Summary
Greenhouse installation splits into the same pattern as most garden-building work: base construction (groundworks-priced), frame and glazing assembly (careful, methodical carpentry/glazing work — aluminium greenhouse kits are unforgiving of a base that's out of square), and optional services (guttering to a water butt, electrics for heating or propagation, water supply). The kit itself — aluminium, timber, or polycarbonate — is a client purchasing decision with a wide price range; this guide prices the installation labour and base around it.
This guide is for landscapers, handypersons, and general builders pricing greenhouse base construction and assembly for domestic clients. It covers base type selection, anchoring (critical — an unanchored greenhouse in an exposed garden is a genuine wind-damage risk), glazing considerations, and worked examples across small, medium, and large greenhouses. For general garden-building base pricing, see shed base pricing guide; for the permitted development and Building Regs framework that also governs greenhouses as outbuildings, see outbuildings regs.
The most common pricing mistake is quoting greenhouse installation as "just assembling a kit" without pricing the base to the exact footprint (aluminium greenhouse frames are unforgiving of an out-of-square base — a few millimetres out and panes won't seat correctly) and without pricing anchoring separately. A greenhouse blown over or racked out of square in its first winter storm is one of the most common callback complaints in this category.
Key Facts
- Frame materials — aluminium (lightest, cheapest, most common, needs secure anchoring due to low structure weight), timber (heavier, more traditional look, higher material cost, some self-weight stability), steel-framed commercial-style (rare domestic use, heaviest)
- Glazing options — horticultural glass (thin, 3mm, cheapest, brittle), toughened safety glass (BS EN 12150, recommended for lower panels and doors where impact risk is higher), polycarbonate twin/triple-wall (cheaper, better insulation, shatterproof, reduced light clarity vs glass)
- Base types — paving slab (standard for small aluminium greenhouses), concrete slab (standard for medium/large or heavier timber-framed units), brick/block dwarf wall (450–600mm high wall the greenhouse frame sits on — common on period-style and larger greenhouses, adds headroom for staging and borders below glazing level)
- Anchoring — aluminium greenhouses are light enough to be genuinely wind-vulnerable; anchor plates/brackets bolted through the base into the slab or dwarf wall are essential, not optional, in exposed sites
- Base sizing — build the base to the exact external footprint of the greenhouse base rail, level to within a few millimetres — unlike a shed, an out-of-square or unlevel base on a rigid aluminium frame causes glazing panels to crack or not seat
- GPDO 2015 Class E — greenhouses are treated as outbuildings under permitted development: single storey, eaves height capped at 2.5m throughout, overall height capped at 2.5m if sited within 2m of a boundary, total outbuilding coverage under 50% of curtilage — same regime as sheds and summer houses, see outbuildings regs
- Building Regs exemption — under 15m² floor area with no sleeping accommodation is exempt from Building Regulations, which covers the vast majority of domestic greenhouses
- Guttering — greenhouse guttering kits (usually manufacturer-specific for the frame system) route roof water to a water butt for irrigation reuse — a popular and inexpensive add-on
- Electrics for heating/propagation — SWA armoured cable run for a heater, propagator bench, or lighting is Part P notifiable work, same as any other outbuilding — see armoured cable
- Water supply — an outdoor tap or irrigation line run to the greenhouse needs frost-protected pipe burial (minimum 750mm in agricultural/garden ground) and is a plumbing-priced job, not included in basic installation
- VAT — Standard rate 20% applies; no reduced rate for greenhouses
Quick Reference Table
Spending too long on quotes? squote turns a 2-minute voice recording into a professional quote.
Try squote free →| Job Component | Small (6×8ft, ~4.5m²) | Medium (8×10ft, ~7.4m²) | Large (10×12ft+, ~11m²+) |
|---|---|---|---|
| Paving slab base | £320–£550 | £550–£850 | N/A (undersized) |
| Concrete slab base | £550–£850 | £850–£1,300 | £1,300–£2,200 |
| Brick/block dwarf wall base | N/A (rarely used) | £900–£1,500 | £1,600–£2,800 |
| Frame + glazing assembly | £180–£350 | £320–£550 | £550–£950 |
| Anchoring (base bolts/brackets) | £40–£80 | £60–£120 | £100–£180 |
| Guttering to water butt | £70–£130 | £100–£180 | £150–£260 |
| Electrics — heater/lighting circuit | £320–£480 | £380–£550 | £450–£650 |
| Typical installation total (excl. kit) | £400–£800 | £900–£1,800 | £2,200–£4,500+ |
Figures exclude VAT and the greenhouse kit purchase price, which varies significantly by frame material and glazing type.
Detailed Guidance
Building the price bottom-up
Price the job in four blocks:
- Base construction — sized precisely to the greenhouse footprint; see shed base pricing guide for detailed sub-base and slab cost buildup
- Frame and glazing assembly — methodical, careful work; aluminium kits go together fast if the base is dead level and square, slowly if it isn't
- Anchoring — non-negotiable in exposed sites, cheap insurance against wind damage
- Services (optional) — guttering, electrics, water supply
Worked example 1 — small aluminium greenhouse, 6ft × 8ft, paving slab base
Standard domestic greenhouse, sheltered garden position, no services required.
| Item | Cost |
|---|---|
| Site clearance and level, 1.5 hrs | £55 |
| Paving slab base, 100mm sub-base + 12 slabs | £420 |
| Frame and glazing assembly, 1 person, 4 hrs | £120 |
| Anchoring brackets and fixing | £45 |
| Cost subtotal | £640 |
| Margin (28%) | £179 |
| Quoted price (ex VAT) | £819 |
| Quoted price (inc VAT) | £983 |
Worked example 2 — medium polycarbonate greenhouse, 8ft × 10ft, concrete base, guttering
Family-size greenhouse, concrete slab base for durability and wind resistance, guttering to an existing water butt for irrigation.
| Item | Cost |
|---|---|
| Site clearance and level, 2 hrs | £70 |
| Excavation and formwork | £120 |
| Concrete slab base (100mm) | £780 |
| Frame and glazing/panel assembly, 2 people, 5 hrs | £300 |
| Anchoring brackets and fixing | £75 |
| Guttering kit and water butt connection | £140 |
| Cost subtotal | £1,485 |
| Margin (27%) | £401 |
| Quoted price (ex VAT) | £1,886 |
| Quoted price (inc VAT) | £2,263 |
Worked example 3 — large timber-framed greenhouse, 10ft × 14ft, dwarf wall base, heating circuit
Large timber-framed greenhouse on a brick dwarf wall base for a keen grower, with an electric heater circuit for frost protection and a propagation bench.
| Item | Cost |
|---|---|
| Site survey and setting out | £90 |
| Footings and brick/block dwarf wall (600mm high, damp course) | £1,850 |
| Frame and glazing assembly, 2 people, 1.5 days | £660 |
| Anchoring/fixing frame to wall plate | £140 |
| Guttering kit and downpipe to soakaway | £220 |
| SWA cable run (20m), trenching, ducting | £460 |
| Consumer unit circuit, heater point, lighting (electrician, sub'd) | £420 |
| Preservative treatment on wall plate/timber | £90 |
| Cost subtotal | £3,930 |
| Margin (25%) | £983 |
| Quoted price (ex VAT) | £4,913 |
| Quoted price (inc VAT) | £5,896 |
Base selection and why precision matters more than for a shed
Unlike timber sheds, which can tolerate a slightly uneven base because the frame is somewhat forgiving, rigid aluminium and timber greenhouse frames need the base level and square to within a few millimetres:
- Paving slab base — Fine for small aluminium greenhouses on already-flat ground. Check diagonals match (square check) before ordering the greenhouse kit dimensions.
- Concrete slab base — Better for medium/large greenhouses or any site needing levelling work — the pour itself corrects minor ground unevenness in a way slab laying can't.
- Brick/block dwarf wall base — Used on larger and premium (typically timber-framed) greenhouses. Raises the growing beds/staging above ground level, improves drainage and warmth retention, and gives a more substantial anchor point for the frame. Needs a proper footing and, ideally, a damp-proof course under the frame's timber sill if timber-framed.
Anchoring — the line item that prevents callbacks
Aluminium greenhouses are light structures — a 6×8ft aluminium frame can weigh under 40kg before glazing. In an exposed garden, wind uplift on a greenhouse roof is a genuine structural risk if the frame isn't mechanically fixed to its base:
- Use the manufacturer's anchor bracket kit, bolted through pre-formed holes in the base rail into the concrete or paving slab
- On paving slab bases, use resin or expanding anchor bolts rather than relying on the slab's own weight
- On exposed/coastal sites, budget for additional bracing or a heavier-gauge frame specification — flag this to the client at the quoting stage rather than after a storm
Glazing choice and where it affects price and safety
- Horticultural glass — cheapest, but brittle and prone to cracking from thermal stress or minor impact; increasingly avoided for lower panels near paths and doors
- Toughened safety glass (BS EN 12150) — recommended for base-level panels and door glazing where impact risk from tools, children, or pets is higher; costs more per pane but reduces injury risk and breakage callbacks — note that the exact regulatory trigger point for mandatory safety glazing in exempt garden buildings is not always clearcut, so treat this as strong good practice rather than a blanket legal requirement ****
- Polycarbonate — shatterproof, better insulation (useful for early propagation), but reduces light transmission clarity compared with glass — a genuine trade-off to discuss with the client rather than a straightforward downgrade
Frequently Asked Questions
Do I need planning permission for a greenhouse?
Almost never for a standard domestic greenhouse — it falls under GPDO Class E permitted development the same as a shed or summer house, provided it meets the height and boundary-proximity limits and doesn't push total outbuilding coverage over 50% of the garden. Listed buildings and Article 4 direction areas are the main exceptions — check before quoting.
How much extra should I charge for an exposed, windy site?
Add 20–40% to the anchoring line and consider recommending a heavier-gauge frame or a dwarf wall base instead of paving slabs for genuinely exposed sites (hilltop gardens, coastal locations, open aspect with no windbreak). This is cheap insurance compared with a wind-damage callback.
Can I lay the base before the client has actually bought the greenhouse kit?
Only if you have the exact external footprint dimensions from the manufacturer's spec sheet in advance — aluminium greenhouse bases need to match the frame's base rail dimensions precisely. Building a "roughly the right size" base and hoping the kit fits is a common and expensive mistake; always get the confirmed kit dimensions before pricing or pouring the base.
What margin should I target on greenhouse installation?
25–30% is typical, similar to summer house and shed base work. Larger jobs with dwarf wall construction and electrics carry more cost variability (sub-contracted electrician pricing, brick/block material cost swings) and should sit toward the lower end of that margin range to stay competitive.
Regulations & Standards
Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2, Part 1, Class E — permitted development rights for outbuildings including greenhouses
Building Regulations 2010 — exemption threshold for outbuildings under 15m² without sleeping accommodation
Building Regulations Part P — electrical safety notification requirement for any power supply to a greenhouse (heating, lighting, propagation equipment)
BS EN 12150 — toughened (tempered) safety glass standard, relevant to base panel and door glazing specification
BS 7671:2018+A4:2026 — Wiring Regulations, governing the electrical installation if power is supplied
shed base pricing guide — detailed base construction pricing this guide scales up for greenhouse footprints
outbuildings regs — full permitted development and Building Regs exemption conditions for garden structures, including greenhouses
armoured cable — SWA cable specification and burial depth for running power to a greenhouse heater or lighting
summer house installation pricing guide — comparable garden-building installation pricing model for summer houses