A 32 inch frost depth and a county soils map decide what goes into the ground at a Durango site long before anyone sketches the walls. La Plata County design criteria list a 32 inch frost depth, Seismic Design Category B, a 115 mph ultimate wind speed, Climate Zone 5 and 6,981 heating degree days, plus a roof snow load taken from Table 301.2(2). We carry those numbers into the structural drawings and the mechanical load calculations from the first sketch, because a shop or plant that is designed to a generic set of loads will not match what the plan reviewer expects.
The county also requires a soils report, an engineered foundation design or both where its GIS mapping shows expansive clay, and its minimum foundation details cannot be used in expansive soils without an engineer stamp. That rule matches how we work anyway. For industrial owners, we build drilled pier foundations, grade beams, structural slabs and equipment pads that are designed from the geotechnical report, not from a default footing, and we coordinate the report, the stamp and the permit submittal as one package.
Jurisdiction is the second item to settle. The county enforces the 2015 International Building, Residential, Mechanical, Plumbing, Fuel Gas and Energy Conservation codes in unincorporated areas, according to a permit packet revised February 9, 2024, while the City of Durango, the Town of Ignacio and the City of Bayfield sit outside that county jurisdiction. We confirm which office reviews your parcel before we price.
Reading the county criteria into the drawings
The design table is only useful if it is applied across disciplines. Frost depth sets footing and utility trench depth. The 115 mph wind speed sets cladding attachment, door and canopy bracing and the uplift on roof connections. Seismic Design Category B sets the lateral system detailing and connection requirements for a pre-engineered or steel frame. Heating degree days and Climate Zone 5 set insulation values and the heating plant size for a conditioned production space.
We put those values on a single design-criteria sheet at the front of the drawing set and hold each subcontractor to it. When the permit packet and the jurisdiction differ, or when the packet is revised, we document the version used and the date. That record helps when an inspector asks why a footing is 32 inches and not 36.
Piers, slabs and pads we manage closely
Where the report calls for deep foundations, we drill piers to the specified depth and bearing stratum, inspect the bottom, place the cage and pour the same day so the hole does not stand open. Deep foundations and piers are paired with grade beams that bridge over swelling soils, with void forms or compressible material beneath them where the engineer requires it.
Industrial floors are the next item. We place industrial concrete floors that are isolated from the walls and columns when the soils can move, with joint layouts chosen for the traffic and the equipment, and sealed or cured to the owner's requirements. Equipment pads for compressors, generators and process equipment are cast with embedded bolts set from the vendor drawings.
Water and clay on the same lot
Expansive clay becomes a problem when it wets and dries. Roof water that discharges at the footing, a downspout that ends at a wall or a landscaped bed against the foundation can move a slab. We design the site so water leaves the building quickly: positive slope away from the structure, gutters or scuppers tied to a conveyance, and an apron of non-expansive fill in the first several feet around the perimeter.
Utilities are also part of the picture. A sewer or water line that settles because the trench backfill was not compacted can break a floor from beneath, so we specify bedding, compaction testing and flexible connections where lines enter the building. When we scope stormwater detention and drainage, we keep detention basins away from the foundation and out of the swell zone.
Building near an airport that cannot close for long
Durango-La Plata County Airport handled 563,009 passengers in 2025, its busiest year on record and up 13% from 2024, with United carrying 57% and American 43%. The airport's terminal program ran Phase 1A construction from April 2023 to July 2024, and Phase 1B construction began in October 2024 on a 27 month schedule. In summer 2022 the airport closed for 10 full days to reconstruct the entire length of its 9,200 foot runway, which is its only runway.
Those numbers describe how tight airfield windows are. For apron concrete, hangar pads, ground support equipment buildings and utility crossings in an active airfield, we plan work in short, fully-resourced closures: material staged, crews committed, curing and joint sawing scheduled, and a fallback ready if weather moves the pour. We also coordinate haul routes and escorts with airport operations so construction traffic stays off movement areas.
Shops, hangar-adjacent buildings and yards
Beyond the airport, we build maintenance shops, fleet buildings and yards for the services that support the area. A typical package combines a hangar-style clear-span building or a service shop with a concrete apron and a fenced yard. Door size, structure and fire protection come from the equipment that will enter the building.
Owners who run mixed fleets also use our maintenance shop and service bay design: drive-through lanes, floor drains with oil separation where required and slab details that accept a lift. Neighboring markets such as Telluride and Montrose share the supply routes we use, and light assembly and advanced manufacturing users in the county can use the same foundation and floor package.
Send the parcel and the soils report
If you have a geotechnical report, send it with the plat and the equipment list. If not, we will help you scope one. We will return a foundation concept, a permit path and a priced scope.
Common Questions
Do I need a soils report for a new industrial building in La Plata County?
In unincorporated areas the county requires a soils report, an engineered foundation design or both where its GIS mapping shows expansive clay, and the minimum foundation details cannot be used in expansive soils without an engineer's stamp. Even outside the mapped areas, we recommend a geotechnical report for any building with heavy floor loads or process equipment.
Which office reviews my permit, the county or the city?
It depends on where the parcel sits. The county enforces its adopted codes in unincorporated areas, and the City of Durango, the Town of Ignacio and the City of Bayfield are outside that county jurisdiction. We confirm the reviewing office, the edition and the submittal list before pricing.
How do you schedule concrete work on an airfield with one runway?
We schedule pours inside the closure window the airport grants, stage all material beforehand and plan cure time and joint sawing so the surface is ready when the airport reopens. The 10 day runway reconstruction in summer 2022 shows how little slack there is, so we also keep a weather fallback.
How do 6,981 heating degree days affect the building design?
They drive insulation levels, the heating plant size and freeze protection for piping and wet systems. For a production space we calculate the heating load from the actual process and the door-opening pattern, not from a default.
Can I use a pre-engineered metal building on expansive clay?
Yes. The frame is light, and the foundation is designed to resist movement. Pier-and-grade-beam foundations or a structural slab are common, and the metal building manufacturer's anchor bolt reactions go to the foundation engineer for design.