Bridging for Unmortgageable Properties: the deals banks won't touch

A property is unmortgageable when a mainstream lender's valuer will not accept it as security. That is a narrower thing than most people assume. It does not mean the property is worthless, or unsafe, or a bad buy. It usually means it fails one specific test, often a test with nothing to do with the structure, and a great many of those failures are fixable in a matter of weeks.

This is the clearest reason bridging finance exists. High street lenders fund homes people can move into on completion, and their criteria are written to exclude anything that might not sell easily if they had to repossess it. Short-term lenders look at the same property and ask a different question: what will it be worth when it is finished, and can this borrower get there. That gap is where most refurbishment profit is made.

So this page sets out what actually makes a lender say no, which of those problems can be solved and which cannot, what it costs to fix them, and which properties you should walk away from.

What makes a lender say no

The list is longer than the obvious ones, and the reasons vary.

The property is not habitable

• No kitchen or no bathroom. The most common reason by a distance, and one of the cheapest to fix. Most lenders want a functioning kitchen and at least one working bathroom. A house stripped back for a refurbishment fails on this alone even if it is structurally perfect
• No working services. No mains water, no electricity supply, no heating, or a system disconnected and uncertified
• Derelict or long-term vacant. Extended vacancy raises both condition and insurance questions
• Fire or flood damage, until repaired and certified
• A property mid-conversion, where work has started and then stopped

Structural and construction

• Structural movement or subsidence, whether historic or active. Historic and stabilised is a very different conversation from ongoing
• Non-standard construction, a broad category covering concrete and PRC types, steel frame, timber frame without a brick outer skin, single skin brickwork, cob, post-war prefabricated types and high alumina cement. Lender appetite here varies enormously
• Defective premises. Certain PRC types are formally designated defective under the Housing Act, which narrows the lender list sharply unless the property has been repaired to an approved scheme with the paperwork to prove it
• Mundic block, specific to Cornwall and parts of Devon, where the test result decides everything
• RAAC, reinforced autoclaved aerated concrete, which has gone from obscure to mainstream knowledge and is treated seriously
• Roof structure problems, including spreading, inadequate support and failed repairs
• Japanese knotweed and other invasive species
• Spray foam insulation in the roof space
• Serious damp, dry rot or wet rot, where a specialist report is needed
• Asbestos, depending on type, location and condition

Title, tenure and legal

• Short lease. Most lenders want a minimum unexpired term, commonly 70 to 85 years at completion, and some want considerably more. Below around 70 years the field narrows fast. Below 60 it is very small
• Absent freeholder, which stops the lease being extended by the normal route
• Flying freehold or creeping freehold above a threshold proportion of the floor area
• Agricultural occupancy conditions, which restrict who may live in the property and sharply reduce both value and lender appetite
• Restrictive covenants preventing use, alteration or sale
• Unregistered title, or title defects such as missing rights of access
• Overage or clawback provisions
• Possessory title rather than absolute
• Tenants in situ on a residential purchase, or a sitting tenant on a regulated tenancy
• Section 106 restrictions or shared ownership complications

Fire safety and cladding

• Flats in buildings with cladding issues, where the lender wants evidence about the external wall system before lending. The position has improved a lot from the worst period, but a building without the right paperwork can still be unmortgageable
• Missing or unsatisfactory external wall assessments
• Inadequate means of escape, particularly in converted flats and HMOs

Location and use

• A flat above or next to commercial premises, particularly where the commercial use is a hot food takeaway, a pub, a launderette or anything else lenders think affects saleability
• Property with a trading element, including bed and breakfasts, pubs with living accommodation, and shops with flats above
• Ex-local authority flats in blocks above a certain height, or with a low proportion of private ownership
• Property in or next to a high risk flood zone, where insurance cannot be obtained
• Proximity to mining, landfill or contamination
• No road access, or access over land somebody else owns

Paperwork and process

• No EPC, or an EPC below the required rating. For a property you intend to let, the minimum standard matters
• Missing building regulations or planning consents for past work
• No warranty on a new build, or a warranty from a provider the lender does not accept
• Unsatisfactory or absent gas and electrical certification
• A property bought at auction inside six months, which is covered below and is a policy issue rather than a property issue

Value and size

• Below a lender's minimum property value, commonly £50,000 to £100,000 on the mainstream and considerably higher with some specialist lenders
• Studio flats below a minimum floor area, often 30 square metres
• Very large or very unusual properties where the valuer cannot find comparables

What can be fixed, and what cannot

This is the most useful distinction on the page, because people routinely spend money fixing the wrong thing. Somebody who spends £18,000 on a new kitchen and bathroom to make a flat mortgageable has wasted most of it if the real problem was a 58 year lease.

The pattern is worth noticing. Condition problems are nearly always fixable and usually cheap. Title problems are usually fixable but slow. Construction and location problems are generally permanent. Before you spend anything, work out which category you are in.

What the valuer actually writes

People rarely see the valuation report, which is why they do not understand what they are up against. The lender does not usually say "unmortgageable". The report says one of these things, and the lender acts on it.

• "Not suitable security for mortgage purposes." The outright refusal. The valuer has decided the property cannot support lending as it stands
• "Nil valuation." Not that the property is worthless, but that the valuer will not put a figure on it for lending purposes
• "Property is not currently habitable" or "no kitchen or bathroom facilities present." Usually the easiest to solve
• "Essential repairs required" with a retention of a stated sum. More on this below, because it is widely misunderstood
• "Recommend a specialist structural engineer's report." The valuer has seen cracking or movement and will not give an opinion without an expert. The report may clear it entirely
• "Recommend a timber and damp report by a suitably qualified specialist."
• "Recommend an invasive weed specialist report." The knotweed trigger
• "Evidence of historic structural movement, monitoring recommended." Monitoring usually means twelve months of readings, which no purchase timetable survives
• "Property of non-standard construction, limited lender appetite, marketability may be restricted."
• "Value subject to a satisfactory external wall assessment."
• "Unexpired lease term insufficient for lending purposes."
• "Limited demand" or "restricted marketability." The valuer's way of saying the property would be hard to sell on repossession, which is the question sitting underneath all of these
• "Subject to satisfactory evidence of building regulations approval."

Retentions are not declines

This one is worth its own heading because it catches so many people. A retention means the lender will lend, but will hold back part of the advance until the specified works are done and re-inspected.

So if the retention is £25,000 and you needed that £25,000 to do the works, you have a problem. It is one of the most common reasons a purchase collapses after an offer has already been issued, and it is also one of the easiest to solve, because a bridge is frequently the way through it.

Two other practical points. A valuation is one person's opinion on one day, and a different lender using a different valuer can produce a different answer, particularly on borderline construction and movement cases. And ask at the outset whether you will be shown the report, because it tells you precisely what has to be fixed.

Japanese knotweed

Knotweed has a reputation worse than its current reality, mostly because the rules changed and the reputation did not.

The 7 metre rule is gone

Until 2022, valuers worked to a framework where knotweed within 7 metres of a property was reported and anything beyond it was not. RICS replaced that with an assessment based on the actual impact of the infestation rather than how far away it is.

Where knotweed is found inside the boundary, it now falls into one of three categories:

There is a fourth, Category D — Report, for knotweed growing off-site, within three metres beyond the boundary. It gets reported, but lenders are not expected to impose a retention for it, on the sensible basis that you cannot control somebody else's land. Beyond three metres from the boundary it is not categorised or reported to lenders at all.

What a lender wants to see

On categories A and B, a treatment plan from a specialist contractor backed by an insurance-backed guarantee, typically running 5 to 10 years, transferable to future owners and to the lender. The guarantee is the part the lender actually cares about, because it is what protects the security if the treatment fails.

Where bridging fits

Treatment plans run over multiple growing seasons, which no mainstream purchase timetable can accommodate. So a bridge funds the purchase, the plan goes in, the guarantee is issued, and the property refinances onto a mortgage once the paperwork exists.

The knotweed is not gone at that point, and it does not need to be. The documented plan and the guarantee are what make the property lendable again.

The honest caveat. Lender policy varies more on knotweed than on almost anything else, and most lenders do not publish it. Across the 67 lenders in our criteria database (our wider panel runs to over 120 lenders across all product types) only a handful state a knotweed position at all, and at least one mainstream lender's criteria say simply that it is not accepted. It is a question to ask a specific lender about a specific property, not something to assume.

Spray foam insulation

Spray foam is the issue that has caused the most unnecessary panic and the most unnecessary expenditure.

The problem, as lenders see it. Sprayed foam applied to the underside of a pitched roof can trap moisture against the timbers, and it hides them, so a surveyor cannot inspect for decay. The lender's concern is not the foam itself. It is the unknown condition of the roof structure underneath it. Some lenders refused to lend at all on any property with it.

What changed. The Property Care Association and the Residential Property Surveyors Association set up a working group, with lenders, insurers, surveying institutions and the spray foam industry involved, and produced an inspection protocol for properties with sprayed foam on pitched roofs. It gives surveyors a defined process: what to record, what to assume, and what evidence is needed before reaching a conclusion. The point, in the Property Care Association's own words, is to let decisions be made on each roof's condition and risk factors rather than on the foam "just being there".

So is removal always necessary? No. Where an inspection finds the risk has not materially increased, a number of lenders will proceed. Where it finds decay, saturation, inadequate ventilation or a badly executed installation, removal is the answer.

What it costs. An inspection report is a few hundred pounds. Removal runs to several thousand and sometimes considerably more, because getting closed cell foam off rafters is slow work, and a bad removal damages the timbers it was meant to protect. Reinstating the insulation and making good adds to that.

The order to do things in. Get the inspection report first. Spending five figures on removal before establishing whether removal is even needed is a common and expensive mistake. There is also an active scam problem here, with cold callers telling homeowners the foam has to come out immediately, so use a contractor through a recognised trade body.

Where bridging fits. A bridge funds the purchase of a property with foam, the inspection or the removal happens, and the property refinances. The timescale is weeks, not months.

Cladding and external wall systems

Flats in buildings with cladding concerns are the hardest category on this page, for one reason. The problem is not yours to fix.

Everything else on this page is within the control of whoever owns the property. Cladding remediation sits with the building owner, the freeholder and the government schemes, and a leaseholder cannot force the pace.

The position has improved substantially from the worst period. Lenders are considerably more willing to lend where a building is in a recognised remediation scheme or where the right assessment exists, and leaseholder protections under building safety legislation have changed the liability picture. But a building without the necessary paperwork can still be effectively unmortgageable, and the only honest advice is to establish the building's status before committing to anything.

Bridging can work where there is a defined event that resolves it, such as an assessment being completed or remediation finishing on a known timetable. Bridging does not work where the answer is that the building will be dealt with at some point. That is not an exit.

The cheapest route back to lendable

People overspend badly here, usually by renovating to a standard the exit does not require.

The principle: you are not refurbishing to sell, you are refurbishing to pass a valuation. Those are different standards. A mortgage valuer is asking whether the property is habitable, safe, and saleable if repossessed. They are not assessing the quality of your tiling.

The minimum, in rough order of cost effectiveness:

• A functioning kitchen. Units, a worktop, a sink with hot and cold water, and space and services for a cooker. A basic trade kitchen professionally fitted costs a fraction of a specified one and passes exactly the same test
• One working bathroom. A bath or shower, a basin and a WC, properly plumbed and with hot water
• Working services. Water, electricity, and a heat source that works. Certification for the electrical installation and the gas appliances
• Weathertight and secure. A roof that does not leak, windows that close and lock, external doors that secure, no obvious water ingress
• Whatever the specific defect was. The damp proofing, the engineer's report, the knotweed guarantee, the lease extension
• An EPC. Required, and cheap

What you can usually leave alone: decoration, flooring beyond something serviceable, the garden, the kitchen specification, the bathroom suite, and anything cosmetic. Those affect the sale price. They rarely affect mortgageability.

The exception. If your exit is a sale rather than a refinance, this changes completely, because you are selling to a buyer rather than passing a valuer. Decide which exit you are aiming at before you decide the specification, because that decision sets the budget.

And build the contingency in. A refurbishment of a property with one known defect routinely finds a second one. Fifteen to twenty per cent on top of the quoted cost is prudent, and lenders prefer to see it there.

The six month rule, and planning around it

This catches more refurbishment projects than any other single policy, and it is not a property problem at all.

What it is. Many mainstream and buy to let lenders apply an ownership length requirement before they will remortgage a property. The common form is that within the first six months of ownership they will either not lend at all, or will lend only against the original purchase price rather than the new, higher value.

Why it matters. The whole buy, fix, refinance model depends on refinancing against the improved value. If the lender will only recognise what you paid, the uplift you have just created is invisible, and the money you spent on the works is trapped until month six.

It is not universal. A meaningful number of lenders have no such rule, and others will lend against the improved value inside six months where the uplift is evidenced by the works. This is one of the clearest examples of why which lender you use matters more than what rate they quote.

How to plan around it. Take a bridge term that comfortably exceeds six months from completion, not from when the works finish. A twelve month facility on a three month refurbishment is not over-borrowing, it is sensible sequencing, and where the rebate basis is good an early redemption costs you very little. Start the refinance application at around month four so the offer is ready when the clock runs out. And establish at the outset, before the bridge is drawn, which exit lenders will look at the case, rather than finding out about the rule in month five.

What you cannot make lendable

Some properties should be walked away from, or bought only with cash and no expectation of a mortgage exit.

Anything where the defect is outside your control and has no date. A cladding situation with no remediation timetable. An absent freeholder where the court process has not started. A neighbour's structural problem affecting your building. You cannot underwrite an exit you do not control.

Property below the minimum value threshold. If the finished property will be worth less than the minimum a lender will take as security, there is no refinance exit at any point. The only exit is a sale, and the project has to work on that basis alone.

An agricultural occupancy condition you have not already removed. Removal is a planning application with an uncertain outcome and a long timetable. Buying one on the assumption it can be lifted is speculation, not a plan.

Unmanageable flood risk. If insurance cannot be obtained, no mainstream lender will lend, now or later. That is a permanent condition.

Anywhere the location is the problem. Next to a use that depresses marketability, with no road access, over a contaminated site. You can fix a building. You cannot move it.

Active structural movement needing long-term monitoring. Twelve months of readings before anybody will commit is longer than most bridging terms, and the outcome is unknown at the start.

Anything where the numbers only work perfectly. If the project needs the top of the valuation range, no overrun and a fast refinance, your margin for error is zero. Properties with known defects produce overruns as a matter of routine.

We decline enquiries on these grounds regularly, and occasionally talk clients out of properties they are enthusiastic about. A bridge that cannot exit is worse than no bridge at all.

How the funding actually works

The standard structure is buy, fix, refinance, and it has three stages.

Day one. The bridge funds the purchase, typically up to 75% of the price on a gross basis, which nets down to around 60% to 65% after the arrangement fee and the retained interest. Many lenders will also fund the works, in some cases the full cost. Our rates page sets out every charge.

During the works. Works money comes out in stages behind the work rather than in front of it. You pay for a stage, the lender's surveyor inspects it, the lender reimburses you. That creates a working capital requirement separate from your deposit, and it is the most common reason a project runs out of money halfway through. There is more on this on our heavy refurbishment page.

The exit. Either a refinance onto a buy to let or residential mortgage against the improved value, or a sale. The refinance route is where the six month rule bites.

Terms typically run 12 to 24 months, there is usually no early repayment charge, and most lenders rebate unused retained interest, so taking a longer term than you expect to need is cheap insurance. If you or a close family member will live in the property, the loan is regulated, which narrows the panel considerably and has to be arranged on that basis from the start.

Our Step-by-Step Loan Process at Bridging Finance Broker

Related