The short answer
A trellis top adds height and softer screening while letting wind and light through; a solid top gives complete privacy but catches far more wind. Putting trellis on top of a fence raises the effective height for privacy — especially with climbing plants — and the open lattice lets air pass, so it puts much less strain on the posts than extending a solid panel. A solid top screens completely but acts as a sail and needs strong posts. Note that trellis counts towards your fence's overall height under UK permitted development (generally up to 2m in a rear garden). Choose trellis for height with wind resistance and planting; choose a solid top for total screening in a sheltered spot.
When a standard fence is not quite tall enough for privacy, the usual choice is to top it with trellis or to extend it with a solid section. They look and behave quite differently, especially in the wind.
Trellis vs solid top
- Trellis topAdds height, lets wind/light through
- Solid topFull privacy, catches wind
- Wind winnerTrellis (open lattice)
- Privacy winnerSolid (or trellis with climbers)
- Height ruleTrellis counts towards the 2m limit
What each option does
Both are ways to raise the effective height of a fence above the standard panel.
A trellis top is an open lattice panel fixed above the solid section, often around 30cm tall, though taller and shorter sizes exist. On its own it is see-through, but it is usually grown over with climbing plants — clematis, jasmine, honeysuckle, climbing roses — which fill the lattice to create a soft, green screen above eye level. The open structure lets wind and light pass through.
A solid top simply means extending the fence with more solid panel, or fitting taller panels, so the whole boundary is a continuous solid screen up to the new height. It blocks the view completely from the moment it goes up, with no waiting for plants to grow.
Privacy, wind and height rules
The trade-offs centre on privacy versus wind, plus the legal height limit.
- Privacy: a solid top gives immediate, complete screening. A trellis top is open at first and relies on climbing plants to screen — so it offers softer, gradual privacy that improves as the planting establishes. For screening an overlooking upstairs window, planted trellis can work well above eye level without the heaviness of a tall solid wall.
- Wind: this is the strongest argument for trellis. A solid top adds more sail area exactly where leverage on the posts is greatest, so it increases the load and the risk of the fence being blown down. The open lattice of a trellis lets air filter through, adding height with far less wind load.
- Height rules: under UK permitted development, a rear-garden fence is generally limited to 2 metres without planning permission, and trellis counts towards that total height. So a 1.8m fence with a 0.3m trellis on top would exceed 2m and may need permission. Plan the combined height to stay within the limit for your boundary, or check with your council.
| Factor | Trellis top | Solid top |
|---|---|---|
| Privacy | Soft/gradual (needs climbers) | Immediate and complete |
| Wind load added | Low — air passes through | High — extra sail area |
| Light to garden | Lets light through | Blocks light |
| Planting | Supports climbers | No |
| Counts to height limit | Yes | Yes |
Indicative comparison for adding height to a UK garden fence; check the height limit for your boundary before building up.
Looks, planting and structure
Appearance and gardening often tip the choice. A trellis top softens the look of a fence, breaks up a tall expanse of timber, and turns the boundary into a support for climbing plants and a feature in its own right. It suits gardeners who want greenery and a lighter, less boxed-in feel.
A solid top keeps a clean, uniform fence line and is the better answer where you simply want to block a view entirely and immediately, or where the planting to fill a trellis would not be practical.
Structurally, whichever you choose, the extra height increases the load on the posts, so the posts and their foundations matter. Trellis adds the least load, but a solid extension on a fence with old or shallow posts can overwhelm them in a storm. If you are adding a solid top, make sure the posts are strong (ideally concrete) and well set, or you may trade privacy for a collapsed fence.
Fitting a topper to an existing fence, and what the climbers need
One reason a trellis top appeals is that it can often be added to a fence you already have, without rebuilding it — provided the existing structure can carry the extra height. Trellis is light and is usually fixed either with fence-top extension brackets that bolt to the existing posts and carry a short additional post for the lattice, or by screwing the trellis to timber battens fixed to the panel frame and posts. The key check is the posts: adding height puts more leverage on them, so old, short or rotting posts may need replacing or strengthening with a concrete spur first, even for lightweight trellis. Extending with a heavy solid top makes that post check essential rather than optional.
If the plan is a planted trellis, the planting side matters as much as the carpentry. Climbers need something to climb and somewhere to root: vigorous, self-clinging or twining plants such as clematis, honeysuckle, star jasmine or climbing roses suit a lattice, but they want decent soil at the base, water while establishing, and tying in for the first season or two until they fill the gaps. That is why a trellis screen is gradual — it is really a fence-and-garden hybrid, and the privacy arrives as the plants mature. A solid top, by contrast, is pure carpentry: it screens the day it goes up, asks nothing of the soil, but gives nothing back to the garden either.
This is the deeper distinction behind the choice. A trellis top turns the top of the boundary into growing space and a softer, greener edge that changes through the year; a solid top turns it into a taller wall. Both add height and privacy, but one does it as part of the garden and the other as part of the fence — and the right answer often depends as much on whether you want to garden the boundary as on wind or sight lines.
Which should you fit?
Match the choice to your priorities:
- Choose a trellis top if you want extra height with good wind resistance, you like climbing plants and a softer, greener boundary, you want to let light through, or the garden is exposed and a solid extension would risk being blown down.
- Choose a solid top if you need immediate, complete privacy, the garden is sheltered, planting a trellis is impractical, or you want a clean continuous fence line — and you have strong posts to carry the extra height.
For most UK gardens wanting a bit more privacy, a planted trellis top is the practical, wind-friendly answer that also keeps the boundary within reasonable height once you account for the lattice in the total. Where total, instant screening is the goal and the spot is sheltered with sound posts, a solid top does the job. In both cases, check your boundary's height limit first, since trellis counts towards it, and make sure the posts can take whatever height you add.
Frequently asked questions
Does trellis on top of a fence count towards the height limit?
Yes. Under UK permitted development, trellis fixed on top of a fence counts towards the overall height, generally limited to 2 metres in a rear garden without planning permission. So a 1.8m fence with 0.3m of trellis would exceed 2m — plan the combined height or check with your council.
Is a trellis top better than a solid top in the wind?
Generally yes. A solid extension adds sail area where leverage on the posts is greatest, increasing the risk of the fence blowing down. A trellis top's open lattice lets air filter through, adding height with much less wind load, which is safer in exposed gardens.
How long does a trellis top take to give privacy?
On its own a trellis is open, so privacy depends on climbing plants growing through it, which can take a season or more to establish and fill out. A solid top gives complete privacy immediately. If you need instant screening, a solid extension is faster, but a planted trellis gives softer screening over time.
Sources & further reading
- GOV.UK — Planning permission for fences, walls and gates
- Jacksons Fencing — trellis and fence toppers
- Checkatrade — fencing cost guide
Figures on this page are typical UK ranges drawn from published sources and depend on your specific garden. They are guidance, not a quotation.