Retention in construction: what it is, and how to stop it dragging

Retention is the slice of your money the client holds back on every payment, usually 5%, and hangs onto until well after the job is done. On a £40,000 job that is £2,000 sitting in someone else's account. Money you have earned, that you cannot use.

What retention actually is

Retention is a small part of each payment the client keeps back to make sure you come back and fix any defects. It is not a penalty and it is not the client's money to keep. It is yours, held as security, and it should be released to you on agreed dates.

The problem is not the idea. The problem is how often it is left vague, so the release date slips, the client goes quiet, and you end up chasing a sum that was yours all along.

How retention works: the two releases

Retention is normally released in two parts. The first half is released at practical completion, when the work is finished and the client can use the space. The second half is released at the end of the defects liability period, also called the rectification period: a window after completion, often six or twelve months, during which you put right anything that shows up. Once it ends and any snags are fixed, the balance is due.

Two releases, two dates. If both dates are written into the contract, retention is manageable. If they are not, it drifts.

How much retention is normal

In UK construction, retention is usually 3% to 5% of the contract value. A common structure is 5% held during the works, halved to 2.5% at practical completion, with the final 2.5% released at the end of the defects period. The defects period is typically 6 to 12 months. Longer than twelve months is unusual for standard renovation work, and worth pushing back on.

Retention on domestic renovation jobs

Formal retention is mostly a commercial construction practice, written into JCT and NEC contracts on large projects and subcontracts. On a domestic renovation, a homeowner hiring a builder for a kitchen or an extension, you will rarely see a formal retention clause. The same instinct still shows up though: a homeowner may want to hold back a final slice until snagging is done and they are happy with the work.

That is reasonable, and it does not have to cost you. Make it explicit rather than open-ended. Agree a small final payment tied to a clear sign-off and a date, not to "when I get round to checking." Better still, structure the whole job as stage payments, so the homeowner feels secure at every step and you are paid as you go rather than months after the job ends.

Why retention hurts your cash flow

Retention quietly floats your client's risk on your money. You have paid for the materials and the labour. You have finished the work. And a chunk of your margin still sits unpaid, sometimes for a year, while you fund the next job out of your own pocket. Stack that across three or four jobs and the numbers get real. It is one of the biggest hidden drains on a contractor's cash flow, precisely because it feels normal.

How to stop retention dragging

For the wording that makes this stick, see our guide to the agreements that protect your cash flow.

The cleaner alternative: get paid as you go

Retention exists because payment is not guaranteed, so clients hold money back as leverage. Change how the payment works, and you change the need to leave money hanging.

With Renno, the project budget is funded up front and held safely before you start. You finish a stage, the client confirms, and the payment is released to your account instantly. There is no large sum sitting in limbo for a year, because you are paid for each stage as you complete it. You still stand behind your work. You just stop financing your client while you do. See how Renno works for contractors.

Related guides

• Staged payments for contractors: a complete guide
• How to price a renovation job: the three costs you miss

This article is general guidance, not legal or financial advice. Retention terms vary by contract, so always check what you have agreed.