Buying off plan: what to know about a new build

What buying off-plan means

Buying off-plan means agreeing to buy a home before it is built, or while it is still being built. You choose from plans, a site layout, a show home and a specification, rather than walking round the home itself.

The legal steps are the same as for any new build: you reserve, your solicitor does the legal work, you exchange contracts, and later you complete. The difference is the gap between exchange and completion. With a finished home, completion can follow within days or weeks. With an off-plan home, it can be many months.

The New Homes Quality Board's buyer guide says that early in the build, a builder will usually give you a season as an estimate of when the home will be ready, then a more specific timescale as the build goes on. The precise completion date is not usually confirmed until about two weeks beforehand.

Why buyers choose off-plan

• The pick of the plots. Early buyers can choose the plot with the best garden, aspect or position on the development.
• A say in the finish. The NHQB guide notes that buying off-plan lets you choose things like kitchen fittings, paint colours, tiles and floor coverings, depending on the build stage.
• Time to save. With completion months away, you have longer to build up your savings for moving costs and furnishing, though your deposit is due at exchange.
• Incentives. Builders may offer builder-stated incentives to early buyers. Get any offer in writing, and compare the price with similar homes nearby before you value an incentive. The new-build premium tool helps, and new-build incentives shows where builders are offering them.

You can find developments that are not yet selling on coming soon, and every new home on sale by place in new homes.

The risks to plan for

Buying off-plan is a commitment to something that does not exist yet. The main risks are:

• Delays. Weather, materials and labour can all push completion back. That matters if you are renting, selling, or relying on a mortgage offer that expires.
• Changes to the home. The builder may change materials or details as it builds.
• The price against the market. You agree the price at exchange. By completion, the local market may have moved up or down.
• The valuation. Your lender values the home before it lends. If the valuation is below the price, you may need to find more money.
• The builder failing. If the builder becomes insolvent before completion, you need your deposit to be protected.

Each of these can be managed. The rest of this guide shows how.

The off-plan timeline

Reservation and exchange

When you reserve, you sign a reservation agreement. With a builder registered under the New Homes Quality Code, it must include the price and how long it is valid for, the fee and the refund terms, a cooling-off period of at least 14 days, and the date by which you must exchange. That date must normally be at least six weeks after you reserve unless you ask for an earlier one.

Before you exchange, for an off-plan home the builder must also give you the expected completion date, and a brochure or plan showing the size, specification, layout, plot position and which way the home faces. It must show any steep slopes in the garden and how boundaries and surfaces will be finished.

At exchange, you pay your deposit. The NHQB guide says this is usually 5% to 10% of the price. If you pull out after exchange, you are likely to lose it. Depending on the build stage, you may exchange with a fixed completion date or "on notice", where the date is set once the home is nearly ready. The contract should give the expected date the notice to complete will be served and the anticipated completion date.

The reservation to completion guide explains each document.

How your deposit is protected

Your deposit could sit with the builder for many months, so check how it is protected before you exchange.

Under the New Homes Quality Code, a registered builder must have adequate arrangements to protect your deposit, reservation fee and other payments. The Code gives these as examples:

• insuring the full contract deposit through the new home warranty
• holding the deposit, reservation fee and other payments in a separate client account that the builder cannot draw on until completion
• another legal arrangement that would let the builder repay you

The contract of sale must also explain how your deposit will be protected. If the contract is cancelled, the builder must refund your deposit and anything else due within 28 days.

Warranties can add protection. NHBC's Buildmark, for example, covers the period between exchange and completion, including loss of your deposit, or having to pay more to complete the build, if the builder becomes insolvent. Check your own warranty's terms and any limits. The warranties guide explains the cover.

Delays, long-stop dates and your right to cancel

Builds run late. What matters is what your contract says will happen when they do.

Under the Code, the contract of sale must clearly explain what happens if the home is not ready by the date the builder said, and set out when you can cancel. That might include an excessive or unreasonable delay in finishing the home and serving the notice to complete.

Many contracts do this with a long-stop date: a final date after which, if the home is still not ready, you can cancel and get your deposit back. Ask your solicitor:

• Is there a long-stop date, and when is it?
• What exactly happens if the builder misses it?
• Is there any compensation for delay?
• How will the builder keep you updated? Under the Code, it must explain how it will keep you informed about when the home is likely to be ready.

Plan your life around a moving date

• If you rent, avoid giving notice until the builder serves the notice to complete, or make sure your tenancy can run on.
• If you are selling, talk to your buyer and solicitor early about the timing, or ask whether the builder offers part exchange. See the part exchange guide.
• Book removals flexibly. The firm completion date usually comes only about two weeks ahead.

Mortgage offers that expire

The NHQB guide says a formal mortgage offer is usually valid for six months, and you must complete within that period to use it. If the home will not be finished in time, you may need to extend the offer or apply again. A new application means a new assessment of your finances and, possibly, a different rate and valuation.

Before you exchange:

• ask the builder for its best estimate of completion, and compare it with your offer's expiry date
• ask your lender, through a qualified, regulated mortgage adviser of your choosing, whether the offer can be extended for a new build and on what terms
• keep your finances steady until completion: lenders can recheck your circumstances
• remember that interest rates may have changed by the time you complete

The new-build mortgages guide explains how lenders treat new homes, valuations and incentives. The cash you need calculator shows the deposit, stamp duty and fees on a real home, less the builder's incentive, as an illustration, not advice.

Changes to your home

Builders may change the design, materials or specification as they build. The Code splits changes into two kinds.

A major change is one the builder is responsible for that significantly and substantially affects the size, appearance or value of the home, including the internal layout, compared with what you were shown in the reservation agreement or contract. The builder must tell you in writing. If you find it unacceptable, you can cancel the reservation or contract and get a full refund of your deposit, reservation fee and other payments, as long as you cancel within 14 days of receiving the written details. The builder cannot serve the notice to complete during those 14 days.

Smaller changes do not give you a right to cancel, but the builder must keep you informed, and you can still complain about snags.

If you have paid for extras or upgrades and then cancel, the builder must refund those payments less any costs it has already paid for them. If extra work you ask for will delay the build, get legal advice before agreeing to it.

Stamp duty on an off-plan home

You pay stamp duty when you complete, not when you exchange, on the price you pay. The return must be sent and the tax paid within 14 days of completion, and your solicitor usually does this for you.

Normally, the rates in force at completion apply, although tax changes sometimes include transitional rules for contracts already exchanged. In England and Northern Ireland, standard stamp duty is currently nil up to £125,000, and first-time buyers pay nothing up to £300,000 on homes up to £500,000. These figures were last checked against GOV.UK on 21 October 2026. On a £350,000 home, a home mover pays £7,500 and a first-time buyer £2,500. If rates change between exchange and completion, your bill changes too. The stamp duty calculator works out yours.

Before completion: the inspection

Once the builder serves the notice to complete, you have the right to inspect the home yourself, or appoint a suitably qualified inspector, before completion. The inspection uses the NHQB's standard pre-completion inspection checklist. The Code expects the notice period to be at least 14 calendar days, partly to leave time for it.

For an off-plan buyer, this is often the first time you see the finished home. Check it against your plans and specification as well as for snags. The builder must deal with problems that breach the warranty's technical standards, ideally before completion, or within 30 days if not. The snagging guide has a room-by-room checklist.

Your off-plan checklist

Before you reserve:

• check the builder is on the NHQB register, and note its registration date
• ask for the plans, specification, expected completion date and site plan in writing
• ask about tenure, service charges and estate charges
• have your deposit ready and an agreement in principle in hand

Before you exchange:

• confirm how your deposit is protected
• read the delay terms and any long-stop date with your solicitor
• check your mortgage offer's expiry date against the expected completion
• get any spoken promise written into the contract through your solicitor
• get every builder-stated incentive confirmed in writing

Before you complete:

• arrange buildings insurance from completion day
• book your pre-completion inspection
• check the list of incomplete work and the warranty documents the builder gives you

For every step from budget to keys, read how to buy a new build home.