| Item | Example input | Example output |
|---|---|---|
| Corner load | 55 kN | Design load ≈ 110 kN (SF 2.0) |
| Soil / depth | Medium sand, competent at 3.5 m | Helical recommended for typical access |
| Settlement | 18 mm | Severity: Significant |
| Helix setup | 0.305 m diameter, 3 helices, eff 0.70 | Capacity estimate depends on soil and torque cap |
| Layout | Wall runs: 4.0 m and 3.0 m | Split piers across both walls with spacing ≥ minimum |
Tip: Enter your pier’s rated allowable capacity to override estimates.
- Design corner load: Pdesign = Pcorner × SF × S, where S is a stiffness factor by structure type.
- Helical bearing-area estimate: Qsoil = qallow × Ahelix × η, where Ahelix = n × π(d/2)².
- Torque correlation cap (optional): Qtorque = Kt × T. The tool uses min(Qsoil, Qtorque) when torque is entered.
- Pier count: N = ceil(Pdesign / Qallow,pier).
- Spacing guidance: smin = max(1.5 m, 3 × dhelix) for helical; a conservative fixed minimum for push piers.
- Embedment target: D = max(Dcompetent, Dfrost + 0.6 m).
- Measure the corner settlement using a consistent reference line.
- Estimate or compute the corner load from tributary areas.
- Enter soil type and any known allowable pressure from reports.
- Provide competent depth or refusal depth if you have it.
- Choose Auto recommend unless your system is fixed.
- If using helicals, enter helix diameter/count and torque if available.
- Enter run lengths along both walls to shape a corner layout.
- Press Calculate recommendation and review spacing and embedment.
- Download CSV or PDF for estimates, quotes, or site notes.
Corner settlement indicators
Track diagonal cracking, sticking doors, and out-of-level floors near the corner. Record the vertical offset at two dates to confirm active movement. A change beyond 3 mm over 30 days suggests ongoing soil or drainage drivers. Photograph reference points and note rainfall, downspout discharge, and excavation activity.
Estimating design corner load
Start with a tributary plan area for the corner and apply dead and live load intensities from your local code or structural takeoff. Convert to a corner reaction and apply the safety factor used in the tool. Stiffer wall systems can shift reactions, so keep assumptions consistent across corners when comparing repair scopes and budgeting.
Helical versus push system selection
Helical support is efficient when access is tight and uplift must be resisted, because capacity can be verified with installation torque records. Push systems are favored when a deep, competent bearing layer is available and extensions can reach refusal. For soft clays or unknown fill, prioritize systems that bypass weak strata rather than spreading load. Confirm headroom, utilities, and slab thickness first.
Pier count, spacing, and embedment
The calculator sizes piers by dividing the design corner load by an allowable per‑pier capacity and rounding up. Distribute piers along both walls so the first pier is near the corner, then maintain spacing that avoids group interaction and fits framing. Embedment should extend below frost and continue to competent material, with extra depth for scour sites.
Verification and construction controls
Before lifting, map utilities, document elevations, and set a target lift plan in small increments. During installation, record depth, torque or termination notes, and bracket locations for each pier. After adjustment, recheck floor elevations and door clearances, then monitor for 60–90 days. If movement continues, investigate drainage, leaks, and nearby grading as root causes. Where possible, include a sketch showing wall runs, pier locations, and measured settlement; it speeds review by installers and supports consistent pricing and permit submittals.
1) How accurate is the recommended pier count?
It is a planning estimate based on your loads, safety factor, and an assumed allowable capacity per pier. Final counts should be confirmed using product data, installation records, and site-specific soil verification.
2) What should I enter if I do not know the corner load?
Use an approximate tributary area for that corner and multiply by realistic dead and live load intensities. If uncertain, apply a conservative safety factor and compare multiple scenarios to bracket the likely range.
3) Why does torque affect helical capacity?
Installation torque is often correlated to axial capacity for helical systems. If you enter torque, the calculator limits the capacity estimate to the torque-based cap to avoid overstating performance.
4) When are push piers preferred?
Push piers are commonly selected when a deep competent bearing layer is present and extensions can reach refusal. They can be effective for severe settlement where shallow soils are weak or variable.
5) How should I use the spacing and layout guidance?
Split piers along both walls from the corner, keeping the first pier close to the corner and maintaining at least the minimum spacing. Adjust for openings, utilities, and framing so brackets land on sound members.
6) Can I export results for proposals or site notes?
Yes. After calculating, use the CSV for spreadsheets and the PDF for printing or sharing. The downloads include key inputs, results, layout steps, and notes for quick reference.