A concrete patio in the Denver metro should sit on a compacted gravel base, slope slightly away from the house, and have control joints plus an isolation joint at the foundation. On swelling clay, keep sprinkler spray and downspout water away from the slab edges. Check HOA approval and your city's permit rules before the pour.
Last updated
A concrete patio is one of the simplest ways to get more out of a Denver backyard, whether it's a plain slab off the kitchen door or a larger space with steps, a fire pit area and a decorative border. Patios here face the same forces as every other slab on the Front Range: clay that moves with moisture, winters that freeze and thaw, and intense summer sun. Building for those conditions is what keeps a patio flat and good-looking.
Planning the space
- Size it for real use. Lay out the table, grill and chairs you plan to use and leave room to walk around them.
- Sun and heat. At Denver's elevation, sun is strong. West- and south-facing slabs heat up in summer afternoons, while north-facing patios can hold snow and ice for days after a storm. Color, texture and shade all affect comfort and safety.
- Access. Fenced backyards, narrow side yards and alley-loaded lots may need concrete pumped or wheeled in, which affects cost and scheduling.
- Future plans. If you might add a pergola, covered roof or hot tub later, say so. Posts and heavy loads may need footings, and roofed structures generally need a building permit.
Water and swelling soil
On expansive clay, water is the enemy of a flat patio. CSU Extension advises grading so water drains away from the house and keeping sprinkler spray and thirsty plantings back from the foundation. Patios sit right in that zone. A patio should slope slightly away from the house, and the water it sheds should have somewhere to go besides a flower bed that gets soaked every week. Watch for sprinkler heads that spray onto the slab or soak the soil along its edges, and keep downspout extensions in place. Denver Water's summer watering rules limit how often and when lawns can be watered, which is also a good reason to set irrigation zones carefully around new concrete.
Base, thickness and joints
Patios are commonly about four inches thick over a compacted gravel base. Soil next to a foundation is often backfill that was placed when the house was built and may be looser than the native ground, so it needs compaction or replacement before a slab goes on it. Control joints divide the slab into roughly square panels so shrinkage cracks form along the joints, and an isolation joint where the patio meets the house lets the two move separately. Where soils are known to be highly expansive, some homeowners choose to leave a patio free-floating rather than doweling it to the foundation, so that soil movement under the patio doesn't push on the house. Ask your contractor which approach fits your lot.
Finish options
- Broom finish: economical and slip-resistant when wet or frosty.
- Exposed aggregate: the surface paste is washed off to reveal stone, adding texture and traction.
- Stamped or colored concrete: patterned to resemble flagstone, slate or wood. See our stamped and decorative concrete page.
- Smooth trowel: looks clean but gets slick with snow and ice, so it's uncommon outdoors here.
Permits and HOAs
Whether a ground-level patio needs a permit depends on your city or town, and some limit how much of a lot can be paved. HOAs are common across the metro, especially in Highlands Ranch, Parker, Castle Rock and newer parts of Aurora, and many require architectural approval before any exterior hardscape goes in. Get approvals before the contractor schedules the pour.
Questions to ask
- How will the slab drain, and where will water go after it leaves the patio?
- What base material and depth are included, and how will you handle backfill near the house?
- Will the patio be tied to the foundation or isolated from it?
- How will you get concrete into the backyard and protect the lawn and sprinkler lines?
Ready to plan it? Request a patio contractor and share a photo of the space.
See how it works
Frequently asked questions
Does a concrete patio need HOA approval?
In many Denver-area subdivisions, yes. Communities such as Highlands Ranch require architectural approval for exterior improvements, and many HOAs in Parker, Castle Rock and Aurora have similar rules. Get approval in writing before scheduling the pour.
Should my patio be attached to the foundation?
On expansive soil, many contractors isolate the patio from the house with an isolation joint so the two can move separately. Ask your contractor which approach suits your lot and soil.
When is the best time to pour a patio in Denver?
Mild spring and fall days are easiest on fresh concrete. Summer pours work but need careful timing and curing because of dry air and strong sun, and late fall and winter pours need protection from freezing.
Sources and further reading
- Colorado Geological Survey: expansive soil
- Colorado Geological Survey: heaving bedrock hazards, Douglas County (SP-42)
- CSU Extension PlantTalk: expansive soils
- Jefferson County: geology and dipping bedrock
- City and County of Denver: right-of-way contractor licenses
- Denver DOTI: sidewalk repair and construction
- City of Aurora municipal code: work in the public right-of-way
- City of Lakewood: contractor registration
- City of Arvada: right-of-way permits
- Town of Castle Rock: right-of-way permit information
- Highlands Ranch Community Association: covenants and improvements
- Denver Water: summer watering rules
- Colorado 811: homeowners
- American Concrete Institute (ACI)
- Portland Cement Association (PCA)