How to challenge a mortgage down valuation

A down valuation is when the surveyor acting for a mortgage company values the property for less than the price the buyer has agreed to pay¹. The lender will only lend against its own valuation, so the shortfall has to come from somewhere: a bigger deposit, a lower purchase price, or a different property.

The gap can be large. Buying a £250,000 property with a £25,000 deposit needs a 90% mortgage of £225,000; if the lender's surveyor decides the property is actually worth £200,000, 90% is £180,000, giving £205,000 in total and a £45,000 shortfall². That is the arithmetic a buyer is left to solve.

A down valuation can be challenged, but accepting a challenge is at the discretion of the lender². The realistic routes are: put forward better evidence, use the valuation to renegotiate with the seller, wait for remedial work to be done and ask for a revaluation, or, as a last resort, apply to a lender that uses a different surveyor².

What a down valuation is and why it happens

A mortgage valuation is a valuation commissioned by your lender to assess whether the house is worth what you are planning to pay for it¹. It is not a survey for the buyer. The lender instructs the valuer, and the borrower generally pays for it as part of the mortgage application⁴. It should be carried out by a qualified surveyor accredited by the Royal Institution of Chartered Surveyors⁴.

The surveyor may also provide the lender with a minimum reinstatement value, which is the amount you would need to rebuild the property from the ground up, useful when getting buildings insurance cover³. That figure is separate from the market valuation and does not affect how much the lender will advance.

Valuations come in low for reasons that have nothing to do with the buyer. The surveyor may find fewer comparable sales than the estate agent used, may take a more cautious view of a falling or flat market, or may judge that the property has features that narrow the pool of buyers. Where the property needs work, the surveyor may value it as it stands rather than as it would be once repaired.

If the valuation is low because remedial work is needed, a revaluation following the completion of the work may resolve the issue⁵. That is a different situation from a straightforward disagreement about market value, and it usually has a clearer route to a fix.

How a down valuation leaves a gap in your deposit

The lender's loan is calculated as a percentage of the valuation, not of the price. So a down valuation does two things at once: it reduces the maximum the lender will advance, and it leaves the buyer to find the difference in cash.

In the worked example, the buyer agreed to pay £250,000 with a £25,000 deposit and needed a 90% mortgage of £225,000. Once the property is valued at £200,000, 90% is £180,000, giving £205,000 in total and a £45,000 shortfall². The buyer's own money has not changed; the lender's maximum has.

There is a second risk. By paying above the valuation figure you are increasing your risk of negative equity, which is when your borrowings exceed the market value⁶. Negative equity is when your home is worth less than what you owe⁷. It matters most if you need to sell, because the sale proceeds may not clear the mortgage.

The same principle appears in shared equity schemes. In one official example, the applicant would personally contribute £15,000, made up of 5% of the valuation as a deposit plus the £10,000 above valuation⁸. The buyer is effectively funding the gap between what a lender will recognise and what the seller will accept.

Challenging the valuation: evidence the lender needs

You may be able to challenge the valuation if you have robust evidence, but accepting a challenge is at the discretion of the lender². Customers may appeal against down valuations, but strong evidence will be needed to challenge such as recent local sales data⁹.

The evidence that carries weight is evidence about the property and its immediate market:

• Recent sale prices for comparable properties in the area³
• At least 6 comparable properties and sale prices from the last year if the property has increased or decreased in value, in the case of a Help to Buy equity loan valuation¹⁰
• Proof the property is on the market at a reasonable price¹¹
• A sale brochure and energy performance certificate¹¹
• Permission for the lender to speak to your estate agent and conveyancer¹¹

A valuation report can be rejected if it does not follow the criteria, or is too high or too low compared to similar properties¹⁰. That cuts both ways: the same standard of comparables that a scheme applies to a buyer's own report is the standard a challenge is measured against.

Renegotiate or challenge: using the valuation with the seller

If you receive a down valuation on the property you want to buy, the first thing to do is try and renegotiate the sale price with the seller; a down valuation is a strong bargaining tool². The lender's figure is independent of both buyer and seller, which is what gives it weight in the conversation.

The options if the valuation is not overturned are set out plainly: dispute the valuation by providing sales evidence of similar properties in the area, reduce the amount you wish to borrow, or return to the vendor with a revised offer based on the lender's valuation¹³.

Renegotiation is not guaranteed to work. A seller may have their own reasons for holding the price, may have another buyer waiting, or may simply refuse. Where a sale does fall through, the buyer has usually spent money on a valuation and legal work with nothing to show for it, which is why the decision to walk away is a financial one as much as a negotiating one.

If you are hoping to sell your home, it is possible to check what property value your existing lender has on file². That gives a sense of the figure a future buyer's lender may be working from before the property goes to market.

When remedial work caused the down valuation

Where the down valuation is due to a need for remedial works, a revaluation following the completion of the work may resolve the issue⁵. This is the most straightforward version of the problem: the surveyor has priced the property as it is, not as it will be.

The practical sequence is to get the work done, keep the paperwork, and ask the lender to look again. A revaluation is a fresh assessment, and the lender's decision on the first figure does not bind it on the second.

There is a wider lesson about how these processes are run. In an official evaluation of the Help to Buy scheme, the negative views about the redemption process were driven by customers needing to manage multiple stakeholders, short valuation periods and poor communication from the loan administrator¹⁴. Where a valuation sits inside a scheme with its own administrator, the buyer is often dealing with more than one organisation at once, and timelines matter.

If a valuation dispute turns into a formal complaint, the Financial Ombudsman Service handles complaints about mortgage valuations and surveys⁴. Complaints about a firm's conduct are separate from a disagreement about the number itself.

Trying another lender as a last resort

Your last resort might be to try an alternative lender that uses a different independent surveyor, which may give a valuation closer to the sale price². Different lenders use different surveyors, and a second opinion can land higher.

It is a last resort for good reasons. A new application means new checks and potentially new fees, and the second valuation could come in at the same figure or lower. Remortgaging to another lender at the end of your term is a risky strategy because mortgage criteria changes frequently¹⁵. The same caution applies to switching lender mid-purchase to chase a valuation.

There is also a timing problem. A seller is not obliged to wait while a second lender is approached, and a chain can collapse in the meantime. Where a buyer has already exchanged contracts, the options narrow considerably.

If the numbers no longer work, the honest options are to find more deposit, borrow less by agreeing a lower price, or step away. Where a buyer is already struggling with mortgage payments, lenders are expected to consider whether further support is needed where a customer applying for a variation has a payment shortfall, or indicates that they are at risk of falling into payment shortfall¹⁶. Lenders may also reduce or stop charging interest on arrears¹⁷. Free, impartial help is available from MoneyHelper and from debt advice charities.