How to Spot Poor Workmanship Before Your Renovation Handover

You’ve spent months — sometimes years — planning your renovation or extension. The scaffolding has come down, the tradespeople have packed up, and your contractor is talking about handover. It feels like the finish line.

But handover is also the moment when poor workmanship hides in plain sight, and when homeowners most often accept things they shouldn’t. A crack is dismissed as “just settling.” A door that won’t close properly is called “something to sort later.” A damp patch behind a newly tiled wall stays invisible until six months after everyone’s gone.

This guide is about that gap — between a contractor saying the job is done and a job that actually is done. We’ll walk you through exactly what to look for, how to document it, and how to enforce remediation without the conversation turning hostile. We’ll also show you how MB Build & Design structures the build process so that most of these problems are caught long before handover day.

What Is a Snagging List — and Why It Matters More Than You Think

A snagging list is a formal record of defects, incomplete items, and work that doesn’t meet the agreed specification. It’s your legal and practical tool for holding a contractor to account before you release final payment.

Most homeowners treat it casually — a quick walk around with the builder, a few scribbled notes, a handshake. That’s a mistake.

Here’s why it matters:

Retention money depends on it. Most well-structured contracts include a retention clause — typically 2.5–5% of the total contract value — held back until defects are remedied. If you haven’t documented defects clearly, you have no basis to withhold that sum.
Defects liability periods are time-limited. Most contracts include a defects liability period of six to twelve months after practical completion. After that window closes, your leverage shrinks significantly.
Verbal agreements vanish. A builder saying “we’ll come back and sort that” is worth nothing if it isn’t in writing.

A proper snagging list, done methodically before you sign off on practical completion, is the difference between a renovation that’s truly finished and one that quietly costs you money for years.

The Red Flags Most Homeowners Miss (Room by Room)

Most people focus on the obvious — a missing light switch, a gap in the skirting, a chip in the paintwork. Those are worth noting, but they’re rarely the expensive problems. Here’s what to look for that typically gets missed.

Kitchen and Utility Areas

Grouting that isn’t flush or is already cracking. Hairline cracks in fresh grout suggest movement or poor prep. Full cracks suggest the substrate wasn’t properly fixed.
Cabinet doors that don’t align. This can mean units weren’t level when fitted — a problem that worsens over time and can affect integrated appliances.
Plumbing under the sink. Run every tap, fill the sink, then drain it fully. Watch underneath for drips at compression fittings. Check that waste pipes fall away from the unit — pooling water in a pipe creates smell and eventual blockage.
Extractor fans. Turn it on. Does air actually move? Is there a duct run to outside, or did someone vent it into the ceiling void? (This happens more than you’d expect.)
Worktop joints. Run your finger along any join. A step of more than a millimetre, or a visible gap, means the joint wasn’t cut properly or the carcasses weren’t level.

Bathrooms and Wet Rooms

Silicone at tray and bath edges. Silicone should be smooth, continuous, and applied after grouting — not as a fix for poor tile cutting. Any gap between the tray and wall, or between the bath and tiles, will let water in over time.
Shower trays and baths. Apply weight to each corner of a shower tray. It should be completely rigid. Any flex means it wasn’t properly bedded, and the silicone seal will fail within months.
Tile alignment across walls. Step back and look from an angle. Tiles that aren’t plumb, or grout lines that drift, suggest tiles were fixed directly to an uneven wall without proper prep — which also means adhesion may be compromised.
Underfloor heating response. If UFH was installed, switch it on and wait 20 minutes. The floor should warm evenly with no cold spots, which would indicate a failed zone or a connection that wasn’t pressure-tested.
Extractor run time and positioning. Building Regulations require bathroom extraction to run for a set overrun period after the light is switched off. Check this actually happens.

Extensions and New Build Spaces

Bi-fold and sliding door operation. These are precision items. Operate every panel through its full range. Any binding, jumping off the track, or draught when closed suggests the frame isn’t true or the door wasn’t adjusted properly after installation.
Windows and reveals. Check that every window opens, locks, and closes without force. Look at the reveals — are they square? Is there any visible gap between frame and masonry? That’s a thermal bridge and a future damp risk.
Floor level across the extension join. Where an extension meets the existing house, the floor level should be continuous. A lip or step suggests the extension floor build-up wasn’t calculated correctly against the existing DPC level.
External pointing and render. Look for cracks, voids, or areas where render is hollow (tap it lightly — a dull thud rather than a solid knock). External defects let water in and degrade fast through a London winter.

Loft Conversions

Roof light operation and seals. Open every Velux or roof light. Check the flashings are tight with no visible daylight gap. Condensation on the inside of a new roof light within days of fitting means the seal is compromised.
Staircase geometry. Building Regulations specify minimum headroom and maximum riser height. Measure both. A staircase that was squeezed in to save space may not comply — which is a problem when you come to sell.
Fire doors. Any loft conversion in England requires fire doors at certain points. Check they are correctly rated (look for the certification mark on the top edge), that they self-close fully, and that intumescent strips are fitted.
Structural steels. Loft conversions involve significant structural work. You won’t be able to see the steels once finished, which is exactly why you should have asked for — and received — photographic evidence of installation before boarding over.

Structural and Hidden Work: What You Can’t See Can Hurt You

This is the category that causes the most serious long-term problems and the hardest disputes, because by handover the evidence is behind walls and under floors.

The only reliable protection is to establish a paper and photographic trail during the build. Specifically:

Before any wall or floor is closed up, you should have:

Photographs of all structural steel positions, connections, and bearing points
Photographs of all insulation (type, depth, continuity — gaps in insulation are invisible but costly)
Photographs of all electrical first fix (cable runs, back-box positions, any earthing arrangements)
Photographs of all plumbing first fix (pipe routes, isolation valves, any joints concealed within walls)
Photographs of any damp proof membrane or DPC detailing
A copy of any structural engineer’s inspection sign-off at intermediate stages

If your contractor can’t or won’t provide these, that itself is a red flag. Reputable builders have no reason to avoid photographing their own work — they know it protects them too.

For structural work specifically, your Building Control inspector will have made interim visits and should have signed off on the structure before it was concealed. Ask for the inspection record. If Building Control visits weren’t arranged, the work has not been inspected — and that is a serious compliance issue regardless of how it looks on the surface.

How a Professional Builder Stages Quality Checks Throughout the Build

The single most important thing to understand about snagging is this: a competent contractor doesn’t wait until handover to find problems. Quality is checked at every stage, so that defects are addressed when they’re still accessible and inexpensive to fix.

At MB Build & Design, we structure quality control around defined build stages — not because it’s industry best practice (though it is), but because it protects everyone. A problem caught behind plasterboard costs an hour to fix. The same problem caught after tiling and decorating costs days and thousands.

Here’s how that looks in practice:

Foundation and Structure Stage

Before any above-ground work proceeds, we check that foundations are poured to the correct depth and specification, structural steels are correctly positioned and bedded, and Building Control have made their interim inspection. This isn’t optional — it’s the point at which structural errors become catastrophic to unpick later.

First Fix Stage (Before Boarding)

All electrical, plumbing, and HVAC first fix is inspected and photographed before walls are boarded. This is also when we confirm insulation continuity — particularly around structural elements like steels, where thermal bridging is easy to miss and expensive in heat loss.

Plastering and Drying Stage

We check that plaster is applied to the correct thickness, that surfaces are plumb and flat within tolerance (3mm deviation over a 2-metre straight edge is the standard), and that adequate drying time is allowed before second-fix or decoration begins. Decorating over wet plaster causes failures that look like poor painting but are actually a substrate problem.

Second Fix and Finishing Stage

This is when kitchens, bathrooms, and joinery go in, and it’s where most visible snagging originates. We walk every room against the specification before our finishing team leaves site.

Pre-Handover Walk

Before we invite a client to a handover inspection, we conduct our own internal walk with the site manager. Any items identified are resolved — or if they require a specialist return visit, they’re documented and scheduled with a committed date before handover paperwork is signed.

This approach doesn’t eliminate snagging lists — no build does. But it means the list at handover is genuinely minor rather than a catalogue of failures.

How to Document Defects Properly So They Actually Get Fixed

Documentation is the difference between a snagging list that gets acted on and one that gets ignored. Vague descriptions give contractors room to manoeuvre. Specific, evidenced records don’t.

The Format That Works

Create a numbered list (not bullet points — numbered items are easier to track and reference in correspondence). For each item:

Location — Room, wall, specific position. “Bathroom” is not sufficient. “Bathroom, south-facing wall, third tile from left on the second row from floor” is.
Description of defect — What is wrong, not what you want done about it. “Grout line cracked” not “regrout bathroom.”
Date photographed — Every item should have at least one photograph, timestamped.
Reference to specification — Where possible, note what the agreed specification or Building Regulations require. “Installation should comply with BS 8000-11” is harder to argue with than “this looks wrong.”

Tools

You don’t need specialist software. A shared Google Doc or a simple spreadsheet with an accompanying photo folder works well. What matters is that it’s timestamped, shareable, and kept somewhere you control — not in a WhatsApp thread that can be deleted.

Timing

Conduct your snagging inspection before you sign practical completion. Practical completion is the formal moment at which the contract shifts — defects liability starts, your retention may be partially released, and your ability to refuse final payment becomes more complex. Many homeowners sign off because they feel social pressure to be agreeable. Don’t. A reasonable contractor will understand and accommodate a thorough inspection.

Also conduct a second inspection at the end of the defects liability period. Some defects — particularly those related to movement, moisture, or seasonal change — won’t be visible on the day.

How to Enforce Completion Without Contractor Pushback

Most disputes don’t start with bad faith — they start with ambiguity. A contractor who genuinely believes the job is done to standard will feel aggrieved by a snagging list. A contractor who knows there are problems may play for time, hoping you’ll give up. The approach that works in both cases is the same: professional, specific, and in writing.

Step One: Issue the Snagging List Formally

Send it by email (so it’s dated and logged), addressed to the contractor’s business contact. Reference your contract and the date of your inspection. Keep the tone factual — no accusations, no frustration. Attach your photographs. Request written acknowledgement of receipt and a proposed remediation schedule within a specific number of days (five to seven working days is reasonable).

Step Two: Agree a Remediation Schedule in Writing

Don’t accept “we’ll be back next week.” Get a written schedule: which items will be addressed, by whom, and on which dates. This schedule becomes your basis for any future escalation.

Step Three: Inspect Remediated Work Before Releasing Retention

When the contractor says remediation is complete, go back to your list item by item. Re-photograph anything that was repaired. Only release retention — or sign any completion documentation — once you are satisfied, not once you’re told to be.

Step Four: Escalation if Needed

If a contractor refuses to return, disputes your list without engaging with the specifics, or goes silent:

Check your contract for a disputes procedure — many JCT-based contracts include adjudication as a first step.
Contact your trade association — if your contractor is a member of the Federation of Master Builders, TrustMark, or a similar body, those organisations have complaints processes that matter to members.
Seek independent assessment — a chartered building surveyor can inspect and report on defects independently, providing evidence that carries weight in any dispute or legal action.
Withhold the retention — this is exactly what it exists for. If you have documented defects and a contractor is not remedying them, you are entitled to withhold the sum contractually set aside for this purpose.

What to Do If Your Contractor Disappears or Refuses to Return

This is, unfortunately, not a rare scenario in London’s renovation market. Contractors who take final payment early (another red flag — never pay ahead of stage), or who fold under pressure, sometimes simply stop responding.

If this happens:

Document everything immediately. Screenshot conversations. Save all emails. Note every date and time you attempted contact. This creates the record you’ll need.

Check whether you have any payment protection. If you paid by credit card (even partially), Section 75 of the Consumer Credit Act gives you a claim against the card provider for misrepresentation or breach of contract. If you paid a deposit and the contractor is a sole trader who has become insolvent, you may be able to claim through the insolvency process.

Get an independent assessment before starting remedial work yourself. If you appoint a new contractor to fix the first contractor’s defects, get a surveyor’s report first — both to establish what went wrong and to provide evidence for any claim.

Consider the small claims track. For claims up to £10,000, the small claims court process is designed to be accessible without legal representation. For larger claims, a solicitor’s letter before action often prompts resolution before proceedings begin.

The best protection against this outcome is choosing the right contractor in the first place — which brings us to how we approach this.

How MB Build & Design Handles Snagging and Handover

We’re a London-based construction and renovation company, and we’re going to be straightforward about this: we’re not writing this guide to be altruistic. We’re writing it because the clients who arrive at a project knowing what good looks like are the clients we work best with.

Here’s how we structure the handover process on every project we manage:

Stage photography throughout. We photograph first fix across all trades before boarding, and we share this with clients as a matter of course. You shouldn’t have to ask.

Internal snagging walk before client handover. Our site manager walks every project against the specification before we invite clients to their handover inspection. Items identified internally are resolved or scheduled before that meeting.

Written handover pack. This includes your O&M manuals for installed systems and appliances, building regulation completion certificates, warranties for structural elements and specialist installations (waterproofing, for example), and any planning conditions that required sign-off.

Defects liability period. We operate a formal defects liability period on all projects, during which we return to address any defects at no additional cost to you. We’d rather know about a problem and fix it than have a client living with it.

Clear retention terms in contract. Our contracts set out retention clearly — the percentage held, the trigger for release, and the process for remediation. We hold ourselves to the same standard we’d expect you to hold us to.

We’re not going to tell you we never have snagging items. Every construction project does. What we can tell you is that the way a contractor handles them tells you everything about how they operate.

Final Checklist: Your Pre-Handover Inspection in Plain English

Use this as your starting point before any handover walk. Add items specific to your project and specification.

Documentation

Building Regulations completion certificate received or applied for
Stage photographs of all first-fix work received
Structural engineer’s inspection sign-offs received
Warranties for specialist works (waterproofing, structural, specialist windows) received
O&M manuals and appliance documentation received
Planning conditions — any post-construction sign-offs required?

Structure and Envelope

No visible cracks in masonry, render, or internal plaster beyond hairline settlement cracking
All windows open, close, lock, and seal without force
All external doors operate correctly; draught seals intact
Extension floor level continuous with existing house floor
External pointing and render solid — no hollow areas

Wet Areas

All taps, showers, and baths run and drain; no drips at fittings
Silicone continuous and intact at all wet area junctions
Shower tray rigid with no flex
Underfloor heating warms evenly (if applicable)
Extractor fan operates and runs on overrun after light off

Electrics

Every socket and switch operates
All lighting circuits tested
Consumer unit labelled correctly and Part P certificate received
Any smart systems or heating controls commissioned and demonstrated

Joinery and Finishes

All doors open, close, and latch without binding
Skirting and architrave fully fixed; no gaps at corners
Decoration complete — no missed patches, runs, or unfinished edges
Kitchen units level and aligned; all hinges adjusted

Mechanical

Boiler commissioned; gas safe certificate received
All radiators heat up and can be balanced
Any MVHR or ventilation system set to correct flow rates
Underfloor heating manifolds accessible and labelled

Snagging isn’t an adversarial process — or it shouldn’t be. It’s the final quality check on a significant investment, and a contractor who takes it seriously is one you can trust with your property. If yours pushes back on a reasonable, documented inspection, that tells you something important.

If you’re planning a renovation, extension, or loft conversion in London and want to understand how we’d approach your project — from first consultation through to a handover you’re genuinely satisfied with — get in touch with the MB Build & Design team for a no-obligation conversation.

Looking for more practical detail?

Preparing for practical completion and the final invoice? Read Snagging & Handover: Your Final Check Before Payment.
Need a clearer system for communicating with contractors and trades? Read How to Manage Your Contractor and Multiple Trades.
Planning a renovation and unsure where to begin? Read How to Plan a Home Renovation Without the Usual Surprises.