How many helical piles does a deck need compared with a house?

It depends on the weight and length of what's being carried. Cost guides say a small deck may need three piles and a typical house repair five to ten. Minor settlement often takes two to four. The count should come from load calculations and the pier maker's specs, so ask for the pier layout drawn on a plan.

What stops a helical pier at the right depth?

Torque, not a set length. The installer keeps adding shaft sections until the pier reaches the torque that matches the load it has to carry. Most residential piers stop 10 to 30 feet down, though some end at 3 feet and some run past 100. The final torque on each pier belongs in the install log.

Do helical piers work in clay soil?

Yes. Forbes lists sandy soil, dirt and clay as helical pier ground and rock as the poor fit, since a screw plate can't bite into stone. Expansive clay can mean longer, deeper piers than a contractor's standard depth, so get the depth clause in writing. A soil report settles it when nobody knows what's down there.

Helical Piers in Topeka, KS

Per pier: cost guides put a helical pier for foundation repair at $2,000 to $4,000 installed, about $3,000 on most jobs.
Deck and porch piles: about $300 to $500 each, since there's no old footing to dig under.
Time on site: one to four days for most houses once the rig is there.
Depth: most residential piers end up 10 to 30 feet down; past the contract's standard depth, guides list $20 to $35 a foot extra.

Topeka Expert Foundation Repair gets your helical pier job in front of a local contractor who can tell you whether a screwed-in steel pile suits the house, the addition or the deck you have in mind. A helical pier is a galvanized steel shaft with round plates welded near the tip. It's turned into the ground by a hydraulic motor, and a bracket ties it to the footing or beam it has to carry. The call is free, and the quote is between you and the contractor.

Helical Piers for Old Footings, New Additions and Decks

The same steel shaft does three different jobs around Topeka houses. What changes is what it's attached to and how much digging comes first.

Narrow pit dug beside the concrete footing of a brick ranch house, with a galvanized helical pier shaft and a steel retrofit bracket bolted under the footing

Retrofit Helical Piers Under an Existing Footing

This is the repair job: a corner or wall line has settled, and the footing needs something under it that won't move. A pit is dug at each pier spot down to the bottom of the footing. The shaft is screwed in beside it, extension sections are added as it goes down, and a bracket under the footing transfers the house load onto the steel.

Per pier: $2,000 to $4,000 installed, most near $3,000. Forbes splits it as $1,500 to $2,000 for parts and $1,000 to $1,500 for labor.
Tight spots: piers dug by hand because a machine can't reach run $200 to $500 more each.
Things in the way: a deck, patio or landscaping over the pier line may have to come up first, so ask whether putting it back is in the price.

Rows of new helical pile shafts with flat steel caps standing in a cleared clay lot beside an older two-story house, marking out an addition footprint

New Helical Piles for Additions and Garages

On new work there's no old footing to dig beside, which is why cost guides say helical piles cost much less for new construction than for underpinning. The piles go in first and the addition's beam or grade beam sits on their caps. Concrete footings need several days of dry weather to dig and pour; helical piles don't depend on the weather.

Topeka's amended code still expects continuous concrete footings, but it allows other approved engineered systems that carry the loads. So a helical layout for an addition is an engineered design the city has to approve. Footings also have to sit below the city's 36-inch frost line, so the homepage is worth a read on why Topeka soil moves.

Small helical pile with a square steel cap set into sloped clay ground under the corner of a wooden deck frame beside a frame house

Helical Piles for Decks and Porches

Decks and porches are the cheapest helical work: about $300 to $500 a pile installed, and a small deck may only need three. Guides like them on sloped lots where pouring concrete footings would be awkward. A front porch that has dropped away from the house is the same job on a smaller scale. Some piles get an augered hole and a concrete cap, which slows the install a little.

Laser level on a tripod in an unfinished basement, a gloved hand holding a measuring rod and a stair-step crack in the block wall behind

Why Topeka homeowners and property owners call Topeka Expert Foundation Repair

The call and the inspection request cost you nothing
Your details go to one Topeka contractor, never a lead list
Ask for piers, anchors and price on paper before any digging
Method explained first: piers, anchors, straps or mudjacking

Helical Pier Capacity: Ask to See the Torque Log

A helical pier's best feature is that its capacity is measured while it goes in. The International Building Code sets a helical pile's working load from the lowest of several checks: plate bearing on the soil, correlations with installation torque, load tests, and the strength of the shaft, couplings and plates. The evaluation criteria pier makers certify against put the torque rule in one line: ultimate capacity equals a factor (Kt) times the final torque, and the allowable load is half of that.

Kt by shaft
10 for 1.5- and 1.75-inch square shafts, 9 for 2.875-inch round, 8 for 3-inch round, 7 for 3.5-inch round.
Worked example
a 2.875-inch round shaft finishing at 5,000 ft-lb gives 45,000 lb ultimate and 22,500 lb allowable.
Soil report
a geotechnical report runs about $1,000 to $5,000 and sets the depth and torque targets when the soil isn't well known.

So ask for an install log with each pier's final torque and depth. If a pier stopped short of its target torque, you want to know why before the pit is backfilled.

Helical Piers or Push Piers: What Decides It

Helical piers are screwed in rather than pushed down against the house's weight, so they suit porches, additions, decks and lighter loads. Cost guides list rocky soil and very heavy loads as poor fits, and some local codes restrict them. A heavy two-story house on rock-studded ground is push pier territory. Angi's per-pier averages run about $1,000 more for helical than for push piers.

A few quote checks that apply either way:

Depth clause
HomeGuide lists $20 to $25 or more per extra foot and Forbes $25 to $35, so ask for a no-depth-clause price.
Digging and locates
Exterior pits mean utility locates first; the basement wall replacement page has the Kansas 811 rules.
Warranty
Ask whether it transfers to a buyer, and compare it with the norms listed on the homepage.

See foundation piers when the house is heavy enough that push piers driven to rock make more sense.