Wooden vs aluminium greenhouses

The choice is about ownership, not just looks

Frame material affects how a greenhouse looks on day one, but the more useful comparison is how it behaves over years. Timber asks for closer attention to moisture and finishes. Aluminium asks for careful assembly, compatible fixings and reliable anchoring. Both need cleaning, moving-part checks and a level foundation.

Start by deciding whether the greenhouse is primarily a working structure, a prominent garden feature or both. Then compare specific models. A premium installed timber glasshouse and a lightweight aluminium polycarbonate kit do not represent every greenhouse made from those materials.

Maintenance

Aluminium normally needs the lighter care schedule. Wash away algae and dirt, clear channels and gutters, lubricate moving parts as instructed and inspect anchors and fasteners. Painted or powder-coated frames should be checked for damage, especially near the base.

Timber care depends on treatment. Some pressure-treated structures require no routine preservative during the guarantee period; others ask for annual retreatment. Lower rails, cut ends and door bottoms deserve attention because they experience splashback and prolonged damp. Never assume that a long anti-rot guarantee means site drainage is irrelevant.

If you enjoy maintaining timber garden buildings, the schedule may be a pleasure rather than a burden. If you already struggle to clean the glazing, aluminium is the more realistic choice.

Light and internal shadow

Slim aluminium glazing bars leave more of each wall and roof as glazing. That is valuable in winter and in compact houses where every shadow covers a larger share of the growing area. Timber bars are broader, though their shade moves across the day and does not make a well-sited greenhouse unusable.

Glazing has a larger effect than frame colour. Clear toughened glass, horticultural glass and twin-wall polycarbonate transmit and scatter light differently. Compare the full frame-and-glazing package rather than treating material decisions separately.

Strength and exposure

Wood feels substantial; aluminium feels light. Neither impression proves how the assembled greenhouse will handle wind. Strength comes from profile design, joints, bracing, panel retention, geometry and the connection to the foundation.

On an exposed site, a rigid base and anchors are essential. Keep the structure out of severe wind funnels and away from falling branches, while avoiding deep shade. Doors and vents should close positively. If the manufacturer limits suitable wind or snow exposure, take that seriously.

Installation and adjustment

Aluminium kits typically contain many small sections, clips and bolts. Assembly rewards methodical sorting and a perfectly square base. Do not fully tighten everything before the instructions call for it; the frame may need adjustment as glazing and doors are aligned.

Timber structures use larger, heavier components. Frames may be supplied in panels or installed professionally, but the base still has to meet the maker's tolerances. Timber can be worked and repaired with familiar tools, yet careless site cutting may expose untreated wood or invalidate a guarantee.

Delivery access can decide the material. Long aluminium packs may pass through a narrow route, while pre-assembled timber panels and large glass panes may not. Check package information before ordering.

Accessories and internal layout

Timber offers intuitive fixing points, provided the manufacturer permits them and the loaded accessory will not weaken the frame. Aluminium uses proprietary clips, channels and bolts, which preserve the frame but require compatible parts.

Do not let accessory convenience distract from basic working space. Door width, threshold, eaves height, vents and staging depth determine daily usefulness. A compact timber walkaround with doors on several sides can be more accessible than a nominally larger aluminium greenhouse with a narrow central opening.

Appearance and planning context

Timber often suits older buildings, conservation-minded settings and gardens where the greenhouse is visible from the house. Aluminium can recede visually, particularly with a dark green finish and planting around the base. Silver frames reflect more light and have a clean utilitarian appearance.

Appearance can matter to a planning authority in sensitive locations, but choosing timber does not automatically remove the need for permission. Check the rules for your nation, property and site using our UK greenhouse planning permission guide.

Cost over the life of the greenhouse

Compare more than the purchase price. Include the base, anchors, glazing option, vents, staging, delivery access, installation, replacement parts and maintenance coatings. A professionally installed wooden greenhouse may cost substantially more at the start but include staging and labour. An aluminium kit may be cheaper but require a base, extra vents and self-assembly time.

There is no honest universal payback calculation because exposure, maintenance and product quality vary. The sound choice is the frame you can install correctly and care for consistently.

Which should you buy?

Choose aluminium if low frame upkeep, slim glazing bars, broad availability and kit-format delivery are priorities. It is the dependable default for many ordinary gardens.

Choose wood if the material is important to the garden, you want substantial joinery or easy compatible fixing points, and the care schedule fits your habits. Treat it as a long-term garden building rather than a decorative impulse purchase.

Whichever you choose, verify the exact footprint and prepare the right greenhouse base. A modest frame on a square, anchored foundation will usually serve better than a premium structure forced onto an unsuitable site.

The RHS frame-selection guidance is useful background, but the exact model's treatment and warranty matter more than a material slogan. Our separate wooden and aluminium guides cover those buying checks.