Arvada Footings and Piers

Third week of August, no measurable rain in a month, and the lawn crunches. Walk to the back of the yard and the clay has opened up in seams you could lose a pencil in. This is the week the phone starts. A deck corner that was fine at Memorial Day now sits low enough that the gate scrapes. A porch column has a daylight gap under its base plate. Nothing dramatic happened. The ground just got dry, shrank, and took the shallow stuff down with it.

It's also the easiest drilling of the year, and that's the trap. An auger cruises through dry ground and comes out clean, which makes a hole feel deeper and better than it is. We set depth off what the load and the freeze line demand, not off how nice the digging is on the day we happen to be there.

The dry-down, and what it takes with it

Shallow supports ride the top layer of soil, and the top layer is the part that changes the most. It swells after a wet spring, gives that volume back through a rainless summer, and freezes with whatever water is still in it come January. A house on real footings sits out all of that. A deck post on a block, a shed corner on a paver, a pergola foot cast twelve inches deep: those go along for the whole ride.

Around Olde Town we mostly see it on porches, stoops, and detached garages that were built when nobody thought a support needed a design. West Woods brings decks on sloping back yards where the downhill posts carry the most and sit in the loosest ground. And out in Candelas, Leyden Rock, and Whisper Creek the calls come faster than people expect on brand-new houses, because a post set in the backfill against a foundation is standing in dirt that's still packing itself down.

Depth is what makes the season irrelevant

Every seasonal symptom on this page has the same answer, and it's boring: get below the layer that moves and stay there. Below the freeze line so ice can't lift it, past disturbed fill so consolidation can't drop it, into material that has the bearing the load needs. Diameter answers the load. Depth answers the weather. People try to trade one for the other and it never works, because a wide shallow pad is just a bigger thing for the frost to push on.

Then we cut the ground's grip on the shaft. A smooth-sided pier gives expanding soil nothing to grab, steel ties the top of the pier to what it carries so uplift has to fight the whole assembly, and where the design calls for it a void under the load keeps swelling soil from pressing directly on concrete. That combination is why a properly built pier does the same thing in February that it did in August.

When the movement shows up, and what that timing means

Drilling through an Arvada year

September through November is our favorite stretch. Ground is dry, holes stand open without sloughing, and the yard recovers before you're using it again. Late spring is the hardest: saturated clay smears on the auger, holes want to collapse, and a rig leaves ruts in a lawn that hasn't dried out from snowmelt yet.

Winter work happens and it happens more often than people think. The top foot or so is frozen, which the auger handles, and everything below it is workable. What we won't do is place concrete against frozen material at the bearing surface, so holes get drilled and poured the same day, spoils get pulled back from the edge, and cold-weather mix and protection come standard from November on. If a deck is unsafe in January, it doesn't get to wait for April.