Seat walls and low retaining walls in Missoula
Walls give a patio a finished edge and built-in seating, and on a hillside lot they create the level ground a patio needs.
The valley floor is flat, but plenty of Missoula homes aren't on it. Lots in the South Hills, up the Rattlesnake and along the edges of Grant Creek and Pattee Canyon can drop several feet from the back door to the fence. A low retaining wall can turn that slope into a level terrace for a patio, while a freestanding seat wall adds seating around a fire feature or along one side of the patio.
Which wall does what?
| Wall | Job | Notes |
|---|---|---|
| Seat wall | Freestanding seating beside a patio or fire feature | Built around seat height and finished with a cap |
| Raised planter | Holds soil for vegetables or perennials | Needs drainage holes or stone so water doesn't pool behind the block |
| Low retaining wall | Holds back soil to level part of the yard | Compacted base, drainage stone and a drain pipe at the bottom |
| Taller or loaded wall | Big grade changes, or walls below a driveway or slope | Ask whether a permit and an engineered design are needed |
When does a wall need a permit?
It depends on height, what the wall holds up and where it sits. Montana adopted the 2021 International Residential Code in 2022, and taller retaining walls, or walls that support a driveway, a slope or a building above them, can fall outside the permit exemptions. Inside city limits, ask the City of Missoula; elsewhere, the Missoula County Building Division. Missoula County also lists retaining walls among the structures that need a shoreline permit in shoreline areas, which matters on lots along lakes and streams.
How is a block wall built?
- A trench with a compacted gravel leveling pad and a buried first course
- Each course stepped back slightly as the wall rises, per the block maker's guide
- Clean drainage stone behind the block and a perforated pipe at the base
- Caps glued down so they stay put through freeze-thaw cycles
Why drainage behind the wall matters
Water that collects behind a wall pushes on it, and when that water freezes in January it pushes harder. Free-draining stone and a pipe with somewhere to go keep the pressure off. On a hillside, ask where the wall's drain will discharge, so it doesn't send water onto a neighbor's yard or straight down the driveway.
No two Missoula yards are alike, so the contractor sets a price only after seeing the site, checking the soil and slope, and going over the layout and paver style you want. We don't quote prices, and any figure mentioned on a first phone call is a rough starting point at best.
Where we connect you with help
Common questions
Do I need a permit for a retaining wall in Missoula?
Low walls often don't, but taller walls and walls holding up a driveway or slope can. Ask the City of Missoula inside city limits or the Missoula County Building Division outside it.
Can the wall block match my pavers?
Usually. Many manufacturers make wall block and caps in colors that coordinate with their pavers. Ask the contractor for samples.
Related services
More background: Missoula paver patio guide.
Ready for a patio that drains well and stays flat through a Missoula winter?
Call the number above and a Missoula-area paver contractor will talk through your yard and set up a visit.