Leviathan Slatted Back Diamond Corner Pergola 3m x 3m | 120mm Posts | Smart Seal | Nationwide Installation Included

Leviathan Slatted Back Diamond Corner Pergola – 3m x 3m | 120mm Posts | Smart Seal

Take the iconic Leviathan Diamond Corner Pergola to the next level with the Slatted Back version — featuring two integrated slatted timber panels at the rear as standard. Built by Dunster House from slow-grown, pressure treated spruce with imposing 120mm x 120mm posts, this is the premium corner pergola for those who want a defined, partially enclosed outdoor room straight out of the box.

The slatted back panels create a natural sense of enclosure and privacy at the rear of the structure, allowing light and airflow to pass through while screening the space from neighbours or boundaries. They also provide a beautiful frame for climbing plants, adding a living, organic element to your garden feature over time.

Finished with Smart Seal timber sealant and backed by a 10-year guarantee against rot and insect infestation, the Leviathan Slatted Back is engineered to perform beautifully through the British seasons for years to come.

🌟 The price includes professional nationwide installation and Smart Seal timber treatment — both included free of charge. Our experienced fitting teams install across the whole of Mainland UK, handling everything from delivery to final fitting.

Key Features

• ✅ Two slatted timber back panels included as standard — privacy and enclosure from day one
• ✅ Imposing 120mm x 120mm upright posts — exceptional structural strength and premium visual impact
• ✅ Distinctive diamond roof design — architectural elegance that elevates any garden
• ✅ Fully pressure treated slow-grown spruce — long-term rot and insect resistance
• ✅ Smart Seal timber treatment included free of charge — superior moisture and UV protection
• ✅ 10-year guarantee against rot and insect infestation
• ✅ Nationwide installation included as standard — anywhere across Mainland UK, free of charge
• ✅ Corner-fitting design — maximises use of garden corners and boundary spaces
• ✅ 7.42m² internal area — generous usable space for dining, entertaining, or relaxing
• ✅ Pre-cut, pre-notched, planed timber — precision engineered for a clean, professional finish
• ✅ All fixings supplied — everything needed is included

Specifications

• Overall External Dimensions: 3.321m x 3.321m (10' 10.75" x 10' 10.75")
• External Width: 3.040m (9' 11.75")
• External Depth: 3.040m (9' 11.75")
• Internal Width: 2.724m (8' 11.25")
• Internal Depth: 2.724m (8' 11.25")
• Internal Area: 7.42m²
• Overall Height: 2.350m (7' 8.25")
• Internal Eaves Height: 2.260m (7' 5")
• Upright Posts: 120mm x 120mm
• Slatted Back Panels: 2 (included as standard)
• Timber: Slow Grown Spruce (Fully Pressure Treated)
• Timber Finish: Smart Seal (included)
• Guarantee: 10 Years against Rot and Insect Infestation
• All sizes quoted are nominal. All fixings supplied. Timber is pre-cut, pre-notched, and planed.

Why Choose Bespoke Oak and Slate?

At Bespoke Oak and Slate, we supply and install premium Dunster House garden structures across the UK. Every Leviathan Slatted Back order includes professional installation and Smart Seal timber treatment as standard — completely free of charge. No hidden costs, no surprises — just a beautifully installed, fully treated pergola ready for you to enjoy.

Frequently Asked Questions

What are the slatted back panels?

The two slatted timber back panels are integrated into the rear of the Leviathan structure as standard on this version. They consist of horizontal timber slats that create a natural screen — providing privacy and a sense of enclosure while still allowing light and airflow through. They also make an excellent support for climbing plants such as roses, jasmine, or clematis.

How does this differ from the standard Leviathan Diamond Corner Pergola?

This version comes with two slatted timber back panels included as standard, giving you immediate rear privacy and enclosure without needing to order additional panels separately. The posts, dimensions, roof design, Smart Seal finish, and all other specifications are identical to the standard Leviathan.

Does the price include installation?

Yes — professional nationwide installation is included in the price, free of charge. Our experienced fitting teams cover the whole of Mainland UK. The price you see is the price you pay — fully installed, no extras.

What is Smart Seal and is it included?

Smart Seal is a premium timber sealant that provides a superior protective barrier against moisture penetration, UV damage, and weathering. Smart Seal application is included free of charge with every order — applied by our installation team as part of the fitting process.

Do you install anywhere in the UK?

Yes. We install anywhere across Mainland UK at no extra cost. From Cornwall to Caithness, our professional teams will come to you regardless of your location.

Can I add more panels to this pergola?

Yes — additional wall panels (half-height timber, full-height timber, or half-height timber & glass) are available as separate add-ons. All panels must be ordered and fitted at the time of your original installation — our team fits everything in a single visit.

Why does the Leviathan have 120mm posts?

The 120mm x 120mm upright posts are significantly larger than those on standard pergolas, providing exceptional structural rigidity, a premium heavyweight appearance, and the ability to support wall panels, roofing options, and climbing plants without any flex or movement.

Is the timber pressure treated?

Yes. All timber is fully pressure treated slow-grown spruce, providing long-term resistance to rot and insect infestation, and finished with Smart Seal for additional moisture and UV protection. Backed by a 10-year guarantee against rot and insect damage.

What is the internal usable space?

The Leviathan Slatted Back offers a generous 7.42m² internal area, with an internal width and depth of 2.724m (8' 11.25") each — plenty of room for outdoor dining furniture, a sofa set, or a hot tub enclosure.

Does this pergola need planning permission?

In most cases, a pergola of this size falls within permitted development rights and does not require planning permission, provided it meets standard conditions. We always recommend checking with your local planning authority if you are unsure.

What is the guarantee?

The Leviathan Slatted Back comes with a 10-year guarantee against rot and insect infestation on the pressure treated timber, provided the care instructions supplied by Dunster House are followed.