Non-standard construction: what homeowners need to know

Modern homes are typically built using brick or stone walls with a slate or tiled pitched roof. However, many properties across the UK feature alternative, historic, or specialist construction methods. These homes are often classed as non standard construction. While this doesn’t pose a problem for most homeowners, it does mean insurers will assess the property differently to ensure the cover reflects its specific risks. This guide explains what non standard construction means, why it matters, and how various construction types are treated by insurers.

What is non-standard construction?

Insurers have their own definitions, but most consider standard construction to be:

• Brick or stone walls
• A tiled or slate pitched roof

A property built using alternative materials or techniques may fall under the definition of non‑standard construction.

Why does it matter to insurers?

Home insurance applications ask about your property’s construction so insurers can assess the level of risk, calculate the premium, set appropriate terms and determine what cover is available.

Insurers general prefer standard construction because of the wealth of claims statistics which makes future claims more predictable. With non-standard construction, insurers may need to factor in:

• More complex or costly repairs
• Specialist materials or contractors
• Longer repair or rebuild times
• Greater susceptibility to certain types of damage

Because of this, insurers may apply higher premiums, increased excesses, specific conditions, or request surveys on ongoing maintenance requirements.

Longer rebuild times, difficulty sourcing materials, and the need for specialist skill all contribute to the increased cost of reinstating non-standard properties.

It’s also important to provide accurate information. If an insurer discovers incorrectly disclosed construction details at the time of a claim, they may:

• Refuse to pay the claim
• Charge an additional premium retrospectively
• Cancel the policy altogether

Types of Non-Standard Construction

Below are some of the most common forms of non standard construction and how insurers typically approach them.

Timber frame (lathe and plaster)

Timber‑framed properties are among the most common types of non‑standard construction. Insurers usually focus on the infill material and the age of the building when assessing risk.

Older timber‑frame homes often feature lathe and plaster - thin timber strips fixed to a frame and coated in plaster. This traditional method is more vulnerable to fire, water damage and vibration than brick or stone, but it is still widely accepted by insurers and may even be considered on similar terms to brick.

Modern timber‑frame properties typically use brick or stone infill, which is generally accepted without issue, provided the construction is disclosed. In most cases, the infill material, rather than the timber frame, drives the insurer’s terms or rating.

Wattle-and-daub

Wattle-and-daub consists of a timber frame with woven timbers (the wattle), coated on both sides with a mixture of mud, straw, water, and historically, dung (the daub). Once dried, it forms a wall structure.

Although generally acceptable, insurers factor in increased risks such as:

• Higher fire risk
• Susceptibility to mould
• Erosion or cracking of the daub
• Specialist repairs required using traditional methods

These factors can influence both the likelihood and cost of a claim.

Steel or metal frame construction

Steel or metal-framed homes are assessed partly on their infill material but also carry additional considerations.

Key risks include:

• Corrosion, especially if untreated
• Difficulty detecting early subsidence

Because of these factors insurers may request a structural survey..

Cob construction

Cob is a mixture of clay, sand, straw and water, layered to form an unfired earth walls. Repairs must be carried out using traditional techniques, which can be lengthy, labour intensive and require specialist skill. Availability of suitable materials also varies by region.

Cob buildings are particularly susceptible to:

• Damp and moisture
• Water ingress
• Erosion, vegetation growth, and wildlife activity
• Water pooling at the base of the walls

These events highlight vulnerabilities in practice. In Devon, a historic 17th century pub, suffered a catastrophic collapse when an entire cob wall gave way after a night of heavy rain, with water believed to have penetrated a pre existing crack and destabilised the structure1. Likewise, in Dorset, the gable wall of a pub collapsed without warning, with inspections revealing “historical defects and deficiencies” in the structure2. These incidents demonstrate why insurers carefully assess moisture risks, hidden defects and structural disturbance.

Bungaroosh

Found predominately in Brighton and Hove between c.1750 and 1900, Bungaroosh is a mix of gravel, sands, flints, broken bricks and cobble stones bound in a lime solution. It is often found in party walls, rear walls of terraced houses, and garden walls, so may form only part of a property’s structure. Bungaroosh:

• Absorbs moisture easily
• Can weaken significantly if water gets behind the render,
• Requires prompt specialist lime-based repair.
• Varies In composition from wall to wall, making behaviour unpredictable

Insurers therefore need to consider this, as it influences both the risk and potential claim outcomes.

Huf Haus

Huf Haus properties are a premium, prefabricated home manufactured in Germany, then shipped and assembled on site over a matter of weeks. Insurers factor in:

• The costs of production and shipping
• Need for specialist repair and rebuild
• The extensive use of glass, influencing reinstatement costs,

Not all insurers will accept this construction type, but discussion with our high-net-worth panel can help identify suitable cover.

Flat roof construction

Most insurers ask for the percentage and material of any flat roofing, as flat roofs typically carry higher risks than pitched roofs. Concerns typically include:

• Water pooling
• Storm damage
• General wear and tear

Many policies include maintenance clauses requiring flat-roof areas to be inspected every few years.

Failure to maintain or to disclose a flat roof may result in declined claims, particularly for ingress of water or storm damage.

Tips for Homeowners

Finding the right insurer is important if your home is considered non-standard construction. As long as you provide accurate details about your property, you should have confidence that your cover is appropriate. Remember to:

• Submit survey reports if requested by your insurer
• Keep a record of your home’s maintenance
• Use specialists where required, particularly for traditional or complex materials

Navigating non standard construction insurance can feel complicated, but you don’t have to manage it alone. We work closely with homeowners to ensure their property is properly understood, accurately presented to insurers, and protected with the right level of cover.

To speak to use about your home insurance, call 020 8256 4901 or email privateclients@howdeninsurance.co.uk