Most buyers in England and Wales complete four to twelve weeks after receiving a mortgage offer. A straightforward chain-free purchase where both sides move quickly can wrap up in four to six weeks; add a property chain or a slow local authority and eight to twelve is more realistic. Your mortgage offer itself is usually valid for six months from the date it’s issued, so there’s normally a comfortable buffer, but the weeks between offer and completion are dominated by conveyancing work that can eat through that buffer faster than expected.
What Fills the Weeks Between Offer and Completion
The mortgage offer confirms the money is there. The conveyancing work confirms the property is worth buying with that money. Your solicitor handles several overlapping tasks during this phase, and a delay in any one of them can push the whole timeline back.
Property Searches
Your conveyancer orders searches covering local authority records, environmental risk, and water and drainage. The local authority search reveals planning permissions, building regulation compliance, and whether the property sits in a conservation area. The environmental search checks for flood risk and land contamination. The water and drainage search confirms mains connections. Together these cost roughly £250 to £450 and typically take two to four weeks to come back. Some local authorities are notoriously slower than others, and there’s nothing your solicitor can do to speed up a slow council.
Satisfying Mortgage Conditions
Your offer almost certainly comes with conditions that must be met before the lender will release funds. The most common are a satisfactory property valuation (which your lender usually arranges before issuing the offer), proof of buildings insurance from exchange, and confirmation of your deposit source. If the valuation flagged structural concerns or came in lower than expected, the lender may require those issues resolved before proceeding. Unresolved conditions are one of the most common reasons completion gets delayed.
Source of Funds
Anti-money laundering rules require your solicitor to verify where your deposit came from. Expect to provide three to six months of bank statements showing the money trail, whether the funds come from savings, investments, or a gifted deposit from family. If the money moved between accounts or arrived as a gift, your solicitor will want documentation for every transfer. Getting this paperwork together early saves time later.
Buildings Insurance
Your lender will require buildings insurance to be in place from the date of exchange, not completion. This catches some buyers off guard. You need cover before you’ve legally committed to the purchase, because exchange is the point at which risk in the property passes to you. Your solicitor needs a copy of the policy or confirmation from your insurer before they can proceed to exchange.
Exchange of Contracts
Exchange is the moment the purchase becomes legally binding. Before this point, either side can walk away without penalty, frustrating as that is. At exchange, your solicitor and the seller’s solicitor confirm by phone that both sides have signed identical contracts, and your solicitor transfers the deposit to the seller’s solicitor.
The deposit is typically ten percent of the purchase price, though this can be negotiated. The Standard Conditions of Sale set ten percent as the default, but buyers and sellers can agree in writing to a different figure, and five percent is common for first-time buyers stretching to afford the purchase. Whatever the amount, if you pull out after exchange, you forfeit the deposit. The seller faces equivalent liability if they withdraw.
Exchange also fixes the completion date. Most buyers agree on a completion date one to two weeks after exchange, though longer gaps are possible if someone in the chain needs extra time. From this point forward the timeline is locked.
Completion Day
On completion day your solicitor requests the mortgage funds from your lender and transfers the full purchase price to the seller’s solicitor via CHAPS, a same-day electronic payment system for large sums. Once the seller’s solicitor confirms receipt, they authorise the release of keys, usually through the estate agent. The standard expectation is that the seller vacates and the buyer gets access by 1pm, unless a different time was agreed at exchange. In a chain, this can slide later in the day as each transaction waits for the one below it to complete.
One cost worth budgeting for now rather than being surprised by later: Stamp Duty Land Tax must be paid within 14 days of completion, and your solicitor handles the payment and filing. Rates depend on the price and whether you qualify for first-time buyer relief, so check the current bands before you finalise your figures.1GOV.UK. Stamp Duty Land Tax – Residential Property Rates
What Slows Things Down
Property Chains
A property chain exists when your seller is also buying, and their seller is also buying, and so on. Every link must be ready to exchange and complete on the same dates, which means the slowest transaction dictates the pace for everyone. Research suggests roughly a third of buyers find themselves in a chain, and nearly half of those experience delays or collapses as a direct result. Chain-free purchases move significantly faster and carry less risk of falling through.
New Build Properties
Buying a new build introduces a variable that doesn’t exist in a standard resale: the property might not be finished yet. New build contracts typically include a long-stop date, often set around six months after the anticipated completion date, which acts as a final deadline for the developer to hand over the property. If the developer misses the long-stop date, you can cancel the contract and get your deposit back, or agree to extend. The gap between offer and completion on a new build can stretch well beyond the normal range if construction runs behind schedule.
Leasehold Properties
Buying a leasehold flat rather than a freehold house adds extra steps. Your solicitor needs to obtain a management pack from the freeholder or managing agent, detailing service charges, ground rent, building insurance, planned maintenance, and the financial health of the building. These packs typically cost £200 to £500 and take two to four weeks to arrive, sometimes longer if the managing agent is unresponsive. Freehold purchases skip this step entirely, which is one reason houses tend to complete faster than flats.
What Happens If Your Mortgage Offer Expires
If completion drags past the offer’s expiry date, you’ll generally need to reapply for the mortgage. That means fresh credit checks, updated affordability assessments, and a new round of paperwork. The bigger risk is that rates or lending criteria may have shifted in the months since your original application, and there’s no guarantee you’ll get the same deal. Many lenders will grant an extension if your circumstances haven’t changed and the delay was clearly outside your control, so contact your lender well before the expiry date if completion is running behind. Your solicitor should be tracking this, but it’s worth monitoring yourself. Losing a mortgage offer deep into a transaction is one of the more stressful things that can happen to a buyer.