Part Exchange Explained: Selling Your House to a Builder (2026)

By Lisa Hayes · 12 November 2026

Part exchange is when a housebuilder buys your current home so you can buy one of its new builds, with both sales completing on the same day and no chain. You trade some of your sale price for certainty and speed: the builder's offer is based on independent valuations, but it is pitched at what your home would fetch in a quick sale, not the best price a patient seller might get. For the right person it is brilliant. For the wrong person it is an expensive way to buy a house you might not have chosen.

I'm Lisa Hayes, and I spend my working life comparing quick-sale routes for UK homeowners. Part exchange is the one people ask me about most when a shiny show home has already stolen their heart. So here is everything: how it works, what the big builders actually require, what the rules say, how the maths stacks up against the alternatives, and the questions you should ask before you sign anything.

What is part exchange, in plain English?

You find a new-build home you want. The developer agrees to buy your existing home from you as part of the deal. On completion day, they pay you for your old house (usually by netting it off against the price of the new one), you hand over the keys, and you collect the keys to your new place. There is no buyer of your own to find, no chain beneath you, and no viewings with strangers poking around your airing cupboard.

The builder then sells your old home on, usually through a local estate agent. That is the bit people forget. The developer is not a charity and not a landlord. It takes your house so that it can sell its own, and it prices your house so that reselling it carries little risk. That's the trade.

Part exchange is not the same as a cash house buyer, although the experience can feel similar. A cash house buyer buys your home with no strings attached. A part-exchange builder only buys it if you buy theirs. Your house is, in effect, a bargaining chip in a new-build sale.

How does part exchange work, step by step?

The detail varies by builder, but the pattern across Barratt, Persimmon, Redrow and Gleeson is broadly the same:

1. Choose a plot and check eligibility. The sales adviser checks your home's rough value against the new home's price, your tenure (freehold or leasehold, and how long the lease runs), and condition.
2. Reserve the new home. You sign a Reservation Agreement and usually pay a reservation fee. Barratt's terms require the reservation and fee before the part-exchange application goes ahead.
3. Valuations. The builder sends independent valuers, typically local estate agents and sometimes a RICS surveyor, to your home. Barratt asks for access within three working days of reserving. Most builders use at least two valuations.
4. The offer. You receive a figure. Redrow says plainly that the first offer is often given verbally. You then have a short window to accept: Barratt's terms give you two working days, and an unaccepted offer cancels the reservation.
5. Surveys and conveyancing. Your solicitor handles both your sale to the builder and your purchase. Expect the builder to want gas and electrical certificates and an EPC. Barratt's terms also set a 42-day exchange requirement for your solicitor.
6. Exchange and completion together. Both transactions complete on the same day. You must give vacant possession, meaning you are out, with your belongings, by completion.

Who can use part exchange? The eligibility rules

This is where many people fall at the first hurdle. Part exchange is built for trading up. The builder wants the house it takes from you to be a smaller, easier-to-sell asset than the one it's selling you.

Two quick translations. Barratt's 80% rule means the new home must cost at least 25% more than your current one. Persimmon's 70% rule means it must cost roughly 43% more. Persimmon does say to speak to its sales team if the gap is smaller, so treat these as starting points rather than walls.

Things that commonly cause a "no": a short lease, a non-standard construction type, serious structural issues, a home that is hard to mortgage, or anything that makes resale slow. Persimmon's 105% promotion from March 2026 is instructive: homes more than ten years old needed a satisfactory HomeBuyer report, and the builder kept "absolute discretion" over whether to buy. If your home has a known problem, part exchange is unlikely to be the answer. A specialist route is a better fit, and our guide to selling an "unsellable" house covers those.

Can you part exchange if you are downsizing?

Usually not, at least not under a standard part-exchange scheme. The value rules above point firmly the other way. If your current home is worth more than the new one, the builder would be paying out money and taking on a bigger, slower asset. That's precisely what it is trying to avoid.

Downsizers buying a new build are more likely to be offered an assisted-move scheme instead (more on that below), or to be asked to sell on the open market. Retirement developers sometimes run their own variations. If you're downsizing, compare those offers against a straightforward fast sale of your current home, because you will have equity to release and every percentage point matters more.

How much will a builder offer for my house?

Here's the honest answer: less than the best price you could achieve with time, but how much less depends on your home and your local market. I won't give you a magic percentage, because the builders don't publish one and anybody who quotes a single figure is guessing.

What the builders do publish tells you how the figure is reached:

• Barratt makes a "fair value" offer based on a presumed sale within 8 to 10 weeks, using two independent valuations and a RICS survey.
• Persimmon says its offers are based on independent valuations and "may be slightly below open market value".
• Gleeson describes its offer as "based on fair market value".
• Persimmon's 105% promotion paid 105% of a "PX Property Valuation Price", defined as the "baseline risk value price assessed by an independent valuer". As the wording suggests, that baseline is a cautious figure, so 105% of it is not the same as 105% of your asking price. That offer ran for one week in March 2026 on selected plots and has expired, but the structure is typical of how these promotions are framed.

The key phrase is that 8-to-10-week presumed sale. A home priced to sell in two months is priced keenly. If local homes like yours usually take four or five months to find a buyer, the gap between that and a quick-sale price can be meaningful. If your street sells in a fortnight, the gap may be small.

What does the New Homes Quality Code say about part exchange?

Most big builders are registered with the New Homes Quality Board and must follow its New Homes Quality Code. Version 2, dated March 2026, has a section written specifically for this: section 1.4, "Part-exchange and assisted-move schemes". It says the terms "must be clear, fair and not misleading, and must not be used to pressurise the customer into a sale", and the developer must give you enough time to consider the information.

The builder must explain, in plain language:

1. the full terms and conditions, including any leasehold or tenure conditions, the price offered and how long the offer is valid;
2. how the fair market valuation was decided, which must be independent and come from more than one suitably qualified source;
3. any deductions applied to the market valuation;
4. how you qualify for the scheme;
5. the date you must accept the offer by, and what happens if you don't;
6. the expected completion dates for both transactions, and what happens if they don't fall on the same day.

Point 3 is the one I'd underline twice. If the builder's valuers said £250,000 and you're offered £237,500, the Code says you are entitled to know how that £12,500 was arrived at. Ask for it in writing.

The Code also bans high-pressure selling (section 1.3), including suggesting other people are interested or that the price will soon rise when that isn't true, and "offering a financial incentive in return for an immediate decision". It requires a 14-day cooling-off period on Reservation Agreements (section 2.3), with a full refund of the reservation fee if you cancel in that window, and it says the builder must tell you to get independent legal advice (section 1.7). That last point matters: you can use your own solicitor, not just the one on the sales office's list.

If a builder breaches the Code, you complain to the builder first and can then escalate to the New Homes Ombudsman Service.

What does part exchange cost you, and what does it save?

The headline saving is estate agent fees. Our estate agent fees guide covers typical costs, but on an average home that is a four-figure sum. You also avoid the cost of a chain collapsing: lost survey and legal fees, a lapsed mortgage offer, months of uncertainty.

What you still pay is easy to overlook:

• Your own legal fees for both the sale and the purchase. Persimmon and Gleeson both say these sit with you.
• Agent fees you've already run up. If your home was already on the market, Barratt's terms say you pay any fees or commission owed to that agent. Check your agency agreement for a tie-in or withdrawal fee first.
• Certificates and an EPC if you don't have them. Gleeson specifically says you pay for the EPC.
• Stamp Duty on the new home, calculated in the normal way on the price you pay for it. Part exchange does not reduce it.
• A deposit on the new home. Barratt notes that a deposit of typically 10–20% is still needed, often funded from your equity.
• The discount between your home's open-market value and the builder's offer. This is the big one, and it's invisible unless you've done your homework.

Is part exchange worth it? The pros and cons

My view, plainly: part exchange is worth it when you've already decided on a specific new build on its merits, your current home is mid-market and easy to value, and certainty matters more to you than the last few thousand pounds. It's poor value when the scheme is the reason you're buying a new build at all.

The mistake almost everyone makes: looking at only one price

When people judge a part-exchange deal, they focus on what the builder will pay for their old home. Fair enough. But there are two prices in the deal, and the builder controls both.

Picture a hypothetical. You're offered £10,000 less than you'd hoped for your current home, but the builder throws in carpets and a contribution to moving costs. Meanwhile, the new home's list price is firm. Compare that with a buyer who sells on the open market, turns up as "chain-free, mortgage agreed" and negotiates £15,000 off the same new home because the site has unsold plots near the end of the financial year. The second buyer is ahead, even before you count the agent fees they paid.

That doesn't mean the second route always wins. It means you should negotiate on the whole package: the price of the new home, the part-exchange figure, and the incentives. Ask the sales adviser directly what the new home would cost without part exchange. If there's a better price for a buyer who doesn't need it, you've learned how much the scheme is really costing you.

Also bear in mind that new builds often carry what's sometimes called a new-build premium, and some lose value in the first few years. If you might sell again soon, read our guide to reselling a new-build house before you commit.

Part exchange vs assisted move vs cash buyer vs open market

Part exchange is one of four realistic routes when you want to buy a new build. Here's how they compare:

How does an assisted move differ from part exchange?

With an assisted move, the builder doesn't buy your home. It helps you sell it. Barratt's Movemaker scheme, for example, agrees an asking price after two independent valuations, instructs an estate agent, and covers the agent's fees. You keep the upside of an open-market price, but you still need a buyer, and you still carry chain risk. Assisted moves suit people whose homes would sell well but who want the builder's help and fees paid. They are also open to some people whose homes fall outside part-exchange value rules, so ask.

Is a cash buyer better than part exchange?

Sometimes. A cash buyer's offer is independent of which home you buy next, so you keep your freedom: you can buy a resale home, a different builder's home, or rent while you decide. Their prices are often below market value too, and the industry has its share of firms that offer high and then cut the price days before completion. Our guide to how far below market value "we buy any house" firms pay explains the gap, and our comparison of the best house buying companies shows which ones have a track record of paying what they offer.

The useful move is to get a cash offer alongside the part-exchange offer. If they are close, part exchange may win on convenience. If the cash offer is clearly higher, you have negotiating ammunition with the builder.

What about selling on the open market and buying a new build chain-free?

If your home is desirable and your local market is moving, this is often the highest-value route. The risk is timing. Builders don't hold plots forever, and Reservation Agreements have time limits. Our guide to selling and buying at the same time covers the juggling act.

What does a part exchange guarantee mean?

Some builders offer a twist: a guarantee that if they resell your old home for more than they paid you, they'll pass some of the difference back. Barratt's Part Exchange Guarantee is the clearest published example, and it's worth understanding the small print because it is less generous than the headline suggests.

• You get a "balancing payment" equal to the resale price minus the offer, less reasonable administration fees, including estate agent fees.
• Barratt's own worked example: offer £200,000, resale £210,000, agent fees £3,300, payment to you £6,700.
• The payment only applies if the resale completes within nine months of your new-home purchase completing.
• Barratt can reduce the marketing price by 2% every six weeks, and the marketing price cannot exceed the open-market values in the two valuations.
• If a buyer offers at least 98% of the marketing price, Barratt decides whether to accept.

So the guarantee is genuinely useful if your home is undervalued in a quick-sale offer and then sells quickly and well. But notice that the agent fees you thought you were saving come back out of your balancing payment. It is a partial safety net, not a promise of full market value.

Can you part exchange a flat, a leasehold home or a home with a mortgage?

A home with a mortgage: yes. That's the norm. Your existing mortgage is redeemed from the builder's payment on completion, just as with any sale. Check for early repayment charges first, and ask your lender for a redemption statement so you know exactly what will be repaid.

A leasehold flat: possibly, but expect tighter scrutiny. Persimmon wants at least 80 years left on the lease. Ground rent terms, service charges and any cladding or EWS1 questions can all count against you because they slow the builder's resale. If your flat has complications, you'll probably get a better result from a specialist route: see selling a flat fast.

A tenanted property: generally no. Part exchange requires vacant possession and is typically for your main residence only. Barratt's terms exclude buy-to-let properties outright. Landlords will need a different route, such as an investor buyer who will take the tenancy on.

An inherited property: rarely. You have to be buying the new home to live in, and most schemes exclude anything that isn't your main residence. Executors are usually better served by a normal sale or a vetted cash buyer.

Can you use part exchange with Help to Buy, shared ownership or other schemes?

The government's Help to Buy equity loan for new builds in England closed to new applications in 2022, so it's no longer a factor for new purchases. If you're selling a Help to Buy home, you'll need to repay the equity loan from the sale, which the builder's offer must cover.

Beyond that, check exclusions carefully. Persimmon's 105% terms excluded buyers using buy-to-let mortgages, discount-market schemes, shared ownership or shared equity, corporate buyers, and anyone exempt from Stamp Duty. Barratt's Part Exchange Guarantee can't be combined with its other offers. Builders often make you choose between part exchange and a cash incentive such as deposit or stamp duty contributions, so ask which is worth more to you in cash terms.

What happens if I turn down the part-exchange offer?

You're entitled to say no. Redrow puts it plainly: "you don't have to accept the offer." What happens next depends on the builder's terms. Under Barratt's Part Exchange Guarantee terms, an unaccepted offer cancels the reservation. Elsewhere you may be able to keep the reservation and sell your home another way, perhaps through an assisted move.

Remember the Code's 14-day cooling-off period on Reservation Agreements. If you cancel within it, you're entitled to a full refund of the reservation fee. After that, the agreement can set out deductions, so read that section before you pay.

You can also negotiate. A polite, evidence-based reply works far better than "that's too low". Send the builder your own agent valuations and two or three recent comparable sales, and ask them to explain the deductions they've applied, which section 1.4 of the Code requires them to do anyway.

How long does part exchange take?

Much of the timetable is driven by the new home, not the old one. If you're buying off-plan, you might wait months for build completion, and your part-exchange completion simply waits with it. If you're buying a finished home, the process can run broadly to the timetable of a normal purchase without the chain delays.

Barratt's terms give a sense of the pace once things are moving: valuer access within three working days, two working days to accept, and a 42-day exchange requirement for your solicitor. The Code says exchange shouldn't be less than six weeks after reservation unless you ask for an earlier date.

• 3 working daysto give Barratt's valuers access
• 2 working daysto accept Barratt's offer
• 14 dayscooling-off on any NHQC reservation
• 8–10 weekspresumed resale period behind the offer

Questions to ask the sales adviser before you reserve

Print these. Seriously. Sales offices are pleasant places designed to make you feel at home, and that's exactly when people forget to ask the awkward questions.

1. What is the price of this plot without part exchange, and what incentives would I get instead?
2. Who are the valuers, and can I see both valuations in full?
3. What deductions have you applied to the valuations, and why?
4. How long is the offer valid, and what happens to my reservation if I decline?
5. What is the reservation fee, what is deducted if I cancel after the 14-day cooling-off period, and is the price fixed for the life of the reservation?
6. When is the new home expected to complete, and what happens to my sale if the build is delayed?
7. Will you cover the estate agent fees in full, and do I owe anything to my current agent?
8. Is there any guarantee or top-up if you resell my home for more than you paid?

Common part exchange mistakes

Falling for the plot before checking the numbers. The show home is staged to perfection. Do your valuation homework first, then visit.

Letting the builder's solicitor do everything without questions. You're entitled to choose your own. The Code says builders cannot offer incentives when recommending a professional adviser, and can't make the sale depend on using a particular one.

Forgetting your existing agent's contract. If you've signed a sole agency agreement, withdrawing may cost you, and Barratt's terms make clear that's your bill. Read the notice period and any tie-in clause before you reserve.

Comparing the part-exchange offer to Rightmove asking prices. Asking prices aren't sold prices. Use HM Land Registry sold-price data for your street.

Treating speed as free. Certainty has a price. That price can be well worth paying, but you should know what it is.

Is part exchange the right choice for you?

Part exchange is a good tool used for the right job. If you've found a new build you'd buy anyway, your home is a straightforward, mid-market property, and the thought of another collapsed chain makes you feel ill, it can be the calmest move you ever make. Go in with your own valuations, ask the builder to show its workings as the Code requires, and negotiate the whole package rather than one number.

If you're not wedded to a particular new build, or your home doesn't fit the value rules, you've got more freedom than the sales office might suggest. A vetted cash buyer or a well-run open-market sale may leave you with more money and more choice about where you live next.

Either way, the smartest thing you can do is compare before you commit. Get your free valuation and compare offers from vetted buyers, then put those figures next to the builder's. If part exchange still wins, you'll sign knowing it was the right call.