The underpinning process: what happens, in what order

The sequence, step by step

A properly run underpinning job follows the same order every time, whichever method ends up under your footings.

• Engineer's assessment and design. A structural engineer diagnoses the movement, orders a soil test, and designs the fix — which walls, which method, what depths. This is the document everything else hangs off; see engineer's reports for what it covers and costs.
• Fix the cause. If a leaking pipe or failed drainage moved the soil, it gets repaired first. Underpinning over an active leak is paying twice.
• Approvals where required. Depending on your state and the scope of work, a building permit or approval may be needed before work starts — the regulations guide covers each state.
• Staged works. The contractor executes the engineer's design: pins in sequence, piles to torque, or resin to measured lift, depending on the method.
• Inspections at hold points. The engineer inspects at defined stages — excavations open, piles at depth, before load transfer — not just at the end.
• Certification and warranty documents. The job finishes on paper: certification that the work matches the design, plus warranties and final invoices.

Timeframes by method

On-site time varies enormously by method, which is worth knowing before you compare quotes. Resin injection is measured in days, and often a single one. Screw piles typically take one to two weeks on site, with the piles themselves going in quickly and the brackets and load transfer taking the balance. Mass concrete runs two to four weeks for a typical residential job, because each pin must cure before its neighbour is dug — the concrete sets the pace, not the crew.

Add lead time before anyone lifts a shovel: the engineer's report, soil test, contractor quotes and any approvals commonly take several weeks together, and an engineer may sensibly want to monitor cracks for a season before committing you to work at all. If someone is pushing you to skip straight to construction, that urgency serves their schedule, not your house — do I need underpinning? covers when waiting is the right move.

Living through the works

You almost never need to move out. Mass concrete means open trenches along the affected wall, fenced off and off-limits to kids and pets, with hand-digging noise through working hours. Screw piles bring short bursts of machinery noise and a few small pits. Resin crews are typically in and out within a day, working from inside or beside the house with gear that fits through the front door. Expect one side of the house to be a work zone for the duration, and ask the contractor at quote stage what access they need and what gets reinstated afterwards.

The paperwork to keep

The job is not finished when the crew leaves; it is finished when you hold the documents. Keep the engineer's design drawings and final inspection or completion certificate, any permit and certification paperwork, torque or lift records where the method produces them, the written warranty, and the itemised invoice. This file matters twice over: it supports any future insurance conversation, and it is what a buyer's conveyancer will ask for when you sell. Underpinning with certification reads as a fixed problem; underpinning without paperwork reads as a mystery.

Crack repair comes after — and separately

Underpinning stabilises the footings; it does not re-point brickwork, patch plaster or repaint. Some methods recover a little height and cracks may partially close, but cosmetic repair is a separate trade and usually a separate bill.