Louvered Pergola Guide: Aluminum Kits, Motorized Roofs, Sizes, Ratings and Cost

Louvered pergola wind and snow ratings, compared

A louvered pergola is a freestanding frame, usually aluminum, with a roof of slats you can rotate. Closed, the slats overlap and send rain into gutters; open, they let light and hot air through. The roof is what you pay for, and it is also what wind and snow act on, so the published ratings are the first thing to compare.

The numbers vary a lot between kits that look alike. The table lists ratings the manufacturers publish. Mirador marks its figures as valid with professional assembly and anchoring, and Purple Leaf's manual gives its 72 mph figure for a fully secured pergola. Treat every rating as conditional on the anchoring in the manual.

Aluminum vs steel louvered pergolas

Many kits use aluminum posts; the difference is the beams and louvers. Galvanized steel louvers rely on their coating to resist rust. Aluminum louvers do not rust and weigh less, which leaves more of the structure's capacity for snow and wind.

Within one brand you can see the effect. Mirador's all-aluminum 111DA is rated 102 mph and 26.6 psf, the aluminum frame with steel louvers (111S) 90.2 mph and 20.8 psf, and the steel 80S 78.5 mph and 15.7 psf. Domi says the same thing in its own FAQ: its galvanized steel roof has lower snow resistance than all-aluminum pergolas. If you live where it snows or blows, pay for aluminum louvers.

Manual crank vs motorized louvers

A crank or lever is enough for most 10x10 and 10x13 kits: you set the louvers a few times a day at most. Motorized louvers earn their price when the roof is large, high or split into several sections, or when you want the roof to close on its own when rain starts. Budget for power: Angi lists $150 to $260 to add an outdoor outlet if you do not have one near a post.

Louvered pergola sizes: 10x10, 10x13, 12x16 and 12x20

Kit sizes refer to the roof, not the clear space between posts. Outsunny's 10x13 aluminum louvered pergola, for example, measures 155.5 x 118 in overall but 147.75 x 110.25 in between columns. Measure your furniture layout against the inside dimension and leave walking room around the table.

10x13 is the size you find across brands: Mirador, Domi, Purple Leaf and Outsunny all sell one. Above about 12x16 the roof crosses 200 sq ft, which is where HomeGuide notes some cities start requiring a permit.

Are louvered pergolas waterproof?

Closed louvers shed rain, but most kits are sold as water resistant, not watertight. Purple Leaf's manual lists its 94AS as water resistant; its 10x13 has a hidden gutter, and each louver has drainage grooves that send water to the frame and down the posts. Domi channels rainwater through the roof and beams down its four pillars into collection basins, and Outsunny lists a hidden drainage system.

Two things decide how dry you stay. First, wind-driven rain still blows in from the sides, so add side curtains on the weather side. Second, every post that drains water dumps it at its base. Place the pergola so that water runs away from the house and off the slab, not toward a door. The pergola for rain guide compares louvered, fixed and canopy roofs if staying dry is the main goal.

Louvers open or closed in wind and snow

Follow your own manual here, because instructions differ. Purple Leaf's 94AS manual says to keep the louvers fully closed in heavy rain or strong wind, to keep them open in heavy snow or ice so snow does not build up, and not to adjust the roof in windy conditions.

Compare the snow rating with the design snow load for your address, which the local building department can give you. If the kit's rating is lower, clear snow early or pick a stronger model. For exposed sites, the high-wind pergola guide covers anchors, post sizes and which shade types to avoid.

Permits, anchoring and freestanding vs attached

Most louvered pergola kits are freestanding: four posts on base plates bolted down. Purple Leaf tells owners to secure the pergola to a stable foundation with the provided expansion screws, and Outsunny includes ground stakes and expansion screws. Expansion anchors need solid concrete of adequate thickness. On pavers, a wood deck or soil, ask the manufacturer what base the published wind rating assumes before you buy.

Attaching a louvered roof to the house means a ledger into the wall framing, flashing and almost always a permit and inspection. Freestanding kits often need one too: HomeGuide puts the average permit at $60 to $150 and notes some cities require none unless the structure is over 200 sq ft. Call the building department with the size and height before you order.