A non-standard construction house is one whose walls aren’t built in the conventional way, which in the UK usually means brick or block cavity walls or solid brick or stone under a tiled or slated roof. Many non-standard houses are perfectly sound and mortgageable. A smaller group, mainly certain PRC (precast reinforced concrete) houses, carry a known structural defect and are hard to mortgage unless they’ve been repaired under a recognised scheme. The key is knowing which type you’re looking at before you commit.
What does “non-standard construction” mean?
It’s a lender’s and insurer’s term rather than a legal one. Broadly, it covers houses built using systems other than traditional masonry, most of them put up in large numbers after the First and Second World Wars when bricks and bricklayers were in short supply. Councils commissioned hundreds of thousands of homes from factory-made or rapidly built systems. Many were later sold to tenants under Right to Buy and now come onto the open market.
Lenders treat these houses differently because each system has its own way of ageing and failing, and some have well-documented defects. Each lender sets its own criteria. One may lend on a particular type with a satisfactory valuation, another may decline it outright, and a third may ask for a specialist report first.
Common types of non-standard construction
The Building Research Establishment (BRE) catalogued dozens of systems in its non-traditional housing reports. The main families you’ll come across are:
- PRC (precast reinforced concrete). Factory-made concrete columns and panels bolted together on site. Names include Airey, Cornish Unit, Unity, Reema, Orlit, Woolaway, Boot, Wates and many more. Often semi-detached, frequently with a concrete-panelled or pebbledashed ground floor and sometimes a different upper-floor finish.
- In-situ (cast in place) concrete. Walls poured into shuttering on site. The best known is Wimpey no-fines; Laing Easiform is another. We cover these in a separate guide to Wimpey no-fines houses.
- Steel-framed. A steel frame clad in other materials. The BISF (British Iron and Steel Federation) house, with steel sheeting on the upper storey, is the most recognisable; there are other steel systems too.
- Timber-framed. Modern timber frame is widely built and many lenders treat it as standard. Older or unusual timber systems, and some timber-clad houses, may still be classed as non-standard.
- Large panel systems and other system builds, including some flats and maisonettes, plus prefabs and modern methods of construction.
What is a designated defective PRC house?
In the early 1980s, serious problems were found in certain PRC houses, starting with the Airey house. Carbonation of the concrete and, in some cases, high chloride levels allowed the steel reinforcement to corrode. Corroding steel expands, cracking the concrete around it, typically in the columns and at the ring beam.
Parliament responded with the Housing Defects Act 1984, later consolidated into Part XVI of the Housing Act 1985. Under it, specific house types were designated as defective by reason of their design or construction. The designated types include Airey, Boot, Cornish Unit, Orlit, Parkinson, Reema Hollow Panel, Unity, Wates, Woolaway and a number of other PRC systems.
The legislation also gave eligible owners, within time limits set for each designation, a right to assistance from the local housing authority: a grant towards reinstatement, or repurchase of the house.
For a buyer today, the practical point is this: an unrepaired designated PRC house is generally very difficult to mortgage, which limits who can buy it and affects its value.
PRC repair schemes and certificates
Designated houses can be made mortgageable again by a structural repair to an approved specification. That usually means replacing the PRC walls with traditional masonry, at least on the ground floor, or otherwise rebuilding the load-bearing structure.
From 1985 to 1996, a subsidiary of the NHBC called PRC Homes Ltd licensed approved repair schemes for designated house types and kept a register of repaired homes. BRE Global now runs a PRC repair scheme that builds on that system: registered practitioners issue a Certificate of Structural Repair, which is only valid once it’s entered on the scheme’s register of properties.
If you’re buying a repaired PRC house, your conveyancer should get:
- the repair certificate, and confirmation that it covers this address and is registered where the scheme requires it;
- details of which repair scheme was used and who signed off the work;
- any later alterations that might affect the repair.
A repaired and properly certified PRC house is usually treated by lenders much more like a conventional house. Lenders’ requirements still vary, so check with your lender or broker. We don’t issue PRC certificates; that’s a matter for the scheme’s registered practitioners.
How to tell if a house is non-standard construction
Clues to look for on a viewing:
- Concrete panels or posts visible at ground level, or render and pebbledash with a “panelled” look.
- Steel sheeting on the upper floor (typical of BISF).
- A 1940s to 1970s council-built estate where many houses look identical and different from the brick houses nearby.
- Unusually thin walls, or no visible brick bond at all.
- Inside the loft, concrete or steel framing, or exposed rough concrete at the gable wall.
- The listing particulars or EPC describing the walls as “system built” or “timber frame”. You can look up a home’s energy certificate on GOV.UK.
Be careful with houses that have been refaced in brick. Some PRC houses have had a new outer brick skin, which can be part of an approved repair, or can simply hide the original structure without dealing with it.
Can you get a mortgage on a non-standard house?
Often, yes, but it depends on the type and the lender:
| Type | Typical lender view |
|---|---|
| Modern timber frame | Usually treated as standard |
| Wimpey no-fines and similar in-situ concrete | Often acceptable to many lenders, subject to valuation |
| Steel-framed (e.g. BISF) | Varies; some lenders accept, some ask for a specialist report |
| Designated PRC, repaired and certified | Often acceptable |
| Designated PRC, unrepaired | Generally very difficult; cash buyers or specialist lending |
These are broad patterns, not rules. Speak to your lender or a broker before you spend money on searches and surveys, and remember that whoever buys from you later will face the same question. Buildings insurance can also cost more or be harder to arrange for some types.
The lender’s mortgage valuation will flag the construction, but it isn’t a survey of the structure.
What a surveyor checks on a non-standard house
On a non-standard house, we focus on:
- Identifying the system as far as practical, and whether it is a designated type;
- External walls and frame for cracking, rust staining, spalling concrete and distortion, particularly at columns, ring beams and the base of the walls;
- Evidence of repair or recladding, and whether it looks consistent with an approved scheme, so your conveyancer knows what paperwork to chase;
- Later alterations such as extensions, external wall insulation or removed walls that may affect the structure;
- Damp, condensation and thermal performance, which are common weaknesses of early concrete and steel houses;
- Roof, floors and services, as on any house.
A survey is a visual, non-invasive inspection. It can’t confirm the internal condition of concealed steel or reinforcement, and we’re not structural engineers. Where something needs opening up or testing, we’ll say so plainly and tell you what kind of specialist to instruct.
Which survey do you need?
For most non-standard houses we recommend a Home Survey Level 3 (from £570, fixed fee quoted for the property). It gives a fuller account of the construction and its condition and more detailed advice on repairs. Our guide to which survey level you need explains the differences, and our list of questions to ask before you offer is a good place to start with the seller.
We cover a 90-minute radius of Huddersfield, including much of Yorkshire, Greater Manchester and Derbyshire, where post-war council estates with non-standard houses are common. Get in touch with the address and we’ll tell you what we’d expect to look at.
Sources and further reading
- Housing Act 1985, Part XVI: Assistance for owners of defective housing — legislation.gov.uk
- Housing Defects Act 1984 — legislation.gov.uk
- Pre-cast reinforced concrete repair scheme — BRE
- Non-traditional housing: a collection of BRE publications (AP 149) — BRE
- The British Iron & Steel Federation steel framed house — BRE