Non-Standard Construction: How to Get a Mortgage in 2026
Non-standard construction refers to any property built using materials or methods that differ from the traditional UK standard of brick or stone walls with a tile or slate roof. Many of these homes look normal from the outside but have hidden structural differences inside.
Key Points
- Non-standard construction refers to properties built with materials other than traditional brick or stone walls and tile or slate roofs, including timber frames, steel frames, concrete panels, and modular builds.
- Securing mortgages and insurance for non-standard construction properties typically requires specialist lenders and insurers, often with higher deposits, interest rates, and premiums.
- A professional RICS building survey is essential before purchasing, as standard mortgage valuations cannot identify construction-specific defects or structural issues.
- While non-standard properties often have lower purchase prices, buyers should carefully consider financing complexity, insurance costs, and potential resale challenges before committing.
What Is Non-Standard Construction?
Common types include timber-framed houses, steel-framed buildings, precast concrete panels, and homes with flat or thatched roofs. For potential buyers, it's important to understand that not all lenders are willing to finance non-standard construction homes through traditional processes. Alternatives like bank statement mortgages from Griffin Funding can help self-employed borrowers qualify. Professional surveys or local council records can confirm a property's classification.
Types of Non-Standard Construction
Non-standard construction refers to any property built using materials or methods outside the conventional brick-and-stone walls with tile or slate roofs. Common types include:
- Timber frame – a wooden skeleton with outer cladding
- Steel frame – metal structures, often clad in brick or render
- Concrete panel and PRC – prefabricated reinforced concrete used heavily after World War II
- Modular builds – factory-made sections assembled on-site
- Thatched roofs – traditional organic roofing needing specialist care
- Flat roofs and shingle cladding – alternative roof and wall coverings
Some builds, like BISF steel-frame and certain PRC designs (Airey, Cornish Unit), carry extra risks and may be classed as legally defective.
How to Identify Non-Standard Construction
Identifying non-standard construction is a process that combines visual checks, document searches, and professional assessment. Many non-standard homes look ordinary from the outside, so surface inspection alone is not reliable.
Start by examining external walls. Render, pebble-dash finishes, or unusually thick or thin walls can signal concrete or timber frames hidden beneath. Next, check your property deeds and local council records for construction details, and ask estate agents for written disclosure.
For older properties, search for designations under the Housing Act 1985, which flagged certain post-war systems as defective. If the home has a steel or concrete frame, look for a PRC certificate proving that permanent structural repairs were completed.
When doubt remains, commission a surveyor experienced with post-war building systems. The Building Research Establishment lists over 500 distinct methods used between 1919 and 1976, so expert verification is often the only way to confirm what lies beneath the walls.
Defective vs Non-Standard Construction
Non-standard construction describes homes built with alternative materials, while defective construction is a legal designation for systems with proven structural faults.
The difference matters for buyers. Non-standard homes use timber, steel, or concrete frames instead of traditional brick and stone. Many are sound buildings that simply need specialist maintenance—moisture control for steel, rot prevention for timber.
Defective properties are different. The Housing Act 1985 identifies 28 specific systems, including Airey and Cornish Unit houses, as having inherent structural problems. These homes typically cannot secure a mortgage without a PRC Repair Certificate from a licensed engineer confirming remediation work.
Getting a Mortgage on Non-Standard Construction
A mortgage for non-standard construction is harder to secure than one for a typical brick-and-tile home. Lenders view these properties as higher risk because materials like steel frames can corrode or timber may rot over time.
You can still get financing, but expect stricter terms. Most mainstream lenders limit how much they'll lend, often capping loan-to-value at 75–80 percent. This means a larger deposit. Interest rates tend to run higher, and insurance premiums increase due to fire or structural concerns.
Specialist brokers help match unusual builds with willing lenders.
Insuring Non-Standard Construction Properties
Non-standard construction properties are homes built with materials other than traditional brick, stone, tile, or slate. These buildings—including timber-framed, steel-framed, or concrete panel homes—often need specialist insurers because standard policies exclude them.
Premiums run higher due to repair costs for issues like timber rot or steel corrosion. Always disclose your exact construction type; hiding it can void your cover. For post-war concrete homes, a PRC certificate is usually required before insurers will offer quotes.
Converting Non-Standard Construction to Standard
Converting a non-standard property to standard classification depends on which part causes the non-standard label. Roof materials can often be swapped—replacing shingles with slate or tile may achieve reclassification. However, properties built with steel or timber frames usually stay non-standard because the structural skeleton is permanent and cannot be removed.
For defective pre-cast reinforced concrete (PRC) homes, certified repair schemes offer a path forward. A PRC certificate proves approved remediation work was completed, making the property mortgageable and insurable without full reclassification.
Why Building Surveys Are Essential
A building survey is a detailed inspection that checks a property's condition and construction type. For non-standard homes, this survey protects you from hidden problems that basic mortgage valuations simply cannot detect.
Mortgage valuations serve lenders, not buyers. They assess risk quickly without examining materials or structure. Non-standard properties—especially those built between 1918 and 1975—need a RICS Level 3 Building Survey instead. This deeper inspection identifies construction-specific defects like steel-frame corrosion, concrete spalling, or rot caused by non-breathable modern coatings on older materials. The report also helps you secure specialist insurance and meet strict lending requirements.
Selling a Non-Standard Construction Property
Selling a non-standard construction property means finding buyers who can secure finance for unconventional builds. This restricts your market because most high-street lenders refuse mortgages on homes built with timber frames (especially pre-1970s), steel frames, concrete prefabs, or non-traditional roofing like felt or corrugated metal.
Your likely buyers are cash purchasers, specialist investors, or those using niche lenders. Sale prices typically fall below comparable standard homes.
Commission a structural engineer's report before listing. For concrete prefabs, obtain a PRC certificate. This transparency addresses buyer concerns about insurability and resale prospects.
Should You Buy a Non-Standard Construction Property?
A non-standard construction property can be a good buy if you plan carefully and accept certain trade-offs. Lower purchase prices often attract first-time buyers, but financing and insurance are harder to arrange, and selling later may take longer.
Before committing, confirm the exact construction type—brick cladding sometimes hides timber or steel frames underneath. Check whether the home appears on statutory defective lists and research material-specific problems like concrete spalling, steel corrosion, or timber rot.
Commission a RICS Level 3 survey and obtain a PRC certificate if required. These documents help unlock specialist mortgage and insurance options.
Frequently Asked Questions
What are the pros and cons of non-standard construction properties?
Non-standard construction properties are typically cheaper to purchase than equivalent standard construction homes, making them more affordable for some buyers. However, you will face limited mortgage options with potentially lower loan-to-value ratios, higher insurance premiums, and may encounter difficulties when selling the property.
Is a steel frame house considered non-standard construction?
Yes, steel framed houses are classified as non-standard construction because their structure relies on a metal frame rather than traditional brick, stone, or concrete walls. This classification affects both mortgage availability and insurance requirements for the property.
Do non-standard construction properties hold their value?
Non-standard construction properties may not hold their value as well as standard builds due to limited buyer pools, restricted mortgage options, and higher ongoing costs. Market demand tends to be lower, which can impact resale prices and the time it takes to sell.
How common are non-standard construction homes in the UK?
Non-standard construction homes became particularly common after World War II when they were built to address severe housing shortages using alternative materials and methods. Many of these properties still exist today, alongside newer non-standard builds that use modern construction techniques.
