Your backyard may look completely still, but the ground underneath it is constantly changing.
In Colorado, seasonal moisture changes, freezing temperatures, snowmelt, and dry periods can cause soil to expand, contract, and shift. You may not notice the movement happening, but over time, your deck, pergola, patio cover, fence, or other outdoor structure can start showing the effects.
And sometimes, the first warning signs are easier to miss than you think.
Here’s how Colorado soil movement works, the signs to watch for, and how a well-built structure handles it.
The Ground Beneath Your Backyard Isn’t Always Stable
Colorado’s soil conditions can be challenging for outdoor construction. Certain soils can expand when they absorb moisture and shrink as they dry out.
Expansive clay soils are common in parts of the metro, and they’re one reason two neighbors on the same street can see very different results from similar decks.
Add Colorado’s freeze-thaw cycles to the equation, and the soil supporting your outdoor structures can experience repeated movement throughout the year.
That movement matters because your deck or patio cover depends on a stable foundation. Even relatively small changes underneath footings or posts can eventually affect how the structure sits.
Small Changes Can Be Warning Signs
Soil movement doesn’t always create an obvious problem overnight. Instead, you might gradually notice things like:
- Deck boards or surfaces that no longer feel level
- Posts that appear slightly tilted
- Stairs that feel different than they used to
- Gaps developing around structural connections
- Pergolas or patio covers that appear uneven
- Fences beginning to lean
- Doors or gates that suddenly become difficult to open
It can be tempting to treat these as cosmetic issues. But when something outdoors begins shifting unexpectedly, it’s worth asking why.
How Colorado Soil Movement Affects Decks, Pergolas and Patio Covers
Each structure shows shifting ground in its own way.
- Decks: An attached deck is tied to a house foundation that moves differently than the footings in the yard. When outer footings rise or settle, the deck slopes and the house connection takes extra stress.
- Pergolas: A freestanding pergola relies entirely on its posts. If one shifts, the frame can rack, and Front Range wind works on any loosened connection.
- Patio covers: A patio cover connects to your roofline on one side and rests on posts on the other. Uneven movement shows up as sagging beams, gaps at the house, or a roof that drains poorly.
Winter adds its own stress on top of shifting soil. We go deeper into that in our article on why decks fail after Colorado winters.
Drainage: The Part of the Problem You Can Control
You can’t change your soil, but you can control how much water reaches it.
- Make sure gutters and downspouts carry water away from the house and away from deck and patio cover footings.
- Check that the ground slopes away from your foundation and outdoor structures, not toward them.
- Watch for spots where snowmelt pools or ice builds up near your deck or patio cover each spring.
Drainage fixes won’t undo past movement, but they can help slow it down.
Why Proper Construction Matters in Colorado
A beautiful backyard structure is only as reliable as the system supporting it.
When building a new deck, pergola, patio cover, or other outdoor addition, contractors need to consider more than appearance. Local soil conditions, drainage, footings, structural loads, materials, and seasonal weather all play a role in how that structure performs over time.
That’s why simply copying a backyard design that works somewhere else isn’t always the best approach for a Colorado home. Footings need to suit the site, and the project needs to meet your city or county’s requirements.
Your outdoor space should be built for where you live. You can see that approach in our gallery of custom decks built for Colorado, our custom pergola projects, and our patio cover gallery.
Don’t Wait Until a Small Shift Becomes a Bigger Problem
If your deck is starting to feel uneven, your pergola looks slightly different than it did last year, or your fence keeps leaning despite previous fixes, the visible problem may only be part of the story.
A professional inspection can help determine whether you’re dealing with normal wear, drainage problems, soil movement, structural deterioration, or a combination of factors.
And if you’re planning a new outdoor project, thinking about these conditions before construction starts is the best protection you have. Planning footings and drainage correctly on day one is far easier than fixing a structure that has already moved.
Frequently Asked Questions
How do I know if Colorado soil movement is affecting my deck?
Look for boards that no longer feel level, leaning posts, or gaps opening at connections. When those changes appear gradually, soil movement or poor drainage is a likely factor, and an inspection can confirm it.
Can a deck that has shifted be repaired, or does it need to be replaced?
It depends on the cause and how far it has gone. Some decks can be corrected by addressing footings, posts or drainage, while others are better replaced.
Does shifting soil affect pergolas and patio covers too?
Yes. Any structure on posts and footings can be affected, and patio covers are especially sensitive because they connect to the house on one side.
When is the best time to check my backyard for soil movement?
Walk around your outdoor structures in spring after the snow melts and again in late fall. Comparing season to season makes slow movement easier to spot.
Build on Solid Ground With CA Carpentry
CA Carpentry is an owner-run carpentry company based in Castle Rock. Chet Anderson started as a framing carpenter in 1995 and still runs the job sites.
If something in your backyard has started to shift, or you’re planning a new project and want it built for local soil and weather, request a free on-site estimate or call 720-628-0173. We usually schedule estimates within one business day.
