Snagging & Handover: Your Final Check Before Payment

You’ve lived through the dust, the noise, the missed delivery slots and the weekly site meetings. Your renovation or extension is almost complete. The builder says the job is done and the final invoice is sitting in your inbox.

This is the moment most homeowners get wrong.

Signing off too quickly — or paying that final invoice before a thorough snagging inspection — is one of the most common and costly mistakes in residential construction. Once money changes hands and the contractor’s van pulls away, your leverage disappears almost entirely.

This guide walks you through exactly how to approach snagging: what to inspect, how to document defects, what retention clauses actually do, and how to enforce remedial work if your builder pushes back. Whether you’re managing a loft conversion, a full-house renovation or a rear extension, the principles are the same.

What Is Snagging? (And What It Isn’t)

Snagging is the process of identifying defects, incomplete items and substandard workmanship before you make your final payment and formally accept the completed project.

A snag is any item that:

Doesn’t meet the agreed specification or drawings
Represents substandard workmanship relative to industry standards
Is unfinished, damaged or incorrectly installed
Fails to function as intended

Snagging is not a wish-list for changes you’ve decided you want after the fact. It’s also not an excuse to delay reasonable final payment indefinitely. The distinction matters — legitimate snags are the builder’s responsibility to rectify at no extra cost. Post-contract changes are a separate conversation.

When Should Snagging Happen? Timing Your Inspection Right

The snagging inspection should take place after the builder declares practical completion — meaning all major works are done — but before you make the final payment.

A few practical points on timing:

Don’t rush it. Ask for at least 48–72 hours between being notified that the work is complete and conducting your inspection. You need time to go through the property properly.
Inspect in daylight. Natural light reveals uneven paint, poor grouting and surface defects that artificial lighting can hide.
Bring someone with you. A second pair of eyes catches things you’ll miss, especially if you’re emotionally invested in the project.
Don’t inspect while trades are still on site. If work is genuinely ongoing, the project isn’t at practical completion yet. Politely say so.

A note on new builds vs. renovations: On new-build projects, developers are often incentivised to declare completion before the property is truly ready. On renovation projects, the same pressure exists — a contractor who has moved their team on to the next job will push for sign-off. Hold your ground.

How to Conduct Your Snagging Inspection: A Room-by-Room Framework

Approach your inspection methodically. Work through the property room by room, top to bottom (starting at roof level or the top floor and working down). Within each room, work around the perimeter before moving to the centre.

Bring with you:

A snagging checklist (see the categories below)
A notepad or a snagging app on your phone
A phone or camera for photographs
A torch for dark corners, under-stairs cupboards and loft hatches
A spirit level (a long one if possible)
A plug-in socket tester (available for under £10 from any hardware shop)
A marble or a pound coin — roll it across floor surfaces to test for level

For each defect you find, note: the location, the nature of the defect, and your photographic evidence. We’ll cover documentation in detail shortly.

The Most Common Defects to Look For

Finishes and Decorating

Painting and plastering defects are the most numerous items on any snagging list. They’re also the ones contractors are most likely to dismiss as trivial — which is why it pays to be precise.

What to check:

Uneven paint coverage, visible brushstrokes or roller marks
Paint splashes on skirting boards, floors, glazing or ironmongery
Cracks in plaster — hairline cracks at junctions are expected as the building settles, but wider cracks or cracks across open plaster faces are not
Poorly finished or inconsistent skim coat (run your hand across the wall)
Gaps between the top of skirting boards and the plaster wall
Grout lines that are uneven, cracked, incomplete or inconsistently coloured
Tile lippage — where adjacent tiles are not flush with each other
Exposed fixings, raw edges or unfinished beads around plasterboard joints

Joinery and Carpentry

Doors that don’t close cleanly, rub on frames, or have visible gaps around them
Kitchen and fitted furniture that isn’t level or plumb
Handles, hinges and latches that are misaligned or loose
Skirting and architrave that hasn’t been properly mitred at corners
Staircase balustrades — check they are rigid and meet building regulations (balusters must be spaced so a 100mm sphere cannot pass between them)
Worktops that aren’t properly supported, have visible seams, or have gaps at the wall

Electrics and Lighting

Important: You are not conducting an electrical inspection — that must be carried out by a qualified electrician who issues an Electrical Installation Completion Certificate (part of the required documentation at handover). What you’re checking here are operational and cosmetic issues.

Test every socket with your socket tester
Switch every light on and off — check for flickering, non-functioning fittings or missing covers
Check that switch and socket plates are level and flush to the wall
Look for unfinished trunking, exposed cables or conduit that was supposed to be concealed
Confirm that any extractor fans are working and that their timer functions correctly
Check that the consumer unit (fuse board) is labelled clearly

Plumbing and Heating

Run every tap — check for adequate flow, that hot water arrives within a reasonable time, and that mixer taps and thermostatic controls work correctly
Flush every toilet and check cisterns refill fully
Run showers and check for leaks at the tray seal and around the enclosure
Check under-sink pipework for drips or poorly made connections
Check radiators heat up evenly (cold spots at the top suggest trapped air — the system should have been balanced and bled)
Look for visible silicone bead that has been poorly applied, cracked or gone mouldy already (a sign of old silicone that wasn’t fully removed before re-application)
Check that any underfloor heating zones are functional using the thermostat
Confirm that all relevant pressure test certificates and gas certificates have been provided

Windows, Doors and External Works

Open, close and lock every window and external door — they should operate without force
Check that trickle vents are present and functional where required
Inspect the external threshold detail — water should drain away from the building, not towards it
Check pointing on brickwork for consistency and completeness
Look at any new render for cracking, staining or patches that haven’t been finished to a consistent texture
Inspect drainage gullies and downpipes — are they connected and free of debris?
If a terrace or garden area was included in the scope, check falls on paving (water should run away from the building) and that steps are level and stable

Structural and Waterproofing Items

These are the high-stakes items. Most are invisible once the building is finished, which is why the paper trail (building control sign-off, structural engineer’s sign-off, warranties) matters as much as the physical inspection.

Check that a Building Regulations Completion Certificate has been applied for and received
If structural steel was installed, confirm that the engineer’s inspection notes are available
For extensions and loft conversions, check the junction between old and new fabric — look for signs of water ingress, gaps in the upstand detail at rooflights, or poorly finished lead flashing
In basements or below-ground spaces, check for any dampness, efflorescence (white salt deposits on walls) or standing water
If a flat roof was installed, confirm that the installer has provided a manufacturer-backed warranty

How to Document Defects Properly

Verbal snagging lists are next to useless. Your documentation needs to be clear, specific and timestamped.

The right format:

Photograph every defect — close-up and wide-angle — so the location in the room and the nature of the defect are both visible.
Write a numbered snagging list in a document or spreadsheet. Each entry should include: item number, room/location, description of defect, photo reference.
Send it in writing — email is fine — to your contractor. Ask them to confirm receipt and to provide a programme for remedial works within a set timeframe (5–10 working days is reasonable).
Keep a record of all replies. If the contractor says something verbally, follow it up in an email: “Further to our conversation today, I understand you’ll address items 3, 7 and 12 by [date]. Please confirm.”

Avoid apps or platforms that only your contractor controls — you need your own independent copy of everything.

Understanding Retention Clauses: Your Financial Lever

A retention clause allows you to withhold a percentage of the contract sum until defects have been rectified. It is the single most effective financial protection available to you.

How it typically works:

A retention of 3–5% of the contract value is withheld at practical completion
This is released after a defects liability period — usually 6–12 months — during which the contractor is obliged to rectify any defects that emerge
A second, smaller retention (sometimes half the original sum) may be withheld until the end of the defects period

If your contract doesn’t include a retention clause:

You can still negotiate one before the project starts — this is far easier to do at the outset than partway through
On smaller domestic projects where a formal JCT contract isn’t in place, it’s reasonable to agree in writing that the final payment (typically 5–10%) will only be released once all snagging items are resolved to your satisfaction

Important: A contractor who flatly refuses any retention or final-payment-holdback mechanism is a significant warning sign. Reputable contractors with confidence in their work don’t object to reasonable retention terms.

What if no retention was agreed?

You still have options. Under UK consumer law, if you commissioned work as a residential consumer, the contractor has an implied obligation to carry out the work with reasonable care and skill (Consumer Rights Act 2015). Defective work can be pursued as a breach of contract even after payment — though it becomes more complicated and costly. The lesson: agree retention terms before work starts.

Dispute Resolution: What to Do When a Builder Pushes Back

Not all disputes are bad faith — sometimes there is genuine disagreement about whether something constitutes a defect or falls within the agreed specification. Here’s how to handle pushback professionally.

Step 1: Refer Back to the Contract and Specification

Every snagging dispute should be resolved against the agreed scope of works and specification. If the contract says “paint all walls with two coats of trade emulsion,” and the coverage is visibly thin, that’s a contractual issue — not a matter of opinion.

Step 2: Get an Independent Assessment

If you and your contractor genuinely disagree about whether something represents a defect, commission a brief report from an independent building surveyor or clerk of works. This costs money (typically £300–£600 for a focused inspection report) but provides an authoritative, impartial opinion that is difficult to dismiss.

Step 3: Use Formal Dispute Resolution Mechanisms

If your contract is a standard JCT Homeowner Contract or Minor Works contract, it will include a dispute resolution mechanism — typically mediation, followed by adjudication if mediation fails.

For disputes without a formal contract:

Trading Standards can advise if you believe there has been a breach of consumer protection law
Membership bodies — if your contractor is a member of the Federation of Master Builders (FMB), the National Federation of Builders (NFB), or a similar body, those organisations have dispute resolution services
The courts — small claims (up to £10,000) via MCOL (Money Claim Online) is a realistic option for smaller disputes and doesn’t require a solicitor

What Not to Do

Don’t withhold payment beyond what is contractually justified — this can put you in breach and weaken your position
Don’t make threats you aren’t prepared to follow through with
Don’t conduct the dispute verbally — every meaningful exchange should be in writing

How to Enforce Remedial Work Without a Legal Battle

In the majority of cases, a well-documented snagging list sent professionally and promptly will result in remedial works being carried out. Most reputable contractors want to protect their reputation and would rather fix legitimate defects than face a formal dispute.

Practical steps that work:

Set a reasonable but firm deadline — give the contractor a specific date by which all snagging items must be addressed. Two to three weeks is typical for a standard list.
Confirm partial sign-offs — as items are completed to your satisfaction, confirm them in writing. This focuses the remaining dispute on a smaller number of items and demonstrates good faith.
Escalate methodically — if deadlines are missed, send a formal letter (not just an email) outlining the outstanding items, the breach of contract, and your intention to instruct a third party to complete the work at the original contractor’s cost if resolution isn’t reached within 14 days.
Get three quotes before instructing a third party — this demonstrates that you sought reasonable value and is important evidence if you end up in a cost-recovery dispute.
Document everything throughout — photographs with timestamps, a running log of all correspondence.

What to Expect from a Reputable Builder at Handover

A well-run project doesn’t just end — it’s handed over properly. Here’s what you should receive from any competent contractor at the point of practical completion:

Documentation pack:

Building Regulations Completion Certificate (or confirmation that it has been applied for)
Electrical Installation Completion Certificate (Part P compliance)
Gas Safe certificate for any gas works
Structural engineer’s sign-off notes (where applicable)
Flat roof or waterproofing warranties
Product manuals and warranties for installed appliances, boilers, windows, etc.
As-built drawings if the project involved structural changes

Practical handover:

A walkthrough of any systems installed (boiler controls, underfloor heating, MVHR units, etc.)
Keys, access codes and any new window or door keys
A clear process for reporting and resolving defects during the defects liability period

If a contractor cannot produce the above documentation, payment should be withheld until they can. These certificates are not optional — many of them are legal requirements and their absence will create serious problems if you ever come to sell or remortgage the property.

Don’t Sign Off Until You’re Genuinely Satisfied

Snagging is not pedantry. It is the final, legitimate opportunity to ensure that the money you have invested in your home has been spent on work that meets the standard you contracted and paid for.

The pressure to “just get it finished” is real — you want your life back, you may have been living in disruption for months, and there’s an awkward social dynamic when a builder is pushing for sign-off. But that pressure is precisely why having a clear, methodical process matters.

A thorough snagging inspection, a properly documented list, and a well-structured final payment arrangement are not signs of distrust — they are the hallmarks of a professional project. Any contractor worth working with will recognise that.

If you’re planning a renovation or extension in London and want to understand how we handle practical completion, documentation and defects liability from the outset, get in touch with the team at MB Build & Design. We’re happy to walk you through our handover process before you commit to anything.

Looking for more practical detail?

Concerned about recognising poor workmanship before handover? Read How to Spot Poor Workmanship Before Your Renovation Handover.
Need a clearer system for communicating with contractors and trades? Read How to Manage Your Contractor and Multiple Trades.
Need to understand planning permission for a London extension? Read London Planning Permission Checklist for Home Extensions.