When Do House Sales Fall Through? The Timing Data

Most sellers brace for a late collapse. The data says the opposite: 38% of fall-throughs happen within four weeks of a sale being agreed. Here is the risk profile week by week.

Propelr Editorial Team10 min read

What you need to know

TwentyCi data shows 38% of all fall-throughs happen within the first four weeks after a sale is agreed, and nearly 16% within the first two. Risk is concentrated early, not late, because the buyer has committed nothing, the survey lands in that window, and little visible progress is being made while searches are pending.

  1. 38% of fall-throughs happen in the first four weeks after a sale is agreed; nearly 16% in the first two.
  2. Risk is front-loaded because the buyer has committed no money and the survey lands in weeks two to four.
  3. The mortgage offer being formally issued is the point at which risk drops materially, typically week six to ten.
  4. After exchange of contracts a withdrawal is a breach — deposit forfeited and penalty interest at the contract rate.
  5. Having legal work underway before an offer converts the riskiest weeks from silence into visible progress.

Ask a seller when they expect their sale might collapse and most will say near the end — a last-minute problem, a chain breaking at week eleven, a buyer getting cold feet before exchange. It is a reasonable intuition and it is wrong.

According to TwentyCi, 38% of all fall-throughs happen within the first four weeks after a sale is agreed, with the first two weeks alone accounting for nearly 16% of collapsed deals. The most dangerous period is the one that feels safest.

The risk profile, week by week

PeriodWhat is happeningRisk level
Weeks 1–2Memorandum of sale issued, solicitors instructed, ID checks. Buyer has spent almost nothing.Very high (~16% of all fall-throughs)
Weeks 3–4Survey carried out and reported. Searches ordered. Contract pack issued.Very high (38% cumulative)
Weeks 5–8Searches pending, enquiries raised and answered, mortgage valuation and offer.Moderate, falling once the offer is issued
Weeks 9–12Enquiries resolved, completion date agreed, contracts approved.Lower, but chain risk persists
After exchangeContract legally binding. Deposit at risk.Very low

Why the early weeks are so dangerous

1. The buyer has committed nothing

In the first fortnight a buyer has typically spent a few hundred pounds at most. Walking away costs them almost nothing beyond the time. The asymmetry is stark: you have taken your property off the market, told your onward seller you are proceeding, and possibly stopped viewings entirely.

This is precisely the gap the government intends to close with binding conditional contracts, which would commit both parties shortly after an offer with financial penalties for withdrawing without a legitimate reason.

2. The survey lands here

Buyer surveys are typically carried out in weeks two to four. Survey issues are the single largest cause of collapse in the UK, at 37.5% of all fall-throughs. That means the largest single risk factor in the entire transaction arrives inside the window where risk is already highest.

It is also the most controllable. See how survey issues cause fall-throughs and whether a pre-sale survey is worth it.

3. Nothing visible is happening

Searches take two to eight weeks depending on the council. During that time a typical buyer receives no news at all. A buyer with lingering doubts, or one who has just seen another property come to market, has weeks of silence in which to reconsider — and no evidence that they would lose anything by doing so.

When risk actually drops

Two moments matter more than the calendar:

  • The mortgage offer is formally issued.Until this point the buyer's finance is not secured. A declined application, a down-valuation, or a lender changing its criteria are all live risks. Once the offer is in hand, a major category of failure is closed off.
  • Exchange of contracts. The transaction becomes legally binding. A buyer who then walks away forfeits their deposit — usually 10% of the purchase price — and is liable for penalty interest at the contract rate, typically 4% above the Bank of England base rate, currently 3.75%. See what happens if completion is delayed.

What to do in each window

Before you accept an offer

This is where the leverage is. Instruct a conveyancer and get the legal pack, property forms and searches underway before you have a buyer. It converts the riskiest four weeks from a dead zone into a period of visible progress, and it means the survey is not the only thing happening. See when to instruct a solicitor before listing.

Weeks 1–4

  • Return your TA6 and TA10 forms within days, not weeks — they are the most common early bottleneck.
  • Make the property available for the survey immediately. Delay here pushes the single largest risk factor further into the transaction.
  • Ask your agent for a weekly update to the buyer even when there is nothing to report. Silence is what kills deals in this window.
  • Prepare for the survey result before you get it. Know your roof, your damp and your electrics.

Weeks 5–8

  • Answer enquiries the day they arrive. Rounds of enquiries are sequential, so a three-day delay on your side becomes a three-week delay overall.
  • Confirm the buyer's mortgage offer has been issued, not just applied for.
  • If you are in a chain, ask your agent to confirm the status of every link, not just your own buyer.

Weeks 9 to exchange

  • Push for a firm exchange date rather than an open-ended “soon”.
  • Resolve any retention or repair negotiation quickly — a stalled negotiation at this stage is where late collapses cluster.
  • Keep the buyer engaged. A buyer who has been waiting eleven weeks is fragile even when everything is technically fine.

Sources and further reading

  • TwentyCi— Property and Homemover Report, timing of fall-throughs
  • Quick Move Now— Quarterly fall-through tracker and causes analysis, 2026
  • MHCLG— Home buying and selling reform roadmap, June 2026 (gov.uk)
  • Law Society— Standard Conditions of Sale and the conveyancing protocol (lawsociety.org.uk)

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Frequently asked questions

When are house sales most likely to fall through?

In the first four weeks after a sale is agreed. TwentyCi data shows 38% of all fall-throughs happen in that window, with the first two weeks alone accounting for nearly 16% of collapsed deals. This is counterintuitive — most sellers assume risk builds as the transaction drags on — but the early period is when buyers are least committed and least informed, and when the least visible progress is being made.

Can a sale fall through after exchange of contracts?

It is rare but possible. After exchange the contract is legally binding in England and Wales, so a party who walks away is in breach and faces losing their deposit, paying penalty interest at the contract rate, and potentially being sued for the seller's losses on a resale. Sales that fail after exchange usually do so because a party cannot complete rather than will not — a lender withdrawing funds on the day, or a death in the chain. Before exchange, either party can withdraw at no cost.

How long after an offer is accepted is a sale safe?

It is never fully safe until exchange, but the risk profile improves substantially once searches are back, enquiries are answered and the buyer's mortgage offer is formally issued. In practice that is typically six to ten weeks in. The critical threshold is the mortgage offer: until it is issued the buyer's finance is not secured, and a declined or reduced offer at that point is one of the most common late-stage causes of collapse.

Why do sales fall through so early?

Three reasons compound in the first month. The buyer has committed almost nothing financially, so walking away is cheap. The survey usually lands in weeks two to four, and survey issues are the single largest cause of collapse at 37.5%. And almost nothing visible happens while searches are pending, so a buyer with second thoughts has weeks of silence in which to act on them.

Does a longer chain change when sales fall through?

Yes. In a chain your transaction is exposed to every other link, so the risk is spread across the whole timeline rather than concentrated early. A chain of four can fail at week ten because someone at the far end lost their buyer. Chains also stretch the timeline, and a longer transaction gives more opportunity for circumstances to change. This is why chain-free buyers command a genuine premium beyond the headline offer.

What is the single best thing I can do to reduce early risk?

Have the legal work underway before you accept an offer. If your contract pack, property forms and searches are already prepared, the first four weeks contain visible progress instead of silence, the survey lands against a backdrop of momentum rather than uncertainty, and the buyer has evidence that the transaction is moving. That directly attacks the window where 38% of fall-throughs occur.

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