A concrete patio around Portland should sit on a compacted crushed-rock base, slope gently away from the house, and have control joints plus an isolation joint at the foundation. Plan where runoff goes, choose a finish with grip for wet months, and check zoning, permit and HOA rules, especially if you'll add a roof later.
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A concrete patio in Portland is often built with the wet season in mind. Many homeowners pair a slab with a roof or pergola so they can use it from October to May, and almost everyone wants it to drain fast after a shower. The basics that make a patio last are the same anywhere: a compacted base, slope away from the house and well-placed joints. Here they just get tested more often.
Planning the patio
- Size for real use. Lay out the table, grill or fire feature and leave room to walk around them.
- Cover now or later. If you might add a roof, pergola or outdoor kitchen, say so up front. Posts need footings, and covered structures above a certain size need a building permit.
- Shade and moss. North-facing and tree-shaded patios stay damp and grow moss and algae. Texture and drainage help keep them safer underfoot.
- Access. Backyards behind narrow side yards, common on older Portland lots, may need concrete pumped or wheeled in.
Drainage comes first
A patio should slope gently away from the house so water runs off instead of toward the foundation or into a basement. Then think about where that water goes. Valley clay in much of Washington County drains slowly, and OSU Extension notes that Western Oregon clay soils turn sticky and heavy when wet. A patio that sends roof and slab runoff into a low spot can create a new soggy corner or a wet crawlspace. In the City of Portland, the Bureau of Environmental Services runs Clean River Rewards, a program that rewards managing roof and paving runoff on your property, so it's worth asking how a new slab affects your stormwater setup.
Base, thickness and joints
Patios are commonly about four inches thick over a compacted crushed-rock base. Soil next to the house is often backfill from when the foundation was built, and it can settle under a new slab if it isn't compacted or replaced. Control joints divide the slab into roughly square panels. Where the patio meets the house, an isolation joint lets each move on its own.
Finish options
- Broom finish: simple, economical and good traction in the rain.
- Exposed aggregate: the surface paste is washed off to show the stone, a long-standing Pacific Northwest favorite for grip.
- Stamped or colored concrete: patterned to look like stone or slate. See stamped and decorative concrete.
- Smooth trowel: attractive but slick when wet, so it's uncommon outdoors here.
Permits and HOAs
The City of Portland's guidance for an on-grade concrete patio on private property is to contact Planning and Zoning to find out whether a zoning permit is needed, and covered patios over a size threshold need a building permit. Suburbs set their own rules, and some limit how much of a lot can be paved. Many newer subdivisions in Hillsboro, Beaverton and Tigard have HOA approval steps for patios and colors. Check both before the pour is scheduled.
Timing
Patios are usually poured in the drier months, roughly late spring through early fall, when the base can be prepared without mud. Rain during finishing can damage the surface, so good contractors watch the forecast and have covers ready. See our guide to pouring concrete in Portland weather.
Questions to ask
- How will the patio drain, and where will the water end up?
- What base material and depth are included?
- Where will the joints go, including at the house?
- How will you get concrete to the backyard and protect the lawn?
Ready to plan it? Request a patio contractor and share a photo of the space.
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Frequently asked questions
Do I need a permit for a concrete patio in Portland?
For an on-grade patio on private property, the City of Portland says to contact Planning and Zoning to find out whether a zoning permit is needed. Covered patios over a size threshold need a building permit. Other cities set their own rules.
What patio finish is best for Portland's rain?
Broom and exposed aggregate finishes give the best traction when wet. Stamped concrete can work with a textured pattern and a slip-resistant sealer. Smooth troweled finishes are slick when wet and are uncommon outdoors here.
How do I keep moss off a concrete patio?
Good drainage, more sun and regular sweeping help. Shaded patios usually still need periodic cleaning. Ask your contractor which cleaners are safe for any sealer on the slab.
Sources and further reading
- Oregon Construction Contractors Board: license requirements
- Oregon CCB: Guide to home improvement contracts
- Portland Bureau of Transportation: driveways
- Portland Bureau of Transportation: sidewalk repair notices
- Portland Permitting & Development: outside work permits
- Portland Bureau of Environmental Services: Clean River Rewards
- Portland Water Bureau
- City of Gresham Permit Services
- OSU Extension: clay soil challenges for Oregon gardeners
- DOGAMI: landslide hazard and risk study, Multnomah County (IMS-57)
- National Weather Service Portland
- Oregon 811: call before you dig
- American Concrete Institute (ACI)
- Portland Cement Association (PCA)