22 October 2025 | Written by Mercantile Trust

Broker Guide: Lending on Non-Traditional Property Constructions

As a broker, you’ll know that not every property fits the standard brick-and-mortar model. Across the UK, thousands of homes and investment properties were built using non-traditional construction methods, many of which were introduced after World War II to meet housing demand quickly and economically.

While these properties often offer good value and strong rental potential, they can face limited lender appetite — especially when flagged as “non-traditional” on a valuation report. At Mercantile Trust, we look beyond the label and take a pragmatic, common-sense approach.

What Is Non-Traditional Construction?

Non-traditional construction refers to any property not built using conventional brick or stone walls with a tile or slate roof.
These properties use alternative materials or structural methods that differ from “standard construction.”

Common examples include:

Concrete Constructions

Precast reinforced concrete (PRC) – Post-war housing such as Airey, Cornish, and Wimpey No-Fines types.
In-situ concrete – Cast on-site, often used for larger blocks or developments.
Concrete panel systems – Prefabricated sections assembled on-site.

Steel-Frame Constructions

Homes built with a steel structural frame supporting walls and roof.
Seen in mid-century housing and modern modular designs.
Durable when maintained properly, though some lenders restrict due to corrosion concerns.

Timber-Frame Constructions

Older timber-frame homes can be historic and highly valued.
Modern timber-frame properties are popular in new-build developments for their efficiency and environmental performance.
Despite their quality, they’re often still classed as “non-traditional.”

Other examples can include:

Aluminium or metal-frame builds
Modular or system-built homes
Prefabricated post-war houses
Structural Insulated Panels (SIPs) or Insulated Concrete Formwork (ICF)

Why Some Lenders Hesitate

Many lenders remain cautious with non-traditional properties due to:

Concerns about durability and resale
Historical maintenance or insurance issues
Valuation complexity or limited comparable data

However, these challenges depend heavily on the specific property, construction type, and condition — not just the classification.

Mercantile Trust’s Approach

At Mercantile Trust, we’re happy to consider all construction types, including every variation of:

Concrete
Steel-frame
Timber-frame

If the property is flagged as non-traditional on a valuation report, that’s fine.
As long as it’s suitable for the area, structurally sound, and acceptable to the valuer, we’ll usually take a look.

We use manual underwriting, assessing each case individually rather than relying on automated systems. Our goal is to understand the story behind the property — not just the structure.

Key Features

Up to 75% LTV
1st & 2nd charge Buy-to-Let and Bridging loans
AVMs possible on non-standard construction
(excludes Purchases, MUFBs, and Holiday Lets)
Drive-by valuations available up to 65% LTV

What This Means for Brokers

You can confidently refer clients with non-traditional builds.
We’ll assess each case on its own merits, not reject it based on construction alone.
You’ll get direct access to experienced underwriters who understand specialist property finance.

Whether it’s an ex-local authority PRC home, a steel-frame flat, or a modern timber-frame house, we’ll look at the whole picture to help your client secure the funding they need.