Breaking ground on a new home, addition, or outbuilding is one of the most significant investments a property owner makes. And in Colorado Springs, the excavation phase of that project comes with challenges that don’t exist in most other parts of the country.
The combination of expansive clay soil, caliche hardpan, a deep frost line, and significant elevation means foundation excavation here requires more planning, the right equipment, and an excavator who understands local conditions. At KDM Earthworks, foundation excavation is one of our core services — and this guide covers everything you need to know before you break ground.
Why Foundation Excavation in Colorado Springs Is Unique
The 36-Inch Frost Line
Colorado Springs sits at roughly 6,000 feet elevation, and the ground freezes deep. The frost line — the depth to which soil freezes in winter — is 36 inches in El Paso County. This is the minimum depth any foundation footing must be set to avoid frost heave, which is the destructive upward movement that happens when frozen soil expands beneath a structure.
A footing set above the frost line will move. Over time, that movement cracks foundations, shifts walls, and causes settling damage throughout a structure. Every foundation we excavate is dug to meet or exceed the 36-inch requirement, with additional depth for the foundation wall and any required drainage.
Expansive Clay Soil
El Paso County soil is heavily clay-based. Clay expands significantly when it absorbs moisture and contracts when it dries — sometimes shifting by several inches over a single season. This movement is called differential settlement, and it’s one of the leading causes of foundation cracking in Colorado Springs homes.
The solution isn’t just digging deeper — it’s also about how backfill is selected and placed after the foundation is formed. Proper foundation excavation includes overexcavating in some areas, removing expansive soil, and backfilling with engineered material that doesn’t shift the same way. We account for this in our excavation scope, not as an afterthought.
Caliche Hardpan
Caliche is a calcium carbonate layer that forms at varying depths across El Paso County — sometimes a few inches down, sometimes several feet. It’s extremely hard, often requiring rock-breaking equipment to penetrate. For foundation excavation, hitting a caliche layer can significantly change the difficulty and timeline of a project.
We assess caliche risk before we start and carry the tooling to break through it when needed. A contractor who hasn’t encountered caliche before — or doesn’t have the right equipment for it — can find themselves stopped cold on what looked like a straightforward dig.
Rocky Terrain and Granite
In parts of Colorado Springs — particularly the west side, Manitou Springs, and higher-elevation areas — bedrock can be surprisingly close to the surface. Foundation excavation in these areas may require rock breaking or blasting, which changes the scope considerably. We identify bedrock risk during site assessment so there are no surprises mid-project.
What Foundation Excavation Actually Involves
Foundation excavation isn’t just digging a hole. Here’s the full sequence of what a properly executed foundation dig looks like:
1. Site Assessment and Layout
Before a single bucket of dirt moves, we walk the site with you and your builder to confirm the foundation footprint, identify utility locations, assess soil conditions, and plan spoil (excavated material) staging. Access for equipment and concrete trucks is also mapped at this stage — something that’s easy to overlook on narrow lots or properties with limited road access.
2. Stripping and Topsoil Removal
The top layer of organic soil is stripped and stockpiled separately. This material can often be reused for finish grading around the foundation once construction is complete, which reduces the need to import topsoil. We don’t mix topsoil into the excavated material — it needs to stay separate to be reused properly.
3. Main Excavation
The primary dig removes soil to the required depth for your foundation type. A crawl space foundation typically requires 3-4 feet of depth below grade. A full basement goes deeper — often 8-10 feet below finish grade, which means the actual excavation depth from existing ground level is deeper still depending on the site’s slope and elevation changes.
We work to your engineer’s specifications and the building permit requirements. If soil conditions change mid-dig — unexpected rock, loose fill from a previous structure, or a caliche layer at an unexpected depth — we communicate that immediately rather than digging through and hoping for the best.
4. Footing Trenches
After the main excavation, we cut footing trenches at the perimeter and any interior load-bearing points. These trenches are dug to the exact dimensions your engineer specifies — width and depth matter for structural reasons, and they need to be clean and level so concrete forms sit properly. Sloppy footing trenches create headaches for the concrete crew and can affect the structural integrity of the pour.
5. Drainage Prep
Proper foundation drainage is non-negotiable in Colorado Springs clay soil. We prepare the grade inside the excavation for interior drain tile, and we cut exterior drainage channels where specified. Some foundation systems also require a gravel layer below the slab — we coordinate with your builder on what’s needed.
6. Spoil Management
Excavated material has to go somewhere. On most foundation projects, a significant portion of the spoil is reused for backfill after the foundation walls are complete. The rest may be spread on-site for grading or hauled off, depending on what the project requires. We stage spoil thoughtfully so it doesn’t interfere with construction access and can be efficiently moved in the next phase.
Foundation Types and How Excavation Differs for Each
Full Basement
The most excavation-intensive option. Full basements in Colorado Springs typically require 8-10 feet of depth from finish floor to the underside of the first floor, plus the depth of the footing itself. On a sloped lot, one side of the excavation may be dramatically shallower than the other. Shoring or sloped walls may be required depending on soil stability and proximity to property lines.
Crawl Space
A crawl space foundation requires less depth — typically 3-4 feet below grade — but still must clear the frost line at the footing level. Crawl spaces are common in Colorado Springs and are sometimes preferred on lots with shallow bedrock or where a full basement isn’t practical. Drainage and vapor barrier prep inside the crawl space is important given local moisture conditions.
Slab on Grade
Slab foundations require the least excavation depth but still need frost-protected footings around the perimeter. In Colorado’s climate, a standard slab on grade requires either deep perimeter footings or a frost-protected shallow foundation (FPSF) design with insulation. The excavation scope for a slab is primarily stripping, perimeter footing trenches, and prep for the gravel base layer under the slab.
Addition or Garage Foundations
Adding to an existing structure requires careful excavation to avoid disturbing the existing foundation. We work methodically around existing footings, often hand-digging close to existing concrete before bringing equipment in. The tie-in point between old and new foundation is critical — proper excavation sets that up correctly.
How Long Does Foundation Excavation Take in Colorado Springs?
Most residential foundation excavations take one to three days, depending on size, soil conditions, and access. A standard single-family home footprint on relatively accessible soil with no major caliche can often be completed in a day. Larger footprints, rocky conditions, or limited access add time.
Weather is a factor. Extended rain or snow can make the excavation area difficult to work in and can affect the stability of open cut walls. We factor seasonal timing into project planning — late spring and early fall are often ideal windows in Colorado Springs.
Do You Need a Permit for Foundation Excavation in Colorado Springs?
Yes — any new foundation for a habitable structure requires a building permit from the City of Colorado Springs or El Paso County, depending on your location. The excavation itself is typically covered under the building permit, not a separate permit. Utility locates (call 811 before you dig) are required before any excavation starts regardless of permit status.
If you’re working with a general contractor, they typically pull the permit. If you’re an owner-builder, the permit is your responsibility. We can dig to the permitted plan once it’s in hand.
Why the Excavation Phase Sets Up Everything That Follows
A foundation is only as good as what it sits on and how it was installed. Excavation quality affects:
- Footing depth and frost protection — too shallow and you’ll see movement
- Soil bearing capacity — excavating into disturbed or organic material leads to settling
- Drainage performance — poorly graded excavations hold water against foundation walls
- Concrete crew efficiency — a clean, accurate dig means forms go in faster and pour smoother
- Backfill performance — what you pull out determines what goes back in and how well it drains
Getting this phase right isn’t just about digging a hole. It’s about setting up every trade that comes after you.
Frequently Asked Questions About Foundation Excavation
Q: How deep does a foundation need to be in Colorado Springs?
A: Footings must extend below the 36-inch frost line in El Paso County. This means the bottom of the footing must be at least 36 inches below the finished exterior grade. Depending on your foundation type — slab, crawl space, or full basement — the total excavation depth will be greater than this minimum.
Q: How much does foundation excavation cost in Colorado Springs?
A: Foundation excavation cost depends on the footprint size, depth required, soil conditions (especially caliche), access limitations, and spoil disposal needs. Every project is different enough that we price after a site assessment rather than quoting per square foot. Call us for a free estimate — Kalten walks every job before we price it.
Q: What happens if you hit rock during foundation excavation?
A: Rock or dense caliche mid-excavation is not uncommon in Colorado Springs. Depending on depth and hardness, we use hydraulic breakers or jackhammer attachments to break through. If bedrock is encountered at a depth that changes the foundation design, we coordinate with your engineer and builder to confirm the right path forward before proceeding.
Q: Can you excavate near an existing structure?
A: Yes, with care. Excavating close to an existing foundation requires assessing the existing structure’s footing depth, the soil type, and the distance from the cut to the existing concrete. We work methodically in these situations — often hand-digging close to existing footings and using smaller equipment to minimize vibration and soil disturbance.
Q: How do I prepare my site before excavation starts?
A: The most important step is calling 811 to have utilities marked — this is required by law before any excavation. Beyond that, clear access for equipment (typically a mini excavator or full excavator depending on scope), confirm your permit is in hand if required, and make sure your builder has staked the foundation corners. We’ll take care of the rest.
Q: Does KDM Earthworks handle the full excavation process or just the digging?
A: We handle the full excavation scope — site assessment, stripping, main dig, footing trenches, drainage prep, and spoil management. We work directly with your builder or general contractor to make sure the excavation sets up the foundation phase correctly. Call (970) 765-1862 to discuss your project.