Trellis Calculator — Panels, Clips & Posts

Standard UK trellis panels are 1.83m (6ft) wide, matching standard fence panels. They come in a range of heights — typically 0.3m, 0.6m, 0.9m, 1.18m (around 4ft), 1.5m (5ft) and 1.83m (6ft). The most popular size for fence toppers is 1.83m x 0.3m or 1.83m x 0.6m. For freestanding garden screens, taller 1.5m or full 1.83m x 1.83m panels are commonly used.

Trellis is attached to fence posts using trellis clips (also called U-brackets or fence panel clips). You need two clips per panel — one on each post. For concrete posts, use clips that bolt around the post. For timber posts, screw-fix clips or simply screw through the trellis frame into the post. Always use galvanised or stainless steel fixings.

In England and Wales, if adding trellis to an existing fence takes the total height above 2 metres, you may need planning permission. For fences fronting a highway, the limit is 1 metre total. For example, a 1.83m (6ft) fence with a 0.3m trellis topper would be 2.13m — technically over the 2m limit. Check with your local council if in doubt.

Diamond (diagonal) pattern trellis is best for climbing plants as it provides more attachment points at various angles. Square pattern trellis is better for a clean, modern look. For heavy climbers like wisteria or climbing roses, use heavy-duty trellis with thicker laths (at least 25mm). Pressure-treated softwood is the most common material, while hardwood lasts longer.

Yes, trellis panels can be used as freestanding garden screens for privacy or to create garden rooms. They need their own posts, set in concrete at 600mm deep minimum. Use 75×75mm or 100×100mm timber posts. Freestanding trellis catches the wind, so ensure posts are well concreted in. For exposed sites, consider using lattice with wider gaps to allow wind through. Use our Concrete for Fence Posts Calculator to work out the postcrete needed for each post.