New build and off-plan residential properties represent a significant portion of the buy-to-let acquisition market. Developer incentives, modern energy performance, lower maintenance costs in the early years and the ability to purchase ahead of completion at a fixed price are all commercially attractive features. But new build and off-plan acquisitions carry a different risk profile from second-hand property purchases, and a different set of due diligence priorities applies.

This guide covers the legal checks, documentation review and practical risk assessment that investors should complete before exchanging on a new build or off-plan property in the UK.

A new build purchase typically proceeds on a slightly different legal timetable from a resale purchase. The developer’s solicitors will issue a draft contract pack — often before the property is physically constructed — and exchange of contracts is followed by a period during which the developer completes the build, after which legal completion takes place. The gap between exchange and completion can range from a few months to several years for large-scale phased developments.

This deferred completion structure creates risk that does not exist in a standard resale purchase:

  • Developer insolvency — if the developer becomes insolvent between exchange and completion, the buyer’s deposit is at risk unless properly protected. Deposit protection mechanisms — including developer warranties, deposit protection insurance and escrow arrangements — should be confirmed before exchange.
  • Market value risk — property values may move significantly between exchange and completion. For investors exchanging off-plan at a price agreed twelve to twenty-four months before completion, the GDV at completion may be higher or lower than the exchange price.
  • Specification and quality risk — the finished property may differ from the specification agreed at exchange. The contract should clearly define the specification and the developer’s obligations where deviations occur.
  • Completion notice risk — most new build contracts include a developer’s right to issue a completion notice requiring the buyer to complete within a short period. Failure to complete on time can result in the buyer losing their deposit and being exposed to damages. Buyers who are relying on mortgage finance need to ensure their offer is in place and capable of being drawn down within the notice period.

Deposit Protection: Non-Negotiable

In any new build or off-plan purchase, deposit protection should be treated as non-negotiable. Investors should confirm before exchange that one of the following protections is in place:

  • Developer deposit protection insurance — a policy held by the developer that ensures the deposit is returned to the buyer if the developer becomes insolvent before completion.
  • Deposit held in escrow by a solicitor — the deposit is held by a neutral third party rather than released directly to the developer.
  • New Homes Quality Code protection — where the developer is registered with the New Homes Quality Board, certain consumer protections apply, though these vary in scope.

The form of deposit protection should be confirmed from the contract documentation. Where no adequate protection is in place, the investor should either negotiate its inclusion as a condition of exchange or reassess their willingness to commit.

Leasehold New Builds: An Area of Particular Caution

Many new build flats are sold on long leasehold terms — typically 125, 250 or 999-year leases — rather than as freehold. The leasehold structure itself is not inherently problematic, but a number of practices associated with new build leaseholds have attracted significant regulatory and media attention in recent years.

Investors should review new build leasehold documentation carefully for:

  • Ground rent provisions — the Leasehold Reform (Ground Rent) Act 2022 prohibits ground rent above a peppercorn on new leases granted from 30 June 2022. Leases granted before that date may still carry ground rent obligations. Any new build lease with a non-peppercorn ground rent warrants careful scrutiny.
  • Estate management charges — many new build developments include private estate management companies that charge annual fees for maintaining communal areas. These charges are not regulated in the same way as traditional service charges, and the amounts can increase significantly over time. Investors should confirm what estate management charges apply and what control leaseholders have over them.
  • Forfeiture provisions — lease forfeiture (where the landlord terminates the lease for breach of covenant) is a draconian remedy that should be available only in limited circumstances. The forfeiture provisions in the lease should be reviewed for reasonableness.
  • Restrictions on subletting and short-term letting — some new build development leases expressly prohibit buy-to-let letting or Airbnb-style short-term letting. These restrictions must be identified before exchange by any investor intending to let the property.

Build Warranties and Structural Guarantees

New build properties are typically accompanied by a structural warranty — the most common being the NHBC Buildmark warranty, the Premier Guarantee, or a similar product. These warranties provide protection to the buyer against major structural defects during the first ten years after completion.

The warranty certificate should be confirmed as in place before completion. Where a warranty is not available — which can occur for self-build properties, permitted development conversions or unlicensed developments — mortgage lenders may require a professional consultant’s certificate (PCC) instead. Investors should confirm their lender’s position on warranty requirements.

A structural warranty does not cover cosmetic defects, snagging items or specification variations — only major structural and water ingress defects. The first two years after completion are typically covered by a more comprehensive developer defects period, during which the developer is obligated to rectify reported defects. Investors who complete on a new build should ensure they report defects within the developer’s defects liability period.

Planning and Building Regulations on New Builds

New build properties should have the benefit of full planning permission and building regulations approval. The legal pack should include copies of the planning permission for the development (or the relevant reserved matters approval), the building regulations completion certificate, and the structural warranty certificate.

For permitted development conversions sold as new build units — a category that includes many Class MA commercial-to-residential conversions — the prior approval documentation should be included rather than a conventional planning permission. Investors should confirm that the prior approval conditions have been complied with and that the development has been completed in accordance with the approved drawings.

Realistic Yield Modelling for New Build Investment

New build properties frequently carry a premium over comparable second-hand stock, partly justified by lower maintenance costs, modern specification and energy performance, and partly a reflection of developer marketing. Investors should model rental yields against the actual purchase price — not against developer-projected rentals or overstated comparable values.

Common due diligence points for new build yield assessment include:

  • Service charge and estate management charge — these directly reduce net yield and should be confirmed from the lease, not estimated.
  • Void period assumptions — new build developments, particularly those completed in phases, can create localised supply concentrations that suppress initial rental demand.
  • Developer incentives — cashback, furniture packs or rental guarantees offered by developers can artificially inflate the apparent yield and are not sustainable beyond the incentive period. Lenders frequently reduce their valuation to strip out unsustainable incentives, which can affect the mortgage available.

Bidq reviews new build and off-plan legal packs — checking deposit protection, leasehold terms, planning compliance and subletting restrictions before you commit. See how Bidq’s solicitor-reviewed legal pack review works.