Two posts against the house, or four posts in the garden. That is the only structural difference, and it decides where the pergola can go, how deep it can be, how much load the wall has to take, and how you arrange furniture under it.
Both versions carry the same roof. The choice is about your site, not about the product.
If even the two front posts are more than you want, the third option is a wall-mounted retractable patio awning. Nothing reaches the ground at all, which costs you the depth and the rain protection a framed roof gives you.
See the wall-mounted and freestanding versions of our retractable pergola
The difference in one line
Wall-mounted uses the building as its rear support and stands on two front posts. Freestanding stands on four posts and leans on nothing.
Everything below follows from that.
What wall-mounted gives you
Floor space stays clear. Two posts instead of four means fewer things to walk around, which matters on a narrow patio where a rear post would sit exactly where the chairs want to go.
It reads as part of the house. The structure stops at the wall rather than standing in the middle of the garden like a separate building. On a terrace attached to a living room, that continuity is usually what people want.
The rear span needs no footing. The load at the back goes into the building rather than into the ground, so there is less digging and less concrete at the back of the frame. The two front posts still need proper fixing.
It fits tight sites. A wall-mounted unit can sit close to the building, which is often the only configuration that works between a house and a boundary fence.
The catch is that the wall has to be suitable. More on that below.
What freestanding gives you
It goes where the wall is not. Over a pool deck, out on a lawn, on a rooftop terrace, in the middle of a courtyard, anywhere the building is not available or not yours to drill.
It can go deeper. A freestanding frame spans front to back on its own posts, so projection is set by the frame design rather than by how far you are willing to cantilever off a wall. If you want to cover a dining table plus a lounge area, that depth matters.
It can be linked. Wider areas are covered by putting units in a row under one continuous roof. This is how restaurant and hotel terraces get covered, and it works the same way in a garden.
It needs four footings. Each post has to be anchored to something solid. That is the main work and the main delay on a freestanding install.
The wall is usually the deciding factor
Before you fall in love with a wall-mounted layout, look at the wall.
Things that rule a wall out, or complicate it:
- Render or cladding over something unknown. You need to know what is behind the surface before anchors go in.
- A thin or single-skin wall that was never meant to carry a frame.
- Downpipes, meter boxes, vents, boiler flues, outside taps sitting exactly where the wall plate needs to go.
- Windows and doors that would be crossed by the plate, or blocked by a post.
- Insufficient height between the patio and the eaves, gutter or first-floor sill.
- A shared or rented wall you cannot fix to.
Any one of these can push the project to freestanding, and freestanding is not a downgrade. It is the version that does not care what the house is made of.
Projection is the number people get wrong
With a wall-mounted frame, the front posts define how far the roof reaches. Push them out and the roof gets deeper, but the load on the wall plate and on those two posts grows with it.
With a freestanding frame, the posts are at the corners, so the same footprint is carried by four points instead of two plus a wall. That is why freestanding tends to be the answer when the covered area is large.
If you are unsure which side of the line you are on, send the width and the projection you want. That is enough to say whether the wall version is sensible.
Water still leaves through the posts
Both versions drain the same way: rain collects in the beams, runs into the posts, exits at the base. Which means post position is not only a furniture question. Each post puts water on the ground at its own corner, so think about where that water lands. Onto a slope, onto gravel, or onto a drain is fine. Into the corner where the patio meets the house wall is not.
Commercial terraces
Restaurants, cafes and hotels usually go freestanding and link units, because the space is not tied to a wall and the layout has to survive being rearranged. Wall-mounted comes into its own over a street-facing frontage where the building provides the rear support and the pavement stays clear.
What we ask before quoting
The questions are the same every time, and they are the ones worth answering in one message:
- Width and projection you want to cover.
- Wall-mounted or freestanding, or "not sure" with photos.
- What the posts will be fixed to: concrete, pavers, decking, or soil.
- Any obstructions at the wall line: pipes, vents, doors, lights.
- Where you are, since shipping shape affects how the frame is packed.
Can I change my mind later and convert one to the other? Not practically. The frame, post count and wall plate are made for one configuration, so the decision is made at order time.
Is freestanding less stable? A correctly anchored four-post frame is stable on its own. The difference is where the load goes, not whether the structure holds.
Can a wall-mounted pergola go on a wooden wall? Sometimes, with the right fixing and a wall that can take the load. It is a question for a contractor who can see the wall rather than one to settle by email.
What if my patio is not level? Post heights can be set to suit small differences. Large slopes are a drainage and layout question, so send photos.
Does either version need planning permission? It depends on where you are and how close the structure sits to a boundary. Our post on pergola permits covers what to check before you order.