Table of Content
Warning: Your home may be repossessed if you do not keep up repayments on your mortgage.
Mortgages for Non-Standard Construction Properties
Timber frame, steel frame, concrete and PRC, single-skin brick, thatch and prefab — if a high-street bank has said no, the right lender often says yes. We’ve placed non-standard construction mortgages for over a decade.
Free, no-obligation broker call · We’ll confirm if a property is mortgageable before you offer
Specialist mortgages for unusual builds
A non-standard construction property is any home not built the “standard” way — brick or stone cavity walls with a tiled or slated roof. Use a different material or method and lenders assess the property more carefully, but a mortgage is rarely off the table. There’s no separate “non-standard mortgage” product and no penalty rate by default; you apply for a normal residential or buy-to-let mortgage, and the job is simply matching the construction type and condition to a lender with appetite for it.
And it’s not a case of heading straight to a “specialist” lender. There isn’t really a separate breed of lender that exists just for non-standard construction — mainstream high-street lenders place a great many of these. Every lender draws its lines in a different place, so the skill is finding whose criteria fit your property. We go to the high street first wherever it fits and only widen the search when a property genuinely needs it — which keeps your deposit lower and your rate sharper.
Industry / BRE estimates — non-standard is more common than most buyers think
Standard 5–10% works on the more common types; only the trickiest cases need more
Why a PRC certificate & approved repair scheme matter for concrete homes
Whole-of-market — high-street lenders place far more of these than most people think
Non-standard construction mortgages — six things that matter
The fundamentals that decide whether a property is mortgageable, with whom, and on what terms.
The exact construction type
Timber frame, steel frame, concrete/PRC, single-skin brick, thatch, prefab. This is the single biggest factor — it sets the lender pool before anything else is considered.
Property condition & survey
Lenders want a survey by someone experienced in the construction type. Defects, damp or poor maintenance can narrow options; a clean report widens them.
Deposit & loan-to-value
The lower your LTV, the more lenders will look — but many accepted types take ordinary deposits. Lower-risk types reach 90–95%; only the trickiest cases need a larger deposit.
Certificates & repairs
For concrete/PRC homes, an approved repair scheme and PRC certificate transform mortgageability. For steel frame, a structural engineer’s report often helps.
Insurability
If a property is hard to insure (thatch, for example), it’s harder to mortgage. Lenders want to know specialist buildings cover is available and affordable.
Marketability & resale
Lenders assess how easily they could resell if they had to. A type with a reasonable pool of willing lenders is easier to mortgage now — and to sell later.
Mortgages by construction type
Each construction type carries a different level of lender caution and a different shortlist. Tap any type to see how lenders treat it — and where we have a dedicated guide.
Modern timber frame is widely used in UK new-build and is accepted by many high-street lenders on standard terms and standard deposits. Older timber frame, or homes where the timber is externally clad or exposed rather than protected by an outer brick skin, can need more careful routing and sometimes a structural survey.
- High-street appetite: Good for modern, well-maintained timber frame
- Deposit: Often standard (5–10%) for modern builds; more for older or unusual designs
- Watch-outs: External cladding type, condition of the frame, any movement or rot
- Our guide: Mortgage lenders for timber-frame houses
Single-skin (solid-brick) construction has one layer of brick rather than two with a cavity. Lenders associate it with damp, insulation and durability concerns, so the pool is narrower than for cavity walls — but a number of high-street lenders will consider it with a satisfactory survey, often on fairly normal terms.
- High-street appetite: Limited but real — routing is the lift, not a specialist lender
- Deposit: Often standard; some lenders prefer a little more
- Watch-outs: Damp, condition of brickwork, extent of single-skin (whole property vs an extension)
- Our guide: Which lenders accept single-skin brick construction
Prefabricated reinforced concrete (PRC) homes — Airey, Cornish Unit, Woolaway, Unity, Wates, Reema and others — were widely built post-war, and many types were designated defective under 1980s housing legislation. Most lenders will only lend on a PRC home that has been fully repaired under an approved scheme, evidenced by a PRC certificate from a structural engineer.
- Repaired & certified: Far more mortgageable — a good range of lenders will consider it, often on normal terms
- Unrepaired: Very difficult — usually a large deposit or cash purchase
- Deposit: Repaired homes can often be placed on more normal deposits; unrepaired needs far more
- Key document: PRC certificate confirming an approved repair scheme has been completed
Steel-frame houses, including many post-war and ex-local-authority BISF properties, sit in the middle of the risk scale. Lenders are cautious about corrosion and the long-term integrity of the frame, so a structural engineer’s report and evidence of condition (or reinforcement) can make the difference.
- High-street appetite: Selective — but lenders with the right criteria will consider it without going specialist
- Deposit: Often standard; some lenders prefer a little more on older frames
- Watch-outs: Corrosion, condition of the frame, any past reinforcement works
- Improving it: Reinforcement by a qualified structural engineer can widen the lender pool
Thatched homes are generally mortgageable, but the lender pool is more selective and insurance is central. Lenders want to see that adequate specialist thatch buildings insurance is in place — premiums are higher because of fire risk — and many thatched properties are also listed, which adds further criteria.
- High-street appetite: Selective; a number of lenders and specialists will lend
- Key requirement: Specialist thatch insurance arranged and affordable
- Often combined with: Listed-building status — see cob / clay lump / listed below
Ex-local-authority and high-rise flats can be non-standard for several reasons at once — construction method, building height, the proportion of privately owned flats in the block, and (post-Grenfell) external cladding. Each affects which lenders will consider the property.
- Height: Some lenders cap the number of storeys; others are comfortable with high-rise
- Cladding: An EWS1 form may be required for blocks above certain heights
- Ex-LA blocks: Lenders may want a minimum percentage of private ownership in the block
- Deposit: Often higher; varies widely by lender and block
Traditional methods like cob (clay, sand and straw, common in the South West) and clay lump (a Norfolk speciality) sit alongside listed period cottages as the “heritage” end of non-standard. These are lendable with the right lender, but condition, maintenance and listed-building obligations are scrutinised closely.
- Lender appetite: Selective — lenders comfortable with period & listed property
- Watch-outs: Condition, breathability/maintenance, listed-building consent for alterations
- Deposit: Varies with condition — not always as high as you might expect
“Prefab” spans everything from post-war temporary housing to today’s factory-built modular and modern methods of construction (MMC). Modern, warranty-backed MMC homes (with an accepted new-home warranty such as those recognised by lenders) are increasingly mainstream; older prefabs are assessed much more cautiously.
- Modern MMC: Growing lender acceptance where a recognised warranty is in place
- Older prefabs: Specialist routing, larger deposit, careful survey
- Key requirement: An acceptable warranty / certification for the system used
How lenders assess a non-standard property
The detail behind every non-standard decision — what lenders look at, why it matters, and what evidence strengthens your case.
Before anything else, a lender wants to know exactly what the property is built from and how. The surveyor identifies the construction type, and that determines whether the property even reaches a lender’s “acceptable” list. Two homes at the same price can have completely different lender pools purely because of how they’re built.
- Identified by: The lender’s valuer / surveyor, sometimes with a more detailed specialist survey
- Why it matters: It sets the shortlist of lenders before deposit, income or anything else is considered
- Strengthen it: Any existing surveys, build records or warranties that confirm the construction method
A surveyor experienced in the relevant construction type assesses condition and flags defects or maintenance needs. For non-standard homes the survey carries more weight than usual — a clean report can open up lenders, while flagged issues can close them. Some lenders make a maintenance plan a condition of the mortgage.
- Use the right surveyor: One with experience of your specific construction type
- Budget for it: Ongoing maintenance can affect both value and future mortgageability
- Strengthen it: Provide previous surveys, reports and any remedial work guarantees
For concrete and PRC homes, whether the property has been repaired under an approved scheme is usually the make-or-break factor. A completed repair, certified by a structural engineer with a PRC certificate, moves a property from “very hard to mortgage” to “lendable with the right lender.”
- Repaired + PRC certificate: Opens up a meaningful pool of lenders
- Unrepaired / no certificate: A much larger deposit or cash purchase
- Strengthen it: Full documentation of the repair scheme and engineer’s sign-off
Lenders need the property insured as their security. Where buildings insurance is hard or expensive to get — thatch being the classic example because of fire risk — it can affect both the mortgage decision and your monthly costs. Specialist insurers experienced in the property type usually offer far better terms than mainstream providers.
- Arrange early: Confirm specialist cover is available before you commit
- Shop around: Premiums vary widely between mainstream and specialist insurers
- Reassures the lender: Cover in place strengthens the application
A lender assesses how easily it could resell the property if it ever had to repossess. The smaller the pool of buyers (and their lenders) for a given construction type, the more cautious the lender — usually expressed as a lower maximum LTV and a larger deposit requirement. Choosing a type with a reasonable lender pool helps you now and when you come to sell.
- Effect: Lower LTV caps and larger deposits on higher-risk types
- Future-proofing: A type many lenders accept is easier to sell on
- Mitigate it: Keep the property well-maintained and documented
The LTV you need is often the single most controllable factor. A bigger deposit reduces the lender’s risk and widens the pool — but you rarely need a huge one. Lower-risk types reach 90–95% LTV, and many other types are placeable on fairly normal deposits with the right lender; only the trickiest cases call for a larger one.
- Lower-risk types: Modern timber frame, accepted MMC — up to 90–95% at the right lender
- Trickier types: Older steel frame, single-skin brick, repaired PRC — often still ordinary deposits; a larger one only where the lender’s criteria call for it
- Rate impact: A lower LTV usually means a better rate as well as more lenders
Some properties can be modified to reduce structural risk and move closer to standard-construction status — reinforcing a steel frame, or completing a PRC repair scheme. The work can be complex and costly and isn’t always necessary, so a qualified structural engineer should assess it and provide a cost estimate first. A completed, certified repair often transforms what a property can be mortgaged for.
- Get advice first: A structural engineer confirms whether work is needed and what it costs
- Document everything: Certificates and guarantees are what lenders rely on
- Payoff: A wider lender pool, a higher LTV and a better rate
A small number of lenders will look at a property’s construction type and give a view on appetite before they instruct a valuer — a pre-valuation (or “pre-application”) query. It’s not a guarantee of an offer, and most lenders won’t do it, but where it’s available it’s invaluable on non-standard cases: we can sound out whether a lender is likely to lend before you commit to a full application and a hard credit check.
- Only a small pool offer it — and it’s an indication of appetite, not a firm commitment
- Saves wasted applications and avoids unnecessary declines landing on your credit file
- Most useful on unusual or borderline construction types, where a straight application is a gamble
- We use it wherever a lender allows it to de-risk the case before you apply
Send us the construction type — we’ll tell you if it’s mortgageable
The property type, condition, your deposit and the survey if you have one. We’ll confirm which lenders have appetite, on what deposit and at what sort of rate — before you commit to an application.
Non-standard construction — lender appetite by type
A general guide to how the market treats each construction type. Use it as a reference — appetite varies by lender, property and condition, and we’ll model the exact shortlist for your case.
| Construction type | High-street appetite | Lender pool | Key requirement |
|---|---|---|---|
| Modern timber frame | Good | Wide | Good condition & survey |
| Older / clad timber frame | Good | Good | Structural survey |
| Single-skin / solid brick | Selective | Selective | Satisfactory survey, damp check |
| Steel frame (incl. BISF) | Selective | Selective | Engineer’s report |
| Concrete / PRC — repaired | Selective | Selective | PRC certificate |
| Concrete / PRC — unrepaired | Very limited | Very narrow / cash | Approved repair scheme |
| Thatched roof | Selective | Selective | Specialist thatch insurance |
| High-rise / ex-LA flats | Selective | Selective | EWS1 / % private ownership |
| Cob / clay lump / listed | Selective | Selective | Condition & listed consents |
| Modern MMC (warranty-backed) | Growing | Widening | Recognised new-home warranty |
Recent non-standard cases we’ve placed
Three recent placements across different construction types. Tap any card for the full detail.
Aaron & Megan, Leeds — timber-frame house declined by their own bank, placed on high-street terms
The situation: Aaron and Megan, first-time buyers with a combined income of £58,000 and a £26,500 deposit (10%), were buying a 1980s timber-frame semi in Leeds at £265,000. Their own bank approved them in principle, then declined at the valuation stage the moment the surveyor wrote “timber frame” on the report — leaving them three weeks from exchange and convinced they’d lose the house.
What we did: We recognised the build for what it was — a standard, well-maintained modern timber frame, the kind used across UK new-build — and knew several mainstream lenders treat it as an ordinary house. We routed it to Halifax, submitted the valuation confirming the frame was sound, and presented it as the normal residential case it was. No specialist lender, no inflated deposit, no premium rate.
The outcome: Approved at 90% LTV on a standard 5-year fixed high-street rate — the same deal any brick-and-mortar buyer would have got. The offer was issued in nine days and completion held to the original deadline.
“Our bank let us get all the way to valuation and then said no because of the timber frame. We thought the house was gone. Jamie knew it was a normal timber-frame build and exactly which lender would just treat it as a normal mortgage — sorted in days, same rate as everyone else.”
Dawn, Plymouth — repaired Cornish Unit (PRC) home mortgaged after two other brokers said no
The situation: Dawn was buying an ex-local-authority Cornish Unit (PRC) house in Plymouth at £180,000 with a 25% deposit. The property had been repaired under an approved PRC scheme years earlier, but two previous brokers had told her it “couldn’t be mortgaged” and she was within days of pulling out of the purchase.
What we did: We tracked down the original PRC certificate confirming the approved repair, along with the structural engineer’s sign-off, and routed the case to a lender that lends on certified, repaired PRC construction. Packaging the certificate and engineer’s documentation up front meant the valuation went through without a single query.
The outcome: Approved at 75% LTV on a competitive rate. The certificate was the entire key — with it, a case two other brokers had called “unmortgageable” became a clean, straightforward approval.
“Two brokers told me flat out it couldn’t be done and I’d almost given up on the house. Kiran asked for the repair certificate, found the right lender and it went through without a hitch. I can’t thank her enough.”
The Hardys, Norfolk — single-skin brick cottage placed where the high street wouldn’t even look
The situation: The Hardys were moving from a modern semi to a period cottage with single-skin (solid-brick) walls in Norfolk at £310,000, porting £140,000 of equity. Their existing lender refused to consider the construction at all, and a second lender wanted an unworkable 35% deposit — effectively pricing them out of the move.
What we did: We matched them to a lender that accepts single-skin brick with a satisfactory survey, and arranged a survey by a surveyor experienced in solid-wall period homes — so the damp and durability questions were answered with evidence up front rather than left to an underwriter’s assumption.
The outcome: Approved at 80% LTV with no inflated deposit required. The clean specialist survey plus the right lender choice turned a flat “no” into a straightforward completion six weeks later.
“Our own bank wouldn’t touch it and another wanted a deposit we simply didn’t have. Greg knew exactly who lends on solid-brick cottages and got the right survey done — we completed six weeks later on the home we actually wanted.”
Illustrative cases based on the type of work we do. Individual circumstances and lender criteria vary.
Non-standard construction mortgage specialists
Unusual builds are one of the property types we work with most — we arranged over 200 non-standard construction mortgages in 2025 alone. We sit down with buyers of timber-frame, concrete, steel-frame, single-skin and thatched homes every week, and we’ve seen how often a high-street “no” is really just the wrong lender. Tell us the construction type and we’ll find the lender with appetite for it.
Send us the construction type, condition and your deposit. We’ll come back with the lenders that will consider it, the likely deposit and the sort of rate to expect — before you spend money on an application.
Timber, steel, concrete/PRC, single-skin brick, thatch, cob, prefab and MMC — we know the lender appetite for each.
There’s no separate breed of “non-standard” lender — many high-street lenders place these. We match the property to the lender whose criteria fit best, which keeps your deposit lower and your rate sharper.
PRC certificates, structural engineer’s reports, listed-building and cladding considerations — we package the application so it lands first time.
We confirm whether a specific property can be financed before you commit — so you don’t risk a decline on your credit file.
Non-standard homes are often more affordable — we help first-time buyers and movers get them financed sensibly.
315 Google reviews — built on placing the cases other brokers and high-street lenders have turned away.
Meet Jamie
Non-standard construction mortgages — FAQ
The questions buyers of non-standard homes ask us most.
Yes. Plenty of high-street lenders will lend on non-standard homes — there’s no separate “non-standard mortgage” product and no automatic penalty rate. You apply for an ordinary residential or buy-to-let mortgage; the lender simply assesses the property as security more carefully.
The decisive factor is matching the exact construction type and the property’s condition to a lender whose criteria fit. Timber frame and many modern methods of construction are widely accepted; concrete/PRC, steel frame and single-skin brick just need more careful lender selection.
Any home not built with brick or stone cavity walls and a tiled or slated roof. That includes timber frame, steel frame (such as BISF), concrete and PRC homes (Airey, Cornish Unit, Reema, Wates and others), single-skin or solid brick, thatched roofs, cob and clay lump, high-rise and ex-local-authority flats, prefabs, and modern methods of construction (MMC).
Each type carries a different level of lender caution — some are barely different from standard in lenders’ eyes, others need more careful lender selection.
Usually not. There isn’t really a separate breed of lender that exists only to lend on non-standard construction — many mainstream, high-street lenders place these cases routinely. Every lender just draws its lines in a different place, so the job is finding the one whose criteria fit your particular property.
We go to the high street first wherever it fits, and only widen the search when a property genuinely needs it. That keeps your deposit lower and your rate sharper than assuming a “specialist” route is required.
Often less than you’d expect. Common types like modern timber frame can be mortgaged on an ordinary 5–10% deposit at the right lender, and many other types are placeable on fairly normal deposits too.
Only the trickiest cases — unrepaired concrete/PRC, or properties in poor condition — call for a notably larger deposit. As a rule of thumb, the harder a property is to resell, the more deposit a lender tends to want.
Not necessarily. Where the property meets a mainstream lender’s criteria you get the same rates as any standard home — which happens more often than people assume, because so many of these cases are placeable on the high street.
A higher rate tends to come in only for the genuinely difficult cases (poor condition, unrepaired PRC), and even then it can be a stepping stone, with the option to remortgage onto better terms later if the property is improved.
Often yes, but PRC (prefabricated reinforced concrete) homes need extra care. Many types — Airey, Cornish Unit, Woolaway, Unity and others — were designated defective under 1980s housing legislation. Most lenders will only lend on a PRC home fully repaired under an approved scheme, evidenced by a PRC certificate from a structural engineer.
An unrepaired PRC property is very difficult to mortgage and usually needs a large deposit or a cash purchase. A repaired and certified PRC home is far more mortgageable — often on fairly normal terms.
Yes — timber frame is one of the more mortgageable non-standard types. Modern timber-frame homes built to current standards are accepted by many high-street lenders on standard terms, and timber frame is widely used in new-build construction.
Older or externally-clad timber-frame properties, or those with exposed timber rather than a protective outer skin, can need more careful lender selection and sometimes a structural survey — but options are good with the right routing. See our timber-frame mortgage guide.
Yes, though the lender pool is narrower than for cavity-wall homes. Single-skin (solid-brick) construction has one layer of brick rather than two with a cavity, which lenders associate with damp, insulation and durability concerns.
A number of high-street lenders will still consider single-skin brick with a satisfactory survey, often on fairly normal terms. See our guide to which lenders accept single-skin brick construction.
Because lender appetite for non-standard construction changes constantly and varies sharply by type. A whole-of-market broker knows which lenders currently lend on your construction type, what conditions they’ll attach, and how to present the application so it lands first time.
Applying to the wrong lender risks a decline on your credit file; the right routing is often the difference between an ordinary high-street rate and a needlessly expensive one — or between an approval and a refusal.
Outstanding service and clear communication are at the core of what we do. But don’t just take our word for it—read firsthand experiences from our clients and discover why they rate us a 5-star mortgage broker.
