–4 days.
The higher kit cost compared to open panel is largely offset by the reduced on-site labour, faster programme, and more consistent thermal performance. For self-build clients on a tight programme (perhaps borrowing on a bridging loan), the faster erection timeline has real financial value.
SIP (Structural Insulated Panels)
SIPs are a completely different structural approach — rather than a stud frame, the structural element is a rigid composite panel consisting of two OSB skins bonded to a polyurethane (PUR) or expanded polystyrene (EPS) insulation core. The panel carries structural load in both compression and bending, meaning the insulation itself forms part of the structure. This results in exceptionally high airtightness and very low U-values with minimal wall thickness.
SIP buildings routinely achieve airtightness results of 1–3m³/h/m² at 50Pa and can be designed to full Passivhaus standard (≤0.6m³/h/m²) with careful detailing at panel junctions and openings. The higher kit cost reflects the manufacturing precision and the performance delivered. Lead times are typically 8–14 weeks from order confirmation.
Volumetric / modular construction
Volumetric construction takes factory completion to its logical conclusion. Complete room modules — fully fitted out with internal finishes, electrics, plumbing, kitchen and bathroom units in some cases — are manufactured in a factory, transported to site, and craned into position. Site time is measured in days rather than weeks. The all-in price range of £1,500–£2,500/m² reflects a fundamentally different cost model: most of the construction budget is spent at the factory rather than on site.
Volumetric is most cost-effective at scale (multiple identical units), on constrained urban sites where site programme is expensive, and on complex projects such as hotels, student accommodation, or multi-storey residential. For a single self-build house, volumetric is rarely the most economical choice, though it can still be appropriate where programme speed is the priority.
What a “supply only” kit price includes — and what it doesn't
This is one of the most common points of confusion in timber frame pricing, particularly for self-build clients who are comparing quotes from different manufacturers. Be specific in your client communications.
A standard supply-only kit price includes:
- Engineered timber stud frame panels (factory-cut and pre-assembled)
- OSB structural sheathing board
- Breather membrane (typically taped and lapped at factory for closed panel)
- Sole plates (treated timber to sit on the foundation slab)
- Structural fixings (joist hangers, brackets, strap ties, nails)
- Erection drawings and structural calculations reference pack
- Delivery to site (usually one or two loads on a flatbed)
A supply-only kit price does not include:
- Foundation and slab (concrete strip, raft, or pad — separate groundworks cost)
- Erection labour and crane hire
- Roof structure (open or closed panel kits typically stop at wall plate level)
- Roof covering (tiles, slates, or flat roof membrane)
- External cladding (brick skin, render, timber, or composite)
- Windows and external doors
- Internal fit-out (first and second fix electrics, plumbing, plastering, flooring, decoration)
When quoting for a self-build client who has received a kit price from a manufacturer, make sure they understand the delta between “kit supplied” and “house finished and ready to occupy.” The kit is typically 20–35% of the total project cost. Everything else — groundworks, erection, roof, cladding, fit-out, M&E, landscaping, and professional fees — makes up the remainder.
Erection labour: what to charge and what to allow
Timber frame erection is specialist work. A structural erection crew typically consists of three to five experienced carpenters led by a frame erector who has specific training in lifting, sequencing, and temporary propping. Crane hire is required for all but the simplest single-storey extensions.
| Cost item | Typical cost |
|---|---|
| Erection labour (per m² floor area) | £50 – £100 |
| Crane hire (day rate, 12–16 tonne, with operator) | £800 – £1,400 per day |
| Crane hire (half-day minimum, smaller telescopic) | £500 – £800 |
| Temporary propping and bracing materials | Typically included in erection rate |
| Erection programme, 100m² house | 2–5 days (closed panel faster) |
| Erection programme, 50m² extension | 1–2 days |
UK average 2026. Crane requirements depend on site access, panel sizes, and panel weight. Always assess crane access before quoting.
Erection labour rates vary significantly based on panel system, site conditions, and the complexity of the design. A simple rectangular single-storey extension erects faster per square metre than an L-shaped two-storey house with multiple gable features. Always attend site before quoting erection — the variables that move the price are only visible on the ground.
Typical shell costs for common project types
The figures below are for the timber frame shell only — kit supply, erection labour, and crane hire. They do not include foundations, roof covering, cladding, windows and doors, or any internal fit-out. These are useful as a benchmark when your client asks “what will the frame cost me to get up?”
100m² 3-bed house, closed panel
£80,000 – £140,000Kit supply £80,000–£140,000 includes erection and crane. Kit alone typically £80,000–£112,000 at closed panel rates; erection adds £5,000–£10,000.
50m² single-storey extension, open panel
£35,000 – £60,000Kit supply at open panel rates plus one-day crane and 1–2 day erection crew. Simpler geometry keeps erection time short.
200m² 4-bed detached, SIP
£180,000 – £320,000SIP kit at premium end of range. Faster erection partially offsets the higher kit cost vs closed panel. Airtightness performance is significantly better.
To budget a complete finished house from these shell costs, multiply by 2.5–4 depending on specification. A basic self-build finish adds less; a high-specification contemporary finish adds significantly more. Ground conditions, site access, and M&E specification are the biggest variables.
What drives timber frame costs up or down
- →Storey height. Standard storey height (2.4–2.7m) is the base rate. Non-standard storey heights — vaulted ceilings, double-height glazing features, or taller-than-standard floor-to-ceiling heights — increase panel sizes, crane requirements, and erection complexity. Specify storey heights clearly when requesting kit prices.
- →Floor plate complexity. A simple rectangle is the cheapest floor plate to manufacture and erect. An L-shape, T-shape, or complex footprint with internal corners and re-entrant angles adds significantly to panel count, junction detailing, and erection time. Complexity also affects crane positioning — an irregular footprint may require crane repositioning mid-erection, adding time and cost.
- →Window and door opening count and size. Large openings weaken the structural panel and require additional engineered timber lintels or steel within the panel frame. Bi-fold doors, large glazed gables, and floor-to-ceiling windows add both material cost and structural complexity. Each large opening needs to be specifically engineered and priced.
- →Structural engineer specification. The structural engineer determines stud centres, stud depth, header sizes, and any requirement for steel within the frame. A more complex architectural design produces a more complex — and more expensive — engineer's specification. Never finalise a kit price with a manufacturer without having at least a preliminary structural engineer's scheme to reference.
- →Crane access. Sites with excellent road access and a clear hardstanding for the crane are the easiest and cheapest to erect. Restricted urban sites, sites with overhead cables, and sites where the crane must reach over a neighbouring property significantly increase crane hire cost and erection time. Always check for overhead electricity cables before booking the crane — this is a safety-critical site survey task.
- →Distance from road. Kit is delivered on a flatbed. If panels need to be carried or slid a significant distance from the delivery point to the crane position, this adds handling time. On very tight sites, panels may need to be craned directly off the delivery vehicle — which requires careful programme coordination and may incur a standby charge if the crane is waiting for the delivery vehicle.
Structural engineer: always required for timber frame
Timber frame construction is not self-certifying. A structural engineer is required on every timber frame project to produce calculations and drawings that comply with Eurocode 5 (BS EN 1995, the design standard for timber structures) and BS 5268 (the permissible stress design code for structural timber). These are required by the building control authority before a Building Regulations application can be approved.
Structural engineer fees for a timber frame house run to £1,500–£4,000 depending on design complexity, number of storeys, and whether steel elements are incorporated within the frame. For a single-storey extension, expect £800–£1,800. Some timber frame kit manufacturers include a basic structural calculation package within the kit supply price — check whether this is a full BS EN 1995 compliant package or a manufacturer's standard detail reference, which is not the same thing.
Budget for the structural engineer at the start of the project programme, not after the kit has been ordered. Their output — particularly panel specifications and connection details — must be incorporated into the manufacturer's drawings before the kit goes into production.
Building regulations: what timber frame must comply with
Timber frame is a fully compliant construction method for all building types when designed correctly. There are no blanket restrictions on using timber frame — the compliance question is always one of design detail, not system type.
Part A – Structure
The structural frame must be designed to Eurocode 5 (BS EN 1995-1-1) for new designs, with calculations submitted to building control. The calculations cover dead loads, imposed loads, wind loads, and connection design. Compliance with Part A is demonstrated through the structural engineer's calculations and the manufacturer's CE-marked components where applicable.
Part B – Fire safety
Timber frame houses are safe when designed to Part B. The external wall construction must achieve a minimum 30-minute fire resistance (REI 30) from both internal and external faces for most domestic applications. Cavities within the external wall must be fire-stopped with intumescent cavity barriers at maximum 8m intervals horizontally and vertically, and at all junctions with floors, ceilings, and party walls. For buildings over 11m in height, additional requirements apply including the prohibition on combustible cladding materials.
Automatic sprinkler systems are required in all new residential buildings in Wales (since 2016) and are increasingly specified in England, particularly for buildings above certain heights or in certain occupancy types. Budget £2,500–£6,000 for a domestic sprinkler system if required.
Part E – Sound (separating walls)
For terraced or semi-detached timber frame houses, Part E requires separating wall performance equivalent to masonry. This is achieved through a twin-stud or I-joist separating wall with an acoustic quilt and staggered plasterboard linings. Pre-completion testing (sound testing) is typically required. If you are quoting a party wall construction, the acoustic specification adds cost and erection time compared to a standalone house.
Part L – Airtightness and thermal performance
Timber frame excels at Part L compliance. The standard airtightness target for new dwellings is ≤5m³/h/m² at 50Pa. Higher-specification clients target ≤3m³/h/m² (broadly equivalent to the former Level 4 of the Code for Sustainable Homes), and Passivhaus projects target ≤0.6m³/h/m². Closed panel and SIP systems routinely achieve 1–2m³/h/m² with standard junction detailing — open panel can achieve the same but requires more careful site-applied membrane lapping and taping. An air pressure test is required on completion.
Lead times: plan your programme around the kit manufacturer
Timber frame kit manufacture takes 6–16 weeks from order confirmation to delivery, depending on the manufacturer's current workload and the complexity of the design. SIP panel systems and bespoke closed panel systems typically sit at the longer end of this range.
For self-build clients, the kit lead time is the single most common cause of programme delay. The typical mistake is to place the order only after planning permission has been granted — by which point a 14-week lead time pushes erection into winter or beyond the client's target occupation date. The correct approach is to engage the manufacturer during the planning application stage, agree a provisional slot, and confirm the order (with deposit) as soon as planning is granted.
Crane hire should be booked as soon as the kit delivery date is confirmed. In busy periods, crane availability in rural areas can be limited — particularly for specialist telescopic cranes needed on restricted sites.
Timber frame vs traditional blockwork: the practical comparison
Self-build clients will ask you this question directly. Here are the honest trade-offs to present:
| Factor | Timber frame | Traditional blockwork |
|---|---|---|
| Speed to weathertight shell | Days (2–5 for a house) | Weeks (6–12 for a house) |
| Thermal performance | Excellent — Passivhaus achievable | Good — harder to achieve very low U-values |
| Airtightness | Excellent — easily ≤3m³/h/m² | Moderate — requires careful detailing |
| Load on foundations | Lighter — can reduce foundation spec | Heavier — standard strip or raft required |
| Design flexibility | High — long spans, complex geometry | Moderate — limited by masonry constraints |
| Kit lead time | 6–16 weeks required | No pre-order required |
| Trade familiarity | Specialist erection crew required | Any competent bricklayer/blocklayer |
| Cost | Comparable — kit offsets site labour | Comparable — labour-intensive but no lead time |
The overall cost of a completed timber frame house and a completed blockwork house of the same design are broadly comparable in 2026. The differences are in the programme, the thermal performance achieved, and the trade skills required. Timber frame is not inherently more expensive — the kit cost substitutes for the extended blockwork labour programme.
How to quote timber frame erection professionally
Timber frame erection is one of the easiest types of work to underquote because the variables — site access, panel sequence complexity, crane reach required — are invisible from a drawing. Follow this approach to protect your margin.
1. Always attend site before quoting
Walk the site and assess: road access width (can the delivery flatbed get in?), overhead cables (are they a crane obstruction?), hardstanding area for the crane (is there a firm, level area large enough?), distance from crane position to furthest panel lift, and whether the crane will need to lift over any existing structure. These factors determine whether you need a small telescopic crane or a larger vehicle-mounted crane, and how many crane repositions will be needed.
2. Quote erection separately from kit supply
Even if the client has asked for an all-in price, produce your erection quote as a separate document internally. This lets you see the margin on each element clearly and present a breakdown to the client if challenged on the total. The erection quotation should cover: structural erection crew (number of operatives, day rate, number of days), crane hire (day rate times estimated days, with crane operator included), temporary propping and bracing materials, and any prelim costs specific to the erection programme (compound, welfare, PPE).
3. Include a clear programme and access requirement
Your erection quotation should state clearly what site conditions you are quoting on: foundation ready and level, sole plates positioned and chemically anchored, safe access for delivery vehicle, clear crane hardstanding. If these conditions are not met on the erection start date, the programme will slip and you will incur additional crane standby costs. State this in writing. The client's groundworks contractor is responsible for having the slab ready — make sure this is explicitly confirmed before you commit the crane.
4. Confirm the manufacturer's erection manual is available
Every reputable timber frame manufacturer produces an erection manual specific to the project. This document contains the panel sequence, connection details, temporary bracing requirements, and lifting points. Do not start erection without it. If you are erecting a kit from a manufacturer you have not worked with before, request the manual and review it before your site visit — not on the morning of erection.
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