A foundation is only as good as the ground under it and the water around it. We don't pour concrete. We do the excavation and earthwork that gets a foundation ready, then come back to backfill and grade once the concrete crew is done.
Foundation Groundwork in Boise
People call us asking about foundations, and the first thing we tell them is what we do and don't do. We aren't a concrete company. We dig, prep the soil, set the base, handle the drainage and backfill. Your concrete contractor forms and pours. Splitting it that way works well, because each crew does the part it's set up for.
We do foundation groundwork in Boise, Meridian, Nampa, Star, Middleton and Eagle, for homeowners, builders and people putting up a shop on acreage.
Crawlspace, Slab or Basement
The type of foundation changes what the ground needs. Your designer or engineer picks the type, usually based on the lot, the soil and the budget. Our job is to prep the ground for whichever one is on the plans, and each of the three common types around the valley puts the weight and the water in different places.
Crawlspace
Crawlspaces are very common on newer homes around the valley. Perimeter footings and stem walls carry the house, with a shallow open space underneath. The groundwork is a perimeter dig below frost, interior pads for piers, and a crawlspace floor graded so water doesn't pool under the house.
Slab on grade
Garages, shops, ADUs and a lot of single-story homes sit on a slab. Here the base under the whole footprint matters as much as the edges. We cover that prep on our slab excavation page.
Basement
Basements need the deepest dig, the most spoil handling and the most attention to groundwater. Before choosing one, it's worth knowing how high the water gets on your lot during irrigation season and whether caliche or basalt sits within a few feet of the surface. See basement excavation.
What the Soil Can Carry
Every footing is sized for the soil it sits on. Good native soil, tight gravel or caliche can carry a lot. Soft clay, loose sand and old fill can't carry as much, and they can settle unevenly.
On many new homes, a geotechnical engineer does a soils report and lists the bearing capacity and any special prep. If the report says to remove soft soil and replace it with compacted structural fill, we dig it out, bring in the fill and compact it in lifts. Our compaction page explains why lifts matter. If there's no soils report and we find something that worries us, we'll tell you before anything gets formed.
Without a report, the dig itself tells us a lot. Dark, spongy soil full of roots is organic material that has to come out. Brick, concrete chunks or trash in the walls of the trench point to old fill. Gray, wet soil that smells sour can mean poor drainage or high water. Hard white caliche at footing depth usually carries weight well, even though it's slow to dig.
Clay is worth a special mention. Parts of the valley have clay that swells when wet and shrinks as it dries. Keeping water away from it, and not building on it while it's saturated, goes a long way.
Additions and Shops
Home additions
An addition has to tie into a house that's already there. The new footing usually has to match the depth of the old one, and we have to dig next to the existing foundation without undermining it. That means careful work along the wall, often by hand at the tie-in, and watching for sprinkler lines, gas and power coming into the house. Before we start, we find out where the existing footing is and how deep it goes, often by hand digging a small test spot at the corner where the two will meet.
Shops and pole barns
Shops on acreage around Star, Kuna, Middleton and Parma are often post-frame buildings. The posts go in holes, and the floor comes later. We can drill the post holes with augering, level the pad and prep the floor base so the building and the slab end up at the same height.
Drainage Around the Foundation
Water does more damage to Treasure Valley foundations than anything else. Irrigation runs all summer, roughly April through October, and spring rain and snowmelt soak clay soils that don't drain well. Wet soil against a wall pushes on it, and wet soil under a footing softens and can settle. Most of the fixes are cheap to build in during groundwork and expensive to add once the house is finished and landscaped.
- Footing drains at the base of the footing carry water away when the plans or the site call for them.
- Gravel and fabric around the drain keep it from clogging with silt.
- Downspouts should discharge well away from the house, not at the foundation.
- Final grade should fall at least 6 inches in the first 10 feet away from the house.
For drainage problems around an existing home, like a damp crawlspace or water standing against the foundation, see drainage excavation. Fixing the grade and extending downspouts is often the first step. A drain or deeper regrading comes next if that isn't enough.
Getting the Site Ready for the Concrete Crew
When the concrete crew arrives, they need clean footing trenches at the right depth, a pad that's level and compacted, and room to get a truck or pump close. We clear a path, keep spoil out of the way and coordinate with your plumber if lines have to go under the slab before the base goes in. After the walls cure and pass inspection, we backfill and rough grade. The dirt goes back in layers, with big rocks kept off the walls and any footing drain, and the final grade gets shaped to fall away from the house. See backfilling.
Why Hire Ultimate Excavation LLC
We're an Idaho registered contractor (RCE-65836) based in Caldwell, with a 5.0 rating on Google. One reviewer called us "knowledgable, respectful and budget friendly" and "great for earthwork services on your projects." That's the part of a foundation we handle. Call (208) 697-2429 or request a free estimate.
