12×20 pergolas

For shade: the Backyard Discovery Beaumont. It’s cedar on 6 by 6 inch posts with two structural cross beams, and the box includes steel anchor plates and concrete anchors, so a sound slab is all you need. The brand rates it for 100 mph winds once it’s anchored as the manual says, covers it for five years, and includes a PowerPort with three outlets and three USB ports. The catch is the open trellis roof: it gives dappled shade and nothing against rain, and Backyard Discovery says it doesn’t authorize changes such as adding clear panels. The cedar also needs a clear sealant every year.

For rain cover: Domi’s aluminum louvered pergola. The Brown and Gray versions come with curtains and netting, the White one is about $100 cheaper without them, and Domi covers the roof and frame for five years. It lists 72 mph winds and 15 pounds per square foot of snow, but only if the posts are fixed down. It ships by truck and needs two or three people, and Domi’s own page warns that the build can be a bit challenging. Our Domi review covers the brand’s terms.

For the lowest price on a roof that closes: the Erommy louvered pergola costs about $1,800 in white and $2,100 in grey, $1,000 or more less than the Domi. The catch is a one-year warranty and a return policy you should read before you order, which our Erommy review lays out. Erommy’s integrated-drainage version costs about $2,000 and lists a 70 mph wind rating.

For published wind and snow ratings: Paragon’s Lugano lists 82 mph and 17 pounds per square foot, and its Suprema lists 82 mph, 19 pounds and up to seven years of coverage with registration. They cost about $5,800 and $6,200 from Paragon, and Costco sells the Lugano at 12×20 for about $4,600, delivered but not set up. Our Costco pergola guide covers that route.

The prices fall into three groups because the roofs are three different products. Open cedar slats cost about $1,300 to $2,100 and give shade only. Louvers that close start near $1,800 and run to about $6,200 for Paragon’s, and the gap is mostly the warranty and published ratings. Erommy’s motorized version, with lights and side screens, costs about $7,300. Several of the cheapest listings are sold out at times, so check stock before you plan around one. For every louvered kit at any size, see louvered pergolas.

The name is the roof, not the room. Domi’s drawing gives 19.7 feet overall and two 9.3 foot gaps between posts, and Veikous’s cedar kit has about 17 feet between its end posts with a middle post between them. Each gap is about the size of a 10×10, enough for a round table for six or a sofa and two chairs, and the middle posts sit between the two groups. A single 18 foot open stretch isn’t what you get.

Height matters on a roof this long. Domi’s listing gives 7.2 feet of clear height under the beams, and Paragon lists a 7.8 foot pass-through height under the Suprema. If you’d rather have one open room, a 12×16 has a shorter span, and a hardtop 12×20 gazebo gives a solid roof at the same size.

The permit. The model building code most towns start from exempts a freestanding structure under 200 square feet, and a 12×20 is 240. Only 4 of the 24 cities and counties in our permit guide clear a freestanding open one of this size without a permit. Attach it to the house, or add a solid roof, and the answer changes again, so ask your building department first.

The base. Six posts need a solid footing. Backyard Discovery recommends a concrete patio 4 to 6 inches thick or footers 12 inches square and 18 inches deep. With no slab, Angi puts a new one at about $600 per 100 square feet, so roughly $1,450 under a 12×20. Paragon lists concrete, or a wood deck or pavers with concrete footings.

The deliveries. A 12×20 ships in several boxes: four from Backyard Discovery, three or four from the cedar brands, eight for Erommy’s curtain model. Some brands warn the boxes may arrive on different days. The complaints that come up again and again in low-star reviews, including Costco’s Paragon page, are about damaged or missing parts and slow fixes, not about wind. Open every box and count the parts before you start building.

The warranty on the roof. Backyard Discovery and Domi give five years on the structure, Paragon’s louvered kits four to seven, Erommy and Kozyard one, and Veikous six months. A roof this large is the part most worth having covered.