Covered decks and pergolas in Missoula
Shade turns a hot deck into one you'll actually use on a summer afternoon. Here's what to know before adding a roof or a pergola.
Missoula summers are dry and bright, and the city's record high is 107°F. An open, west-facing deck can be too hot to sit on in late afternoon. A pergola filters the sun. A solid roof blocks it entirely and keeps rain and snow off part of the deck as well.
Pergola or solid roof?
- Pergola. An open frame of beams and rafters that gives partial shade. Lighter and simpler, but it doesn't keep rain off. Shade cloth or adjustable louvers can add more cover.
- Solid roof. Tied into the house or standing on its own posts, with shingles or metal. Full shade and weather protection, but it's real structural work that has to carry snow.
What does snow load mean for a deck roof?
Any roof over a deck has to be designed for local snow. A Montana code summary lists a 40-pound-per-square-foot ground snow load for Missoula, taken from the state's table for incorporated cities, and snow drifting off a taller roof can add more. That weight runs down through the posts to the footings, so a covered deck usually needs larger posts and footings than an open deck.
Can I add a roof to the deck I already have?
Sometimes, but most existing decks weren't built to hold one. A builder will check whether the footings and framing can take the added load or whether new posts and footings are needed. If you're building a new deck and think you might want a roof someday, ask to size the footings for it now.
Permits
Published summaries of City of Missoula rules say covered decks need a building permit. Outside city limits, check with the Missoula County Building Division. Your builder should handle the application or tell you what's required.
Smoke season and screens
Late-summer wildfire smoke can make sitting outside unpleasant some years, which is one more reason people want a covered space they can close in. Once there's a roof, some owners add screens or plan for a future porch. That changes the design, so bring it up early.
Roof material near the trees
If the house backs onto pine or open grass, ask about a noncombustible roof surface and how leaves and needles will be kept out of gutters and corners. Firewise guidance in the deck guide applies to deck roofs too.
Every deck is priced by the builder after a site visit, once they've measured, looked at the ground and the house, and talked through materials with you. We don't quote prices, and any figure you hear before that visit is a rough guess.
Where we connect you with help
Common questions
Does a pergola need a permit in Missoula?
It depends on size, whether it's attached to the house and whether it has a solid roof. Check with the City of Missoula's Development Services, or Missoula County outside city limits.
Will a deck roof hold Missoula snow?
It has to be designed for it. Ask the builder what snow load the design uses and how the posts and footings are sized.
Related services
More background: Missoula deck guide.
Thinking about a new deck, or worried about the one you have?
Call the number above and a Missoula-area deck builder will talk through what you need.