Wall-mounted or freestanding pergola?

A wall-mounted pergola uses the house wall instead of two posts. That saves posts and gives a covered link from the back door. It also brings the wall, the damp-proof course and possibly the planners into the job.

How a wall-mounted pergola is held up

The frame is fixed to a wall plate or ledger bolted to the house, with posts at the outer edge only. Whether your wall can take it depends on what it is made of and its condition. Solid brick, cavity walls, render over block, and timber cladding all need different fixings. Follow the maker's fixing instructions for the wall type, and ask a builder or structural engineer if the wall is cracked, rendered over something unknown, or a cavity with no fixing guidance from the maker.

What to check on the wall

• Height. The ledger has to clear door and window heads and sit below upstairs sills, vents and the house eaves. That often fixes the pergola height before planning does.
• Damp-proof course and air bricks. Do not bridge them with the base or cover vents.
• Water. A solid or louvred roof sends rain towards or away from the wall. Where it meets the wall it needs flashing or a seal, and the gutter must discharge somewhere sensible. Water running down the house wall is the classic problem.
• Services. Check for cables and pipes before drilling.

Planning

A freestanding pergola is usually read against the outbuilding limits. One fixed to the house may be treated differently. The Planning Portal outbuildings guide says verandas and balconies are not permitted development, and a roofed structure on the house can be assessed as an extension. A roofed, wall-mounted design is the one to raise with the council before you order. See planning permission.

Freestanding, side by side

	Wall-mounted	Freestanding
Posts	Two at the outer edge	Four or more
Base	Outer posts only	All posts
Planning	May be treated as an extension or veranda	Usually read against outbuilding limits
Wind	Depends on the wall fixing as well as the posts	Depends on posts and base
Siting	Against the house	Anywhere suitable, within the limits

Can I fix a pergola to a rendered wall?

Sometimes, but the fixing goes through the render into what is behind it, and the render must be sealed afterwards. Follow the maker's instructions and ask a builder if you do not know what the wall is made of.

Does a wall-mounted pergola need building regulations approval?

It depends on what it is and how it is attached. Any new electrical circuit is a separate question under Part P. Ask building control if you are adding a roof against the house.