The Ultimate T-Shaped Greenhouse (Free Installation Included)
Swallow Mallard Greenhouses combine Victorian-style elegance with Scandinavian engineering. The distinctive T-shaped design gives you 8ft 9" of growing width plus a separate porch area — perfect for creating two distinct zones in your garden. You'll find models from the compact Swallow Mallard 8x11 Greenhouse starting at £9,829 to the expansive Swallow Mallard 8x32 Greenhouse at £15,089.
The T-shape design is its greatest strength. You can use the main 8ft 9" greenhouse section for serious growing whilst the porch area (available in 4ft or 6ft depths) becomes your potting bench space, seating area, or even a garden office extension. Browse our complete Swallow Greenhouses collection to compare the Mallard against other ranges.
Choosing Your Mallard: A 3-Step Guide
- Standard (Oiled): The greenhouse arrives with a UV-protectant oil finish. This needs annual re-treatment to maintain its colour.
- Painted: Upgrade to one of 10 painted colours (£500–£800 extra) for protection lasting 3–5 years between repaints. Popular colours include Sage, Slate Grey, and Heritage Green.
Built to Last: Standard Specifications
All Swallow Mallard greenhouses include 58mm x 32mm glazing bars, 12mm tongue-and-groove boards fixed with stainless steel nails, and an integral PVC damp barrier. They also include guttering, downpipes, automatic vents, and a mortice door lock. Our greenhouse growing guide for beginners helps you make the most of your new space.
Frequently Asked Questions
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How much do Swallow Mallard Greenhouses cost?
Swallow Mallard Greenhouses range from £9,829 for the 8x11 model to £15,089 for the 8x32 model. All prices include professional delivery and installation across UK mainland. You'll pay just 20% deposit when ordering, with the balance due after installation completes — not before. Optional extras like painted finishes (£500–£800) and porch extensions (£1,200–£1,800) can be added.
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What makes the T-shaped design useful?
The T-shape gives you two distinct zones in one structure. The main 8ft 9" greenhouse section provides serious growing space with full-length staging, whilst the 4ft or 6ft porch creates a separate area for potting, tool storage, or even a garden seating spot. This creates significantly more functional space compared to a standard rectangular greenhouse of the same footprint.
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How long does Thermowood last?
Thermowood greenhouses last 25–30 years with minimal maintenance. The heat treatment process removes moisture and resins that cause rot and warping. The timber itself won't decay even if you skip treatments — the standard oiled finish (annual re-treatment) and painted finish (repaint every 3–5 years) are purely to maintain the aesthetic and colour.
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What's included as standard with Swallow Mallard Greenhouses?
Every Swallow Mallard includes toughened safety glass throughout, automatic roof vents (4–6 depending on size), full-length slatted staging down one side, guttering and downpipes, a mortice door lock, and a PVC damp barrier. Professional delivery and installation are included in the price for UK mainland locations. Optional extras include high-level shelving (£133), porch extensions (from £597), and additional staging.
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Do I need planning permission for a Swallow Mallard?
Most Swallow Mallard Greenhouses don't need planning permission under permitted development rules. Your greenhouse must be under 3m high (all models qualify), sit at least 2m from boundaries, and not cover more than 50% of your garden. Always check with your local planning authority before ordering, especially in conservation areas or with listed buildings.
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Swallow Mallard vs Cygnet vs Swan — which is best?
It depends on your space and needs:
- Mallard: 8ft 9" wide with a 6ft 8" single-door porch. Ideal for most gardens.
- Cygnet: Narrower at 6ft 8" width (also with 6ft 8" porch) for tighter spaces.
- Swan: The largest, at 8ft 9" wide throughout including an 8ft 9" double-door porch for easy wheelbarrow access.