Non-standard construction: what to know

When it comes to construction, not all houses are created equal. If your property is deemed as non-standard construction, you have more to think about than if you had a standard home. But how can you tell them apart?

Non-standard construction properties aren’t built with stone or brick and don’t have a slate or tile roof. They’re considered non-standard because they can be more expensive and more complicated to maintain; they also tend to have a higher risk of deterioration. 

Most traditional mainstream insurance companies are more hesitant to insure non-standard properties because they lack the expertise to assess the risk properly. Those who do will likely overcharge for the premium, while some will simply refuse to provide a quote altogether.

There’s quite a bit to remember when insuring a non-standard home. Let’s take a look at what that means, along with ways of determining whether your property is standard or not.

What is non-standard construction?

What does non-standard construction mean? Well, properties are considered non-standard when not made with standard materials: brick or stone for the foundation, tile or slate for the roof. 

If any part of the property uses other construction materials, it’ll be considered a non-standard home.

Let’s take a look at a few examples:

• Example 1: Property A has stone walls but uses shingles for its roof. This is a non-standard construction because the roof uses non-standard materials.

• Example 2: Property B has a brick outer wall and a tiled roof but with a timber frame. This is still considered a non-standard construction home because timber isn’t a standard material.

Just because a property looks standard from the outside doesn’t mean it actually is. If you want to confirm what property type you have, it’s best to commission a surveyor knowledgeable about non-standard construction methods. You may also consult your local council’s building control to see if they have any records regarding your property.

Which types of construction are considered non-standard?

There are hundreds of non-standard homes that currently exist in the UK. In fact, just for houses built between 1919 and 1976, the Building Research Establishment has identified over 500 different construction types!

Here are some of the most common property types you’ll find:

• Steel-framed construction: Steel frames are prone to corrosion, which can cause other hidden structural issues. The most common steel-framed house is the BISF house, built by the British Iron and Steel Foundation.

• Timber-framed construction: These houses typically have a timber frame and use other materials, such as stone or brick, for the outer wall. Despite the potential for these houses to be energy efficient, timber poses a higher fire risk and is more susceptible to damp.

• Prefabricated/Precast concrete construction: Prefab concrete houses were meant to temporarily solve the housing shortage after World War II, especially for those who lost their homes during the Blitz. Because they weren’t built to last, repairing them can be costly. The most common ones you’ll find are Cornish units and Airey houses.

• Cob construction: Cob houses, made from a combination of subsoil, straw, and clay, can last for centuries. Despite its durability, maintaining a cob house requires specialist techniques, which are usually expensive.

The distinction between defective vs non-standard construction

Because there are so many non-standard construction homes built all over the UK, the Building Research Establishment surveyed each one in the 1980s. As it turns out, some types of homes suffer from severe structural defects.

These “defective” houses, as designated by the 1984 Housing Defects Legislation, require significant changes to be considered safe. Owners of these houses will need to obtain a PRC certificate proving that crucial structural changes were made with the approval of a PRC-licenced structural engineer.

The House of Commons Library has a research briefing that lists the types of homes deemed “defective” by the Secretary of State as part of the 1985 Housing Act. Some of these defective property types include:

• Airey
• Cornish Unit
• Myton
• Tarran
• Wessex

How to tell if a house is non-standard construction

Sometimes, you can tell right away if a house has non-standard construction. For example, if you see a newly built house with glass walls or an older property with a thatched roof, you know they’re non-standard.

But what about the not-so-obvious ones?

Here are a few things you can try to determine if your house was built with non-standard construction methods:

• Check the paperwork: Read through the documents that came with the house and see if any of them mention the original construction. 

• Ask the local council: Your local council’s building control department may still hold records about the construction of your house.

• Enquire with the neighbours: If your house is semi-detached, try asking your neighbours if they know about its construction. You can also ask other residents along your street, especially if the surrounding houses look similar.

• Commission a building survey: If you’ve asked everyone and still can’t find anything about your house’s construction, it’s time to commission a building survey. Make sure your surveyor is familiar with the types of non-standard houses in your area.

Can you convert a non-standard construction to a standard one?

In other words, can you change a non-standard construction?

Yes. Converting a non-standard building to standard construction is possible, depending on what part of the house is deemed non-standard. Consider these two scenarios:

• Scenario 1: Property A was originally built with stone walls and shingles for its roofing. Its new owner decided to change to a slate roof, so the house is now considered a standard building.

• Scenario 2: Property B is a steel-framed house. A conversion to standard construction is impossible because the foundation’s material can’t be changed (steel).

Houses with defective construction can’t be converted to standard homes due to how they were built initially. The only way to proceed with such a property, especially if you’re trying to insure it, is to obtain a PRC certificate (if you haven’t yet). This certificate proves that a PRC-licenced structural engineer approved the required repairs.

Can you insure a property with non-standard construction?

You can still insure a non-standard construction house but with higher insurance costs. Insurers will consider that maintaining and repairing non-standard construction houses will always be more expensive than those of their standard counterparts.

Keep in mind that if your house’s construction type was originally classed as defective, a PRC certificate would be the key to obtaining buildings insurance for your home.

If you want an insurance company willing to insure non-standard buildings, we can help. Call us to discuss your property’s construction type and produce a quote based on your needs.

Recap: The difference between standard vs non-standard construction

In a nutshell, the main difference between standard and non-standard construction houses is the building materials used. Standard houses must only be made from brick or stone for the foundation and slate or tile for the roof. Anything different is considered non-standard construction.

Converting a non-standard construction house to standard construction is not always possible because it depends on the material and its use. A conversion is possible if the non-standard material can be easily replaced without affecting the house’s structural integrity. If not, then the house remains non-standard.

Keep in mind that the 1985 Housing Act considered some non-standard houses defective. That’s because they present serious structural problems and require extensive changes to improve their safety. Insuring houses deemed defective requires a PRC certification, proving that structural changes were performed under the direction of a structural engineer.

How Howden can help

Through our strong relationships with selected insurers, we can help you find the right policy for your needs. Whether you’re looking for home insurance, contents insurance, or gadget and possessions insurance, speak to our team today. We’ll not only help to save you money but will ensure all your valuables are properly protected.

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