Practical Completion in London Construction: What It Means, When It's Achieved, and What Happens After

**The legal meaning of practical completion**:

Practical completion (PC) is a concept rooted in construction contract law. The standard JCT (Joint Contracts Tribunal) building contracts — the most commonly used contract forms in UK residential construction — use the term 'Practical Completion' to describe the stage at which the works are complete for all practical purposes: fit for occupation and use, with only minor defects remaining that do not prevent use.

The precise legal threshold for practical completion has been the subject of considerable case law in the English courts. The leading position (from Emson Eastern Ltd v EME Developments Ltd [1991] and Mears Construction Ltd v Samuel Williams & Sons Ltd [1977], and confirmed more recently) is that:

• •Works can be practically complete even if there are minor defects that do not prevent the practical use of the building
• •A 'snag list' of minor defects does not prevent practical completion from being certified
• •Works cannot be practically complete if there are significant outstanding structural or performance issues — large areas of unfinished work, major defects in weatherproofing, or systems that are not operational

• For a typical London residential extension or loft conversion, practical completion is the point at which:
• •The structural works, roof, windows, and doors are complete and the extension is weathertight
• •All first-fix and second-fix services (electrical, plumbing, heating) are operational
• •Plastering, tiling, joinery, and decorating are substantially complete
• •The client can occupy and use the extension (live in the loft bedroom; use the kitchen in the extension)
• •Minor remaining items (a paint touch-up; a tile to be replaced; a door handle to be adjusted) are listed on a snagging list for completion during the defects liability period

**What practical completion triggers in the contract**:

Practical completion is a contractual milestone that has significant legal and financial consequences. In a JCT Minor Works or JCT Homeowner/Occupier contract (the contract forms typically used for London residential extensions), practical completion triggers:

*1. Transfer of risk from contractor to client*: Once practical completion is certified, the risk of loss or damage to the works (from fire, flood, accident, etc.) passes from the contractor to the client. The contractor remains liable for defects caused by defective workmanship or materials, but not for accidental damage after practical completion.

*2. Release of retention*: Under contracts that include a retention mechanism (typically 5% of the contract sum retained during the works), practical completion triggers the release of half the retention (2.5%). The remaining half (2.5%) is released at the end of the defects liability period.

*3. Start of the defects liability period*: The defects liability period (typically 12 months for a standard London residential extension under JCT terms) begins at the date of practical completion. During this period, the contractor has the right and obligation to return to make good any defects that emerge and are attributable to defective workmanship or materials.

*4. Relief from liquidated damages*: Where the contract includes a liquidated and ascertained damages (LAD) clause (a pre-agreed daily or weekly rate the contractor pays if they fail to complete on time), practical completion ends the contractor's liability for LADs.

*5. Commencement of the limitation period*: Practical completion starts the clock running on the limitation period — the time within which the client can bring a contractual claim against the contractor. Under a simple contract (contract not under deed), the limitation period is 6 years from practical completion. Under a contract executed as a deed, the limitation period is 12 years.

**How practical completion is certified in a London residential project**:

In a formal JCT contract for a London residential extension, practical completion is certified in writing by the contract administrator (typically the architect or project manager, where one is appointed). The certificate of practical completion records the date of practical completion and formally triggers the contractual consequences above.

• For residential projects where no architect or contract administrator is appointed (the majority of London domestic extensions where the client contracts directly with the principal contractor), practical completion is agreed between the client and the contractor — typically by agreement that the works are complete to a mutually acceptable standard, evidenced by:
• •A written handover letter from the contractor listing any remaining snag items and confirming practical completion
• •A snagging inspection by the client (and optionally by an independent building surveyor)
• •The client taking possession of the keys and first occupation of the completed space

**What the defects liability period covers**:

The defects liability period (DLP) is a defined period after practical completion during which the contractor has the right and obligation to return to make good any defects that emerge. The standard DLP under JCT Minor Works is 12 months (though this can be varied by agreement — some contracts use 6 months, some use 24 months).

• During the DLP, the contractor is obliged to make good at their own cost any defect that:
• •Is attributable to a failure to comply with the contract specification or drawings
• •Is attributable to defective workmanship (poor installation, incorrect construction technique)
• •Is attributable to materials that were defective or did not comply with the specification

• The contractor is NOT obliged under the DLP to make good:
• •Fair wear and tear (normal deterioration from use)
• •Damage caused by the client or a third party
• •Items that were specifically excluded from the works in the contract
• •Client-supplied materials that have failed (the client supplied the tiles; the tiles have cracked — the contractor installed them to specification; the failure is in the tiles, not the installation)

*Practical application in London residential projects*:

• The DLP is particularly valuable for:
• •Plaster and paint movement and cracking (particularly in a new extension on London clay, where the structure settles slightly in the first year; hairline cracking in plaster during the first winter after completion is very common and should be made good by the contractor as part of the DLP)
• •Flat roof membrane performance (if the membrane leaks in the first wet season after completion)
• •Window and door adjustment (bi-fold door alignment may need adjustment after the first full thermal cycle)
• •Grouting or sealant defects in tiling
• •Joinery shrinkage (timber architraves and skirtings can open at joints in the first year as the building dries out)

**How to manage the defects liability period effectively**:

*1. Keep a running snagging list during the DLP*: As defects emerge during the first year, the client should keep a written list — photograph each defect with a date; describe the location and nature of the defect. This list is the evidence base for the DLP claim at the end of the period.

*2. Report significant defects promptly*: For significant defects (particularly waterproofing failures, structural issues, or anything affecting the safety or usability of the building), report to the contractor immediately and in writing. Delayed reporting of a defect that is getting worse (a slow flat roof leak that is saturating the insulation) reduces the chance of a straightforward repair and may give the contractor a basis to argue that the damage was made worse by the client's failure to report promptly.

*3. End-of-DLP inspection*: At the end of the DLP (12 months after practical completion), an inspection should be arranged with the contractor to walk through all outstanding snagging items and agree how and when they will be made good. The contractor is then obligated to carry out this work before issuing the final account.

*4. Final retention release*: Where the contract includes a retention, the remaining half of the retention (typically 2.5% of the contract sum) is released once all DLP defects have been made good to the client's reasonable satisfaction — not simply at the end of the 12-month period if significant defects remain unresolved.

**What the Building Control Completion Certificate signifies**:

• The Building Control Completion Certificate is separate from practical completion as a contractual concept. It is issued by Building Control (the Local Authority Building Control or an Approved Inspector) once they are satisfied that the works comply with Building Regulations. The Building Control Completion Certificate:
• •Confirms Building Regulations compliance
• •Is required for conveyancing (buyer's solicitors will require the CC before exchange)
• •Does NOT certify that the works meet the contract specification or that there are no defects
• •Can be issued at a different time from practical completion (sometimes before; sometimes several months after, depending on when the final BC inspection takes place)

For London residential extensions and loft conversions, the Building Regulations Completion Certificate is typically sought during the final stages of the project — RCB requests the final Building Control inspection once the second-fix is substantially complete and the building is ready for occupation.

**What is snagging?**

Snagging is the process of identifying minor defects, incomplete items, and finishing issues in a newly completed construction project — and recording them on a 'snag list' so that they can be made good before or shortly after practical completion.

• In London residential construction, snagging typically covers:
• •Paint issues: runs, drips, missed areas, uneven coverage, marks on walls or ceilings
• •Plaster defects: small cracks, scratches, or areas of uneven plaster that require touching up
• •Joinery issues: doors that bind or do not close properly; gaps in architrave or skirting joints; window boards not fully seated; balustrade loose or not vertical
• •Tiling defects: cracked tiles; uneven grout joints; sealant not applied or incomplete
• •Electrical issues: sockets or switches not flush; light fittings not fully secured; extractor fans not tested
• •Plumbing issues: taps not fully secure; shower head loose; bath sealant not applied; basin waste not draining freely
• •External issues: mortar spots on brickwork; render patches; external sealant gaps; drainage gulley not set flush

Snagging is normal — virtually every new build and extension has a snag list at practical completion. The question is not whether there are snags (there almost always are), but whether they are minor items that do not prevent practical use of the space, or significant defects that prevent practical completion from being achieved.

**How to carry out a snagging inspection at practical completion**:

• *Before the inspection*:
• •Visit the site during daylight hours (natural light is best for identifying paint and plaster issues)
• •Bring a torch for checking inside wardrobes, under staircases, and in loft voids
• •Test every electrical socket and switch, light fitting, and extractor fan
• •Test all taps, showers, and toilets for operation and leaks
• •Open and close every door, window, and bi-fold panel
• •Check all sealant joints (bath, shower, basin, worktop, external window reveals)
• •Walk through every room systematically — don't rush

• *Recording the snag list*:
• •Photograph every defect clearly — get close enough that the nature of the defect is obvious in the photo
• •Number each defect sequentially on the snag list
• •Note the room/location and a brief description ('Living room north wall, 1.5m above floor — paint drip, approximately 100mm long')
• •Do not over-snag (listing everything as a snag regardless of significance) — this creates arguments and bad feeling. Focus on genuine defects, not subjective aesthetic preferences about colour matching or texture

• *Delivering the snag list to the contractor*:
• •Provide the snag list in writing (email with the photographs attached) within a few days of the inspection
• •Agree a timescale for the snag items to be made good — typically 2–4 weeks for a standard residential snag list

**RCB's approach to practical completion and handover**:

• For RCB-managed London extension and loft conversion projects, practical completion is managed as follows:
• •The site manager conducts an internal pre-completion snagging walk-through in the week before the planned handover date, and addresses items before the client's inspection
• •A handover meeting is arranged with the client — the client is walked through the completed works; all systems (heating, electrical, plumbing) are demonstrated
• •A handover pack is provided: Building Control documentation; any warranties from specialist subcontractors (flat roofer's guarantee; window manufacturer's warranty); the electrical installation certificate (EIC); the Gas Safe certificate where relevant; instructions for any systems installed
• •Any items on the client's snag list that were not resolved before handover are recorded and agreed to be made good within 14 days
• •A 12-month defects liability period runs from the date of practical completion