Cob construction mortgage

Getting a cob construction mortgage differs from regular mortgages in the UK. So, in this article, we will guide you about the complete cob construction mortgage process.

When we think of how houses are built, we usually picture a standard construction of brick and blockwork cavity walls topped by a slate or tiled roof. Indeed, that is the ideal as far as any mortgage lender is concerned.

Cob houses, on the other hand, are a non-standard construction. So, if you are looking for a Cob construction house mortgage, you could run into some – but not insurmountable – difficulties.

What is a Cob construction house?

Although we now consider brick a standard material for building houses, it is by no means the only material nor the oldest. Thanks to its abundance, simple earth or dried mud have been used to fashion free-standing dwellings.

Mix the earth with equally available straw, and you get a building material that is robust and long-lasting with good load-bearing capabilities. That is the material in English called Cob or Cobb.

Cob houses have been around in England for a very long time. Some of the earliest date from the 13th -15th century and until the dawn of industrialisation in the 18th and 19th centuries, Cob houses were the norm. As a result, the Cob construction house is an architecturally significant design in English social history.

Construction method

Designing Buildings website outlines the basic construction methods adopted for Cob houses.

The foundations of the building are laid by stamping down on the mixture of subsoil and straw that makes the Cob. The foundations are typically around 11 to 12 inches wider than the walls and must be deep enough to take their load.

The Cob mixture is then laid in courses to build up the walls, and each course must dry out completely before the next course is laid. The walls are steadily built up and taper inwards slightly to increase their load-bearing capacity, making it possible to construct dwellings of two storeys. Curves and other fluid and organic shapes can easily be incorporated into the Cob construction.

Windows and doors can be built into the structure using simple lintels as the walls go up, or they can be cut through the Cob walls after they have been built.

Cob construction is surprisingly energy efficient – the thick walls (usually at least 2½ inches) retain the heat when it’s cold outside and keep the inside cooler in the hot weather. Indeed, the U-value of a Cob wall – the measure of its insulating effectiveness – is typically better than in modern buildings of standard construction.

The roof of a Cob house typically has a broad overhang to protect the walls from the rain and damp. The overhang is generally at least seven inches. If cracks do open up in the walls, though, they can be quickly filled with fresh Cob mixture.

Cob construction was most popular in the southwest of England, but it also spread to East Anglia and the rest of the country until this building technique largely disappeared by Victorian times.

Environmental benefits

Cob construction is currently enjoying something of a renaissance, with even commercial builders showing an interest.

That is because of a renewed interest in the sustainability of Cob construction materials and methods – making them both economically attractive and environmentally friendly. Subsoil, straw, water, and a little sand are readily available in practically any location after all.

These considerations have also prompted interest from self-builders who can cut down on the expensive labour costs of building their home and the need for the power tools otherwise employed for more conventional building methods.

Can I get a mortgage on a Cob house, and why might it be difficult?

For all the attractions that might make Cob houses currently more environmentally friendly, the fact remains that they are non-standard construction – and, as we noted from the outset, mortgages for homes of the unusual structure are more challenging to obtain.

Although it may be possible to secure a Cob construction house mortgage, this will be based on it being a non-standard construction mortgage – just as similar alternative construction materials such as straw bales, concrete panels, or wattle and daub will also be classified as non-standard construction by a mortgage lender.

How do Cob mortgages work?

Regarding the formal application process, Cob mortgages differ very little from any other mortgage application. Any lender will need to consider the condition and value of the property you want to buy and the affordability of the loan you are requesting.

That will mean assessing the affordability of the mortgage with reference to your present and future earnings, your outgoings, and any other loans and open lines of credit. Your credit history will be scrutinised to see how well – or otherwise – you have managed previous debts.

Your biggest challenge, however, lies in finding those relatively few lenders prepared to advance the loan you want as a non-standard construction mortgage. Because the pool of available lenders is more restricted, you might want to make an early start by consulting a broker with expertise and experience in such matters.

Next steps

Cob houses have a long history – many are still standing, and new ones are being built in response to what are seen as the environmental benefits of building this type of dwelling.

Identifying a lender prepared to advance a Cob house construction mortgage, though, might prove more complicated. Therefore, you might want to consult independent experts such as ourselves here at so that we can point you in the most likely direction and assist you throughout the formal mortgage application process.

Damian Youell

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Can I get a mortgage on an unusual construction property?

Yes, you can get a mortgage for unusual construction in the UK but you may need to contact a specialist mortgage broker before starting your mortgage application process.

Why is getting a non-standard construction mortgage more difficult?

It’s not always easy to find a lender willing to offer a mortgage for a non-standard construction property. This is because there are fewer lenders offering mortgages for these properties than for standard construction. The reason for this is that the risk involved in lending money to someone who has chosen to build a non-standard construction home is greater than for someone who has built a standard construction home. It is therefore important that you seek advice from a mortgage broker who specialises in helping people to get mortgages for unusual construction properties.

How Do You Get a Mortgage for a Prefab House?

In the Uk, prefab homes are mostly associated with the prefabricated houses built in the years of the second world war to provide temporary housing facilities. However, today, prefabs are used for both residential and commercial purposes. They are usually constructed using steel frames which are then covered with cladding materials like brick, timber, glass etc.