How to Get a Mortgage on a New Build Home: The Step-by-Step Process from DIP to Completion

The New Build Mortgage Timeline at a Glance

Total typical timeline: 10-26 weeks from reservation to completion. Off-plan purchases can extend this to 6-18 months, which creates significant mortgage management challenges.

Stage 1: Decision in Principle (DIP)

A Decision in Principle (also called an Agreement in Principle or Mortgage in Principle) is a statement from a lender confirming how much they'd be willing to lend you, based on a preliminary assessment of your income, outgoings, and credit history.

What You Need

• Your income details (salary, bonuses, overtime, any additional income)
• Your monthly outgoings (existing debts, credit cards, loans, childcare)
• Your deposit amount
• Basic personal details (address history, employment history)

How It Works

Most DIPs can be obtained online or over the phone within minutes. The lender runs a soft credit check (which doesn't affect your credit score with most lenders) and provides a certificate stating the amount they'd lend. A DIP is typically valid for 60-90 days.

Why You Need It Before Reserving

Developers require a DIP before they'll accept a reservation. It proves you're a serious buyer who can realistically afford the property. Without one, the developer won't take your reservation fee.

New Build-Specific Tip

Get your DIP from a lender or broker who handles new build mortgages. Not all lenders lend on new builds, and some have restrictions on specific developers, construction types, or LTV ratios. There's no point getting a DIP from a lender who'll later decline your full application because they don't lend on new builds.

A whole-of-market mortgage broker can check new build eligibility as part of the DIP process. See our guide to getting the best deal for more on choosing between brokers and going direct.

Stage 2: Reserve the Property

Once you have your DIP, you visit the developer's sales office and pay a reservation fee (typically £500-£1,000, though some developers charge up to £2,000). This takes the property off the market for a set period — usually 28 days — while you progress your mortgage and instruct solicitors.

What You Provide to the Developer

• Your DIP certificate
• Proof of identity (passport, driving licence)
• Proof of address
• Proof of deposit funds (bank statements showing savings, LISA statements, gifted deposit letter if applicable)
• Your solicitor's details

Key Things to Understand

• The reservation fee is usually non-refundable if you pull out for reasons unrelated to the mortgage or survey
• It's typically deducted from your purchase price at completion
• The reservation agreement will specify a deadline for exchanging contracts — ask what happens if the build is delayed
• Negotiate now — once reserved, your bargaining power decreases. Discuss incentive packages, upgrades, and any price adjustments before signing the reservation form

Stage 3: Full Mortgage Application

The full application is the detailed submission to your chosen lender. This is where the serious documentation comes in.

Documents You'll Need

What the Lender Assesses

• Affordability — can you comfortably afford the monthly payments, including a stress test at a higher interest rate (typically the rate + 3%, or a minimum of around 7-8%)?
• Credit history — full credit check including CCJs, defaults, late payments, and existing borrowing
• Deposit source — anti-money-laundering requirements mean the lender must verify where the deposit came from
• Property suitability — the lender will check whether they lend on the specific developer, construction type, and property type

New Build-Specific Issues at Application

• Developer incentives must be declared. Any incentives offered by the developer — cashback, stamp duty paid, flooring/kitchen upgrades, white goods packages — must be disclosed on the application. Incentives above a certain threshold (typically 5% of the purchase price) can reduce the amount the lender will advance.
• Off-plan timing. If the property won't be ready for several months, you need a lender who offers extended mortgage offer validity. Standard offers expire after 6 months. Some new build specialists offer 9 or 12 months.
• Construction type. The application should confirm the construction method (brick and block, timber frame, steel frame, etc.). Some lenders restrict lending on certain construction types.

Stage 4: Valuation

The lender instructs a surveyor to value the property. This is not a survey for your benefit — it's for the lender to confirm the property is worth enough to secure the loan.

How New Build Valuations Work

New build valuations are different from standard property valuations because the surveyor often has limited comparable evidence. They assess value based on:

• Recent sales on the same development (if any)
• Sales of similar new builds in the area
• Resale values of equivalent properties nearby
• The specification and size of the property
• The developer's pricing relative to the local market

For Off-Plan Properties

If the property isn't built yet, the surveyor may conduct a "desktop valuation" based on plans, specification, and comparable evidence — or delay the valuation until the property is at a sufficient stage of construction. Some lenders won't instruct the valuation until the property has reached roof level or is near completion.

The Down-Valuation Risk

This is one of the biggest risks in new build purchases. A down-valuation occurs when the surveyor values the property below the purchase price. For example, you're buying at £350,000 but the surveyor values it at £330,000.

Consequences of a down-valuation:

• The lender will only lend based on the lower valuation, not the purchase price
• You need to find the shortfall yourself — in this example, an extra £20,000
• Your effective LTV changes, potentially pushing you into a worse rate band

Options if you're down-valued:

1. Challenge the valuation — provide comparable evidence (other sales on the development, Land Registry data) that supports the purchase price. Your broker or solicitor can submit this to the lender.
2. Negotiate with the developer — ask the developer to reduce the price to match the valuation. Some will; some won't.
3. Try a different lender — valuations are opinions, and different surveyors may reach different conclusions. Your broker can submit to another lender whose panel surveyor may value more favourably.
4. Find additional funds — if you can cover the shortfall from savings or family support, the purchase can proceed at the original price.
5. Walk away — if the numbers don't work, you can withdraw. You'll lose your reservation fee but avoid buying an overpriced property.

Stage 5: Mortgage Offer

If the application passes all checks and the valuation is satisfactory, the lender issues a formal mortgage offer. This is the document confirming they will lend you the specified amount, on the specified terms.

What the Offer Contains

• The loan amount
• The interest rate and mortgage type (fixed, tracker, etc.)
• The monthly payment amount
• The mortgage term
• Any conditions that must be met before funds are released
• The offer expiry date

Offer Validity — The Critical New Build Issue

Standard mortgage offers are valid for 6 months from the date of issue. For new builds — especially off-plan purchases — this is a major issue. If your property isn't ready to complete within 6 months, the offer expires and you need to reapply.

What happens when an offer expires:

• The lender reassesses your application with current criteria and rates
• Rates may have changed — your new offer could be at a higher (or lower) rate
• Your circumstances may have changed (new debts, changed employment) — you might not get the same offer
• Another credit check is run, adding a footprint to your credit file

Solutions:

• Ask the lender for an extension — some will extend by 3 months without a full reassessment
• Choose a lender that offers 9 or 12-month offer validity for new builds
• Time your application carefully — don't apply too early if the build has months to go
• Your broker can advise on optimal application timing based on the build schedule

Conditions on the Offer

Mortgage offers often come with conditions that must be satisfied before funds are released:

• Satisfactory searches — your solicitor must complete local authority searches, environmental searches, and other legal checks
• Building warranty confirmation — the lender needs proof that an NHBC (or equivalent) warranty is in place. This is standard for new builds.
• Roads and sewers agreement — confirmation that the roads and sewers serving the development will be adopted by the local authority (or satisfactory arrangements are in place)
• Final inspection report — for off-plan properties, the lender may require a satisfactory NHBC final inspection before releasing funds

Stage 6: Conveyancing (Legal Work)

Conveyancing runs in parallel with the mortgage application. Your solicitor handles the legal transfer of property ownership. New build conveyancing is more complex than standard conveyancing and takes longer.

Why New Build Conveyancing Takes Longer

• The developer's solicitor provides a large pack of legal documents specific to the development — transfer deed, management company details, restrictive covenants, estate charge schedules, planning permissions, building control approvals
• Your solicitor must review all of these, raise enquiries, and ensure everything is satisfactory
• If the development is leasehold, the lease needs thorough review
• Roads and sewers adoption status needs verification
• Management company arrangements and estate charges need scrutiny
• Some developers use their own standard contract terms that your solicitor may need to negotiate

Choosing a Solicitor

• Use a solicitor experienced in new build conveyancing — the documentation is specialised
• Avoid the developer's recommended solicitor if possible — they may prioritise the developer's timeline over your interests
• Check the solicitor is on your mortgage lender's approved panel — if they're not, you'll need a separate solicitor to handle the lender's requirements, adding cost and complexity
• Expect to pay £1,200-£2,500 for new build conveyancing including disbursements (searches, Land Registry fees, etc.)

Key Legal Checks for New Builds

Your solicitor should verify:

• The developer owns the land and has planning permission for the development
• Building regulations approval and completion certificates are in order
• The structural warranty (NHBC or equivalent) is confirmed
• Any restrictive covenants on the property (and whether they're reasonable)
• Estate charge arrangements — what you'll pay annually, what it covers, and how it can increase
• Whether roads, footpaths, and sewers are adopted or will be adopted under Section 38/Section 104 agreements
• Freehold vs leasehold status — and if leasehold, the full terms of the lease
• Any overage clauses or developer rights over the land

Stage 7: Exchange of Contracts

Exchange is the point of no return. Once contracts are exchanged, both you and the developer are legally bound to complete the purchase. Pulling out after exchange incurs severe financial penalties.

What Happens at Exchange

• Your solicitor and the developer's solicitor exchange signed contracts
• You pay the exchange deposit — typically 10% of the purchase price (your mortgage deposit goes towards this, plus any additional funds required)
• A completion date is agreed — usually 1-4 weeks after exchange for new builds, sometimes same day
• You're now legally committed — buildings insurance should start from exchange

New Build Exchange Considerations

• Notice period: Developers often give you a short notice period (sometimes just 10 working days) to exchange once they confirm the property is ready. Be prepared — have your mortgage offer and legal work as advanced as possible.
• Long-stop date: For off-plan purchases, there should be a "long-stop date" in the contract — the latest date by which the developer must complete the build. If they miss it, you can withdraw and recover your reservation fee and deposit.
• Snagging before exchange: Ideally, request a pre-completion inspection before exchange. This gives you maximum leverage. See our snagging guide for how to arrange this.

Stage 8: Completion

Completion is the day the property becomes legally yours.

What Happens

1. Your mortgage lender transfers the loan funds to your solicitor
2. Your solicitor adds your deposit and any other funds, then transfers the full purchase price to the developer's solicitor
3. Once the developer's solicitor confirms receipt, the keys are released — usually from the site sales office
4. Your solicitor registers the property in your name at the Land Registry
5. Your solicitor pays any stamp duty due on your behalf (using funds you've provided)

Completion Day Practicalities

• Funds transfer typically happens between 10am and 2pm — don't expect to collect keys first thing in the morning
• The developer will usually arrange a handover appointment where the site manager walks you through the property, shows you how systems work (boiler, heating, alarms), and hands over manuals and certificates
• Take meter readings (gas, electric, water) and photograph them
• Check that everything included in the specification is present and in the condition expected
• Note any obvious defects for your snagging report

After Completion

• Your first mortgage payment is usually due one month after completion
• Set up a direct debit with your lender immediately
• Register for council tax
• Transfer utilities into your name (or set up new accounts)
• Register your NHBC warranty (or ensure the developer has done so)
• Begin your snagging inspection within the first 2-4 weeks

Common New Build Mortgage Problems (and How to Handle Them)

Build Delays and Mortgage Offer Expiry

The most common new build mortgage problem. Your offer was issued 5 months ago, the developer has delayed completion by 3 months, and the offer expires next month.

Action plan:

1. Contact your lender (or broker) immediately when you learn of the delay
2. Request an offer extension — many lenders will extend by 3-6 months without a full reassessment
3. If the lender won't extend, you'll need to reapply — your broker can manage this, potentially with a different lender if rates have improved
4. Keep the developer informed — if the delay is their fault and it causes you to lose a favourable rate, this strengthens any claim for compensation

Down-Valuation

The surveyor values the property below the purchase price. Covered in detail in Stage 4 above.

Incentive Declaration Issues

Developer incentives above 5% of the purchase price trigger specific lender rules. The lender may reduce the property value for lending purposes by the amount of the incentive, effectively requiring a larger deposit from you.

Example: You're buying at £300,000 with a £15,000 incentive package (5% — at the threshold). The lender may treat the property value as £285,000 for LTV purposes, meaning your deposit needs to cover the gap.

Prevention: Discuss any incentive packages with your broker before agreeing them with the developer, so you understand the impact on your mortgage.

Changed Circumstances During the Process

If your circumstances change between application and completion — new job, salary reduction, additional debt, pregnancy — you may need to inform the lender. In some cases, the lender will reassess your application. Your broker can advise on what needs to be disclosed and the potential impact.

Leasehold Ground Rent Issues

Some lenders will not lend on leasehold properties where the ground rent exceeds a certain level or includes doubling clauses. If your new build is leasehold, your solicitor and broker should check the ground rent terms against lender requirements early in the process.

How Long Does the Whole Process Take?

The key for off-plan buyers is timing the mortgage application so the offer doesn't expire before completion. Your broker should advise on optimal timing based on the developer's build schedule and the lender's offer validity period.

Checklist: What You Need at Each Stage

Key Takeaways

• Get a DIP from a lender or broker who handles new build mortgages before you start viewing properties
• The full application requires extensive documentation — start gathering it early
• Down-valuations are more common on new builds — have a plan if it happens
• Mortgage offers typically last 6 months — for off-plan purchases, choose a lender with extended validity or time your application carefully
• Declare all developer incentives to the lender — undisclosed incentives can void your mortgage offer
• New build conveyancing takes longer than standard — allow 8-16 weeks for the legal work
• Use a mortgage broker with new build experience — they understand the complications and know which lenders work best for new builds
• For help choosing the right mortgage type, see our mortgage types guide
• For affordability guidance, see our mortgage affordability guide