- Nordic spruce — £20–£40 per m² materials. Typical 3x3m garden room: £500–£1,000
- Siberian larch — £35–£70 per m² materials. Typical 3x3m garden room: £875–£1,750
- ThermoWood — £55–£95 per m² materials. Typical 3x3m garden room: £1,375–£2,375
- Charred timber — £75–£130 per m² materials. Typical 3x3m garden room: £1,875–£3,250
- Labour — £25–£45 per m² on top of materials if using a carpenter
- Battens and fixings — allow an additional £10–£15 per m²
Garden room cladding cost is one of the most searched questions among UK homeowners planning a garden office, garden studio, or outbuilding. The answer varies significantly depending on the size of the structure, the species of timber chosen, the profile, and whether you are supplying materials only or including labour. This guide gives you real 2026 figures for every scenario — from a basic 2x2m shed-style garden room in treated softwood to a fully specified contemporary garden office in charred timber — so you can budget accurately before requesting quotes.
All figures in this guide are based on current UK market pricing as of March 2026, drawn from our experience as a specialist timber cladding supplier delivering nationwide. For a precise quote based on your specific garden room dimensions and preferred species, contact our team and we will calculate the exact material quantity and cost.
How Much Cladding Does a Garden Room Need?
Before looking at costs per m², it helps to understand how much cladding area a typical UK garden room actually has. The total cladding area is the single biggest driver of overall cost.
| Garden Room Size | Approx Wall Area | Less Door/Windows | Net Cladding Area | With 15% Wastage |
|---|---|---|---|---|
| Small — 2x2m | ~16m² | ~4m² | ~12m² | ~14m² |
| Standard — 3x3m | ~24m² | ~5m² | ~19m² | ~22m² |
| Medium — 4x3m | ~28m² | ~6m² | ~22m² | ~25m² |
| Large — 5x4m | ~36m² | ~8m² | ~28m² | ~32m² |
| XL — 6x4m | ~40m² | ~10m² | ~30m² | ~35m² |
These are approximate figures assuming a single-pitch or flat roof with standard eaves height of 2.4–2.7m. Garden rooms with full-height glazing on one elevation will have significantly less cladding area. Always measure your specific structure and add 15% for cuts and wastage before ordering.
Garden Room Cladding Cost by Species — 2026 Prices
Vertical black cladding on a UK garden room — species choice is the biggest variable in cost, ranging from £20 to £130 per m² depending on the material and finish.
Total Material Cost by Garden Room Size
Combining cladding area figures with material costs per m² gives a clear picture of what the timber alone will cost for different garden room sizes and species:
| Garden Room Size | Nordic Spruce | Siberian Larch | ThermoWood | Charred Timber |
|---|---|---|---|---|
| Small — 2x2m (14m²) | £280–£560 | £490–£980 | £770–£1,330 | £1,050–£1,820 |
| Standard — 3x3m (22m²) | £440–£880 | £770–£1,540 | £1,210–£2,090 | £1,650–£2,860 |
| Medium — 4x3m (25m²) | £500–£1,000 | £875–£1,750 | £1,375–£2,375 | £1,875–£3,250 |
| Large — 5x4m (32m²) | £640–£1,280 | £1,120–£2,240 | £1,760–£3,040 | £2,400–£4,160 |
| XL — 6x4m (35m²) | £700–£1,400 | £1,225–£2,450 | £1,925–£3,325 | £2,625–£4,550 |
These figures cover cladding boards only. Add £10–£15 per m² for battens, fixings, and breather membrane. For a precise quote on your garden room contact our team with the dimensions.
Additional Costs — What Else Do You Need to Budget For?
Window reveal detail on a UK garden room — corner trims and reveal boards are often overlooked in initial budgets but are essential for a clean, professional finish.
| Additional Item | Typical Cost | Notes |
|---|---|---|
| Timber battens | £3–£6 per m² | Vertical counter-battens and horizontal fixing battens. Minimum 25mm cavity required behind cladding. |
| Stainless steel fixings | £2–£4 per m² | A4 stainless steel screws essential — standard steel fixings will rust and stain the cladding face. |
| Breather membrane | £2–£4 per m² | Required on most garden room installations behind the batten framework. |
| Corner trims / reveals | £15–£35 per linear metre | External corner posts and door/window reveal boards. Often overlooked — budget for these separately. |
| Exterior oil / finish | £80–£250 per garden room | If finishing on site rather than leaving to weather. Not required for ThermoWood or charred timber. |
| Installation labour | £25–£45 per m² | Experienced carpenter. Simple shiplap at lower end, shadow gap and rainscreen at higher end. |
The single most common cause of premature garden room cladding failure is using standard steel screws. On a sheltered garden room — particularly in a damp or shaded position — standard steel fixings can show rust staining within 2–3 years. Always specify A4 stainless steel fixings regardless of which species you choose. The cost difference is minimal, the performance difference is significant.
Total Installed Cost — Materials, Fixings & Labour Combined
Charred timber on a UK garden office — the highest upfront cost but the lowest whole-life cost, with virtually no maintenance required over 25–40 years.
| Specification | 3x3m garden room | 4x3m garden room | 5x4m garden room |
|---|---|---|---|
| Nordic spruce shiplap — budget | £800–£1,500 | £1,000–£1,900 | £1,300–£2,400 |
| Siberian larch shadow gap — mid | £1,400–£2,500 | £1,750–£3,100 | £2,200–£4,000 |
| ThermoWood triple shadow gap | £1,900–£3,200 | £2,400–£4,000 | £3,000–£5,100 |
| Charred timber — deep char or brushed | £2,400–£4,200 | £3,000–£5,200 | £3,800–£6,600 |
These all-in figures include cladding boards, battens, fixings, membrane, and labour. They exclude any finishing costs (oils, stains) which are optional and not required for ThermoWood or charred timber. All figures are based on UK national average labour rates — London and South East projects should add 20–30%.
Which Species Is the Best Value for a Garden Room?
The right choice depends on what you value most — upfront cost, long-term cost, appearance, or maintenance commitment. Here is an honest breakdown:
If budget is the priority
Nordic spruce shiplap is the cheapest upfront but requires re-treatment every 2–3 years. On a shaded or north-facing garden room this becomes costly and time-consuming over time. It is a reasonable choice for a temporary or short-term structure but not the best long-term investment for a permanent garden office.
If long-term value is the priority
Siberian larch shadow gap is the strongest mid-range choice — it costs £35–£70 per m², lasts 20–35 years with minimal maintenance, and looks excellent with a natural weathered or oiled finish. For most UK garden rooms this is the specification that delivers the best combination of cost, performance, and appearance.
If low maintenance is the priority
ThermoWood triple shadow gap is the best choice — no treatment required, 25–40 year lifespan, and the most popular contemporary profile for garden offices. The higher upfront cost is offset by zero ongoing maintenance cost over the life of the building.
If appearance and zero maintenance are both priorities
Charred timber is the answer — the deep black finish requires no treatment ever, ages gracefully without intervention, and creates the most visually striking garden office exterior available in any material. The highest upfront cost but the lowest whole-life cost of any option.
For a standard UK garden office where low maintenance and long lifespan are the priorities, ThermoWood triple shadow gap at £55–£95 per m² is the strongest all-round specification. For a garden room where appearance is the priority and budget allows, charred timber delivers the most striking result with the lowest ongoing commitment. For budget-conscious builds, Siberian larch is the sensible mid-ground — significantly better than softwood on durability, at a cost that remains accessible for most garden room budgets.
Garden room cladding materials typically cost £300–£3,500 depending on size and species. A typical 3x3m garden room costs £440–£880 in Nordic spruce, £770–£1,540 in Siberian larch, £1,210–£2,090 in ThermoWood, or £1,650–£2,860 in charred timber. Add £10–£15 per m² for battens and fixings, and £25–£45 per m² for installation labour.
Nordic spruce shiplap or feather edge is the cheapest option at £20–£40 per m². However it requires treatment every 2–3 years and may need replacing within 10–15 years. Siberian larch at £35–£70 per m² is a significantly better long-term investment — it lasts 20–35 years with minimal maintenance and costs only marginally more upfront.
A typical 3x3m garden room needs approximately 22m² of cladding including 15% wastage. A 4x3m needs approximately 25m². A 5x4m needs approximately 32m². Always measure your specific structure and add 15% for cuts and wastage. Contact our team with your dimensions for an exact quantity calculation.
Yes — DIY installation saves £25–£45 per m² in labour, typically £500–£1,125 on a standard garden room. Shiplap and feather edge are the most DIY-friendly profiles. Shadow gap and rainscreen require more precision. Always install over a ventilated batten framework with minimum 25mm cavity and use A4 stainless steel fixings throughout.
Nordic spruce lasts 10–15 years with regular treatment. Siberian larch lasts 20–35 years with minimal maintenance. ThermoWood lasts 25–40 years with very low maintenance. Charred timber lasts 25–40 years with virtually no maintenance. Correct installation — ventilated cavity, ground clearance, stainless fixings — makes as much difference to lifespan as species choice.
Get an Accurate Quote for Your Garden Room Cladding
Send us your garden room dimensions, preferred species, and profile and we will calculate the exact material quantity and cost. FSC and PEFC certified timber, nationwide delivery in 7–14 days. Supply only or supply and install available.