Attached vs detached pergola

The words get used loosely, and three quite different installations hide behind them.

A true attached pergola carries one edge of its roof on a ledger board or mounting beam fixed to the house, usually with two posts instead of four. The building takes a share of the vertical load and most of the wind uplift on that edge.

A lean-to or wall-mounted pergola is the manufactured version of the same idea: a kit designed from the start with a wall side, a pitched roof running away from the building and a defined flashing detail. PURPLE LEAF sells louvered pergolas in this configuration from 8 x 10 ft upward.

A freestanding pergola sited against the house keeps all four posts and all of its load in the ground, and simply stands close to the wall. Visually it reads as attached from inside the house; structurally it is a different object.

The third one is the option most people have not considered, and for the buy-it-for-life shopper it is usually the right one. Everything below is about why.

This is the finding that should drive the decision, and it is easy to miss because the number is right there in the listing.

Every published pergola wind rating on this site describes a freestanding, anchored structure. Backyard Discovery publishes up to 100 mph Pro-Tect tested, on the condition that the product is anchored as specified. PURPLE LEAF publishes 72 mph for the Athena when fully secured with expansion screws on a hardened floor, and 70 mph for the Caesar under normal installation. Those are the conditions the figures were measured under.

None of these manufacturers publishes a separate figure for a wall-mounted or attached configuration — not even the brands that sell one. We looked, on every collection and product page cited at the foot of this page, and there is no attached rating to quote.

That is not a scandal. Testing an attached configuration would mean testing somebody else's wall, which no manufacturer can do. But it has a hard consequence: the moment you attach, you own the rating. The figure in the listing describes a structure you no longer have, and there is nothing to hand a permit office, an HOA committee or an insurer. Wind ratings explained covers what a published figure is and is not worth.

A freestanding pergola's load path is four posts, four anchors and the ground. You can see all of it, and so can anyone you ask to look at it.

An attached pergola's load path runs through a ledger or mounting beam, through whatever fixings reach solid framing, into a wall assembly you cannot see without opening it up. Three things change, and all three are worse:

Attaching also moves the project into a different conversation with your building department, and this is consistent enough to plan around.

A freestanding pergola is typically treated as an accessory structure, and many jurisdictions exempt accessory structures below a footprint threshold. Bolting a structure to the house is typically treated as a structural alteration to the building itself — a different category, often with no size exemption, and sometimes requiring drawings.

That is the single biggest practical argument for freestanding, and it is an argument about time and paperwork rather than about engineering. It is also local: thresholds, exemptions and how an attached cover is classified all vary by jurisdiction, so it is a question to ask before you order rather than after. Pergola permits and HOA rules sets out the questions and the order to ask them in.

One more wrinkle worth raising with your insurer rather than with a forum: a structure fixed to the dwelling is often covered differently from a detached accessory structure, in both directions. Worth a five-minute call.

The comparison as published facts and structural consequences, not as a style preference.

Freestanding is the default, not a rule. Four cases where attaching genuinely wins:

Six things, in order. None of them is optional and the first one is not a formality.

A freestanding pergola set close to the wall is the answer that keeps nearly everything and gives up almost nothing, and it works because roof span and post span are different numbers.

The Yardistry 12 x 12 publishes a 12 ft roof over a 10 ft post base — a foot of overhang per side. Set that post line 10 ft off the house and the roof reaches to within about a foot of the wall. From inside, through a window, the shade line reads as continuous. Structurally, every load is still in the ground, the published anchoring requirement still applies as written, the warranty is intact and the permit conversation is the simpler one.

What you give up is that one-foot gap, which lets rain through at the wall, and the patio depth the post line occupies. If you can afford the depth, that trade is overwhelmingly worth making.

For the pergola categories themselves, start from the best louvered pergolas if you want shade on demand, best cedar and wood pergola kits if you want a repairable timber structure, or pergola vs awning if the real question is whether you want a structure at all.