Once an existing fence isn't quite tall enough, there are really two routes: extend the solid fence height, or add a trellis topper. They behave differently in wind and under planning rules, so it's worth understanding both before choosing.
Extending with solid panels
Best for: Where full solid privacy is the priority and posts can take the extra load
- Maximum achievable privacy for the extra height added
- Consistent solid appearance matching the fence below
- Taking a boundary over roughly 2m generally needs planning permission
- Adds significant extra wind load onto existing posts, which may not be rated for it
Trellis topper
Best for: Adding modest height and softening a boundary without overloading existing posts
- Adds useful height while staying visually lighter, reducing wind load compared with solid panels
- Supports climbing plants for further natural screening over time
- Often a simpler retrofit onto an existing sound fence line
- Less direct privacy than solid boarding at the same height
- Still needs checking against the overall height limit for your boundary
Side by side
| Solid extension | Trellis topper | |
|---|---|---|
| Privacy added | Maximum | Moderate, improves with planting |
| Wind load added | High | Lower |
| Planning consideration | Height limits apply | Height limits still apply |
| Fits onto existing posts | May need reinforcing | Usually more feasible |
Which should you choose?
Check your existing posts and overall height first — see our planning rules guide — since both options must respect the same boundary height limits.
If posts are sound but not rated for much extra load, or you'd like planting to soften the boundary over time, a trellis topper is usually the more practical retrofit.
Trellis toppers are the lower-risk, lower-load way to add height and some privacy; solid extensions give more privacy but demand sound, well-founded posts.
Want more height or privacy on an existing fence?
We'll check your current posts and boundary height allowance, then recommend the safest way to add what you need.
Frequently asked
Do I need permission to add a trellis topper?
The same overall height limits apply to trellis as to solid fencing — check our fence height and planning rules guide before adding one.
Will my existing posts take a trellis topper?
Usually, since trellis is lighter than solid boarding, but we check post condition on site before recommending it.
Can climbing plants damage the trellis or fence?
Heavy, mature climbers add real weight and wind sail over years — worth keeping them trimmed as covered in our fence maintenance guide.
Is a trellis topper as private as extending with solid panels?
Not immediately, but planting through it closes the gaps over a season or two, getting closer to full privacy.