Greenhouse Installation Guide

Investing in a professional landscaper for the installation guarantees that the foundation is perfectly square. Even a few millimetres of misalignment in the base can lead to cracked glass or a frame that refuses to bolt together correctly.

What Does the Work Involve?

• Site Assessment: Evaluating sunlight exposure, wind protection, and proximity to water or power supplies.
• Ground Preparation: Excavating the area and levelling the soil to prevent future subsidence.
• Base Construction: Installing a solid foundation using concrete, paving slabs, or a dedicated perimeter plinth.
• Frame Assembly: Constructing the aluminium or timber skeleton according to manufacturer specifications.
• Glazing: Fitting glass or polycarbonate panels and securing them with clips, beads, or capping.
• Fixtures and Fittings: Installing doors, louvre vents, automatic roof openers, and internal staging.
• Sealing: Applying weather-resistant sealants to joints to ensure the structure is watertight.

Typical Costs

The costs below reflect the labour and secondary materials required for installation in 2025/26. Please note that these figures do not include the purchase price of the greenhouse kit itself.

Pricing is primarily influenced by the complexity of the frame and the type of glazing used. Toughened glass is heavier and more time-consuming to install than polycarbonate, while timber frames often require more precision than pre-drilled aluminium kits.

How Long Does It Take?

• Base Preparation: 1 day (plus drying time if using concrete).
• Small 6x4 Greenhouse: 1 day for a two-person team.
• Medium 8x6 Greenhouse: 1 to 2 days depending on the glazing system.
• Large/Orangerie Style: 3 to 5 days including internal fittings.

DIY or Professional?

Many greenhouses are sold as DIY kits, but they are notoriously difficult to assemble, often arriving with hundreds of identical-looking parts. A professional landscaper has the tools to ensure the base is perfectly level, which is critical for the structural integrity of the glass.

If you are using toughened or horticultural glass, professional installation is highly recommended to avoid breakages and potential injury.

If you plan on adding electricity for heating or lighting, you must hire a qualified electrician to comply with UK Building Regulations (Part P). Similarly, any permanent plumbing for irrigation should be handled by a professional to prevent leaks.

Choosing the Right Tradesperson

• Look for landscapers with specific experience in "outbuildings" or "garden structures."
• Check for public liability insurance (minimum £1 million) to cover any accidental glass breakage.
• Ask if they provide the base materials or if you need to source slabs/hardcore yourself.
• Question: "How do you intend to anchor the greenhouse to the base to prevent wind damage?"
• Question: "Do you offer a guarantee on the assembly work, specifically against leaks or rattles?"
• Red Flag: Avoid any contractor who suggests skipping a solid base and simply "pinning" the frame to the grass.

UK Regulations

• Permitted Development: Most greenhouses do not require planning permission if they are single-storey and under 2.5m high at the eaves.
• Positioning: Structures should not be placed forward of the "principal elevation" (the front of your house) without permission.
• Size Limits: In many areas, outbuildings should not cover more than 50% of the total garden area.
• Listed Buildings: If your home is listed or in a Conservation Area, always check with your local planning office first.

Common Problems

• Uneven Bases: Even a 5mm slope can cause the frame to twist, meaning glass panels won't fit or doors will stick.
• Wind Damage: Greenhouses acting like sails; if not bolted securely to a heavy base, they can be destroyed in a storm.
• Poor Drainage: Water pooling around the base can lead to timber rot or "heaving" in concrete during a frost.
• Insufficient Ventilation: Forgetting to install enough roof or louvre vents can lead to plant loss during UK heatwaves.

Frequently Asked Questions

Do I need a concrete base for my greenhouse?

While concrete is the most durable, a level base of paving slabs or a dedicated pressure-treated timber plinth is often sufficient for smaller models. The key is that it must be perfectly level and solid enough to bolt the frame down.

Should I choose glass or polycarbonate?

Toughened glass is the UK standard for longevity and light transmission. Polycarbonate is safer for gardens with children or pets and offers better insulation, but it is lighter and more prone to popping out in high winds if not fitted correctly.

Can a greenhouse be installed in winter?

Yes, but ground preparation is harder if the soil is frozen or waterlogged. It is often better to install the base in autumn and the structure in early spring before the growing season begins.

How much space should I leave around the greenhouse?

Ideally, leave at least 1 metre of space on all sides. This allows for easy cleaning, glass replacement, and ensures that nearby fences or hedges don't cast too much shade.

Will my insurance cover the greenhouse?

Most standard UK home insurance policies cover outbuildings, but you may need to specify the greenhouse if it is particularly expensive or contains high-value equipment like hydroponic systems.