The two methods in 30 seconds
Both panellised SFS and stick-build SFS use the same cold-formed light gauge steel components — the same studs, the same tracks, the same gauges, the same fixing methods. The only difference is where the wall is assembled.
Stick-build SFS assembles individual studs and tracks one at a time on-site, in their final position. A crew sets out the bottom track, fixes studs at 600mm centres, fits the top track with deflection-head detail, and progressively builds up each wall section. Same process as timber stick-framing, but with steel.
Panellised SFS assembles the same studs and tracks in a factory or yard, into complete wall panels (typically up to 12m × 3m). Panels are delivered to site flat on a lorry, lifted into position by a tower crane or mobile crane, and connected to the primary structural frame and to adjacent panels.
Same material. Same end result. Very different site programmes, cost profiles and constraints.
Panellised: factory assembly, faster site programme
Panellised SFS production happens in a controlled environment — typically a large fabrication shed with overhead gantries, jig fixtures and standardised production stations. A typical UK SFS panel fabricator can produce 100-300m² of panel area per day per production line.
What goes into a panel varies by specification. A basic panel might include just the steel frame with sheathing applied. A fully-loaded panel can include sheathing, breather membrane, insulation, vapour control layer, internal plasterboard, window openings pre-formed, even pre-glazed windows fitted before delivery. The trade-off: more factory content means faster site closure but heavier panels (more crane capacity and transport effort), and more design lock-in before production.
On site, panellised SFS installs at approximately 200-400m² per day per crew and crane. A 6,000m² external envelope can typically be closed in 4-6 weeks with a single crew and crane working a single shift.
Stick-build: on-site assembly, design flexibility
Stick-build SFS doesn’t need factory production capacity — components are cut to length at the manufacturer (or sometimes at the SFS subcontractor’s depot) and delivered to site loose, ready to assemble. The install crew works from fabrication drawings, building each wall section in its final position.
Site assembly rate is typically 50-80m² per day per gang. A 6,000m² envelope takes 12-18 weeks with a single gang, or 6-9 weeks with two gangs working in parallel.
The slower rate is the cost. The benefit is flexibility: every wall is built in its final location, so design changes mid-construction can be accommodated without scrapping factory-built panels. Complex geometry — bay windows, oriels, recessed balconies, varied floor heights — is handled by adjustment on-site rather than redesign in the factory.
Programme comparison: 2,000m² panel vs stick (real BAS data)
From a 2024 BAS Frames project (large BTR scheme, 8 storeys, identical wall types across all upper floors):
- Stick-build option: 2,000m² of external SFS infill installed in 5 weeks with 2 gangs (target rate 200m² per gang per week)
- Panellised option (same project, modeled in parallel): 2,000m² installed in 2 weeks with 1 crew + 1 tower crane (target rate 1,000m² per week)
Net difference: 3 weeks saved on site programme using panellised. On the BTR scheme’s cost stack, those 3 weeks were worth approximately £165k in saved preliminaries plus £450k in pulled-forward rental income — total value approximately £615k.
Panellised material and supply cost on the same 2,000m² was £42k higher than stick-build (£21/m² premium). Net benefit of panellised: £615k – £42k = £573k saving on a single 2,000m² wall package.
These numbers don’t translate directly to other projects — every scheme has different prelims rates, financing costs, and labour markets — but the directionality holds. On programme-critical schemes, the per-m² premium of panellised is typically dwarfed by programme savings.
Cost comparison
Per-square-metre cost premium of panellised over stick-build, supplied and installed, UK 2026:
- Panellised basic (frame + sheathing only): £20-40/m² premium over equivalent stick-build
- Panellised mid-spec (frame + sheathing + insulation + plasterboard): £35-65/m² premium
- Panellised fully-loaded (frame + sheathing + insulation + plasterboard + pre-glazed windows + pre-applied breather membrane): £80-140/m² premium
The premium is real and unavoidable — factory production has overhead that on-site assembly doesn’t. Where panellised pays back is on programme, preliminaries, financing, and the value of earlier follow-on trade access. On schemes where those factors don’t outweigh the per-m² premium, stick-build is the right choice.
Site constraints that favour panellised
- Programme-critical: Where every week saved is worth more than the per-m² premium
- Repetitive design: Where the same panel design recurs many times across the building (factory benefits from repetition)
- Tower crane already on-site: Where the crane is being used for primary structure anyway, the marginal cost of using it for panel lifts is small
- Limited site labour availability: Where local skilled labour for stick-build is scarce or expensive
- Noise restrictions: Where local planning conditions limit on-site assembly hours; factory production is unaffected
- Site logistics constrained: Where limited site area or restricted storage favours just-in-time panel delivery
Design changes that favour stick-build
- Heritage retrofit: Where the building has irregular geometry and tight tolerances that don’t repeat
- Complex bay or oriel windows: Where each wall section is essentially bespoke
- Sites with no crane access: Tight urban sites, listed building courtyards, infill plots between existing structures
- Small project scale: Below approximately 1,500m² of SFS area, factory setup costs aren’t amortised
- Design still evolving: Where late client changes are likely and panel redesign costs would be prohibitive
- Mixed materials: Where SFS is interspersed with masonry, timber or other materials at scale-sensitive intervals
Hybrid approach: when to mix both methods
Increasingly common on UK projects since 2022: a single project uses panellised SFS for the bulk repetitive elements (typical apartment façades, hotel room walls, student bedroom modules) and stick-build SFS for the complex zones (ground-floor commercial frontage, building corners with bay windows, plant rooms with awkward service runs, top-floor penthouses with bespoke layouts).
The benefit: programme acceleration on the 70-80% of the building that is repetitive, design flexibility on the 20-30% that isn’t. The cost: more design coordination, more interfaces to manage, more decisions about where the panellised-to-stick transition lines fall.
On BAS Frames projects with hybrid SFS delivery in 2024-2026, the typical split has been 75-85% panellised by area, 15-25% stick-build. The transition zones are typically managed by the SFS subcontractor’s design coordinator working closely with the architect during RIBA Stage 4.
Quality and tolerance
Factory tolerance for panellised SFS: typically ±2mm on panel dimensions, ±1mm on stud spacing, ±0.5° on panel squareness. Achievable because of jig-based assembly, automated section cutting, and controlled environment.
On-site tolerance for stick-build SFS: typically ±10mm on wall dimensions, ±5mm on stud spacing, ±1° on wall squareness. Achievable because of variable site conditions, hand-cut sections, and weather-affected work.
These tolerances matter when follow-on trades need to interface with the SFS work. Window installers, cladding fixers, plasterboard finishers — all benefit from tighter SFS tolerances. The 8mm difference between panellised and stick-build tolerance often shows up as ~3-5% reduced rework in follow-on trades.
Decision checklist
Use this checklist when deciding between panellised and stick-build for your project:
- Is the SFS scope above 2,000m²? (Below this, stick-build is usually more cost-effective)
- Does the design have at least 70% repetition? (Below this, panellised loses much of its factory benefit)
- Is crane access available to all elevations? (No = stick-build)
- Is programme genuinely critical with significant late-delivery penalties? (Yes = panellised likely wins on cost stack)
- Is the design still evolving or could late changes be expected? (Yes = stick-build for flexibility)
- Is site labour for stick-build readily available and affordable in the local market? (No = panellised becomes more attractive)
- Are there noise or environmental restrictions on site assembly? (Yes = panellised reduces site activity)
If you’re answering yes to 4+ of these in favour of panellised, panellised is probably the right choice. If 4+ favour stick-build, stick-build is. If you’re mixed, hybrid is probably worth exploring.
Get a method recommendation from our engineers
For project-specific advice on whether panellised, stick-build or hybrid SFS suits your scheme, contact the BAS Frames team. We’ve delivered all three approaches across UK BTR, student accommodation, hotels and commercial projects. We’ll give you a method recommendation, an indicative cost comparison, and a programme estimate based on your specific drawings and constraints. For a worked case study, see our 2,000m² in six weeks project breakdown.
Frequently asked questions
The most common questions from main contractors and developers comparing panellised and stick-build SFS construction methods.
What’s the difference between panellised and stick-build SFS?
Stick-build SFS assembles individual steel sections on-site, piece by piece, to form walls in their final position. Panellised SFS assembles those same sections in a factory or yard into complete wall panels, then craned into position on-site. Same components, different point of assembly.
Which is faster — panellised or stick-build SFS?
Panellised SFS is typically 30-50% faster on-site because each panel installation takes minutes rather than hours of stud-by-stud assembly. However, the total programme (including factory production) is closer — panellised wins on programme-critical schemes; stick-build wins where site access prevents crane delivery.
When should I choose stick-build SFS over panellised?
Choose stick-build when: site access prevents craning large panels (tight urban sites, limited road access), the design has many unique conditions (heritage retrofits, complex geometry), the contractor has strong stick-build experience, or the project programme allows the slower on-site assembly.
Can panellised and stick-build SFS be mixed on one project?
Yes — and it’s increasingly common. Typical hybrid approach: panellised SFS for repetitive façade elements (BTR apartment walls, hotel rooms) and stick-build SFS for complex zones (ground-floor commercial frontage, plant rooms, geometry-rich features). Reduces overall programme without forcing a single-method compromise.
Is panellised SFS more expensive than stick-build?
Panellised SFS often carries a 5-15% per m² premium over stick-build because of factory overhead, transport and craneage costs. However, that premium is usually offset by shorter site programmes, reduced preliminaries, and faster envelope closure (allowing follow-on trades to start sooner). Net project cost is often lower.
