The simple answer to this common question is yes! There should be no issue getting a mortgage on a modular or prefab extension. As long as the system you choose is an approved, accredited and trusted system(such as the hup! prefab building system), you should be able to secure a mortgage to build your extension in the same way that you would if you were building with bricks and mortar.
Let’s explore this topic further – as house prices rise and families outgrow their homes, many homeowners are choosing to adapt their existing home with the addition of an extension, rather than face the huge expense of moving. Prefab or modular extension systems can typically offer a smarter, faster, and more energy-efficient alternative to traditional construction.
The hup! system is a prefabricated extension system that is the perfect example of a better way to build for many reasons:
- 5X more energy efficient than the average UK home
- 5X faster to build than bricks and mortar
- Complete design flexibility – windows, doors and walls anywhere you want in the design
- Minimal mess and disruption compared to a traditional build which uses concrete
- A perfect build every time – 100% pre-fabricated so no cutting on site
As you can see, building with a prefab system such as hup! offers immense benefits vs building with traditional methods – and its many benefits explain why, for the purpose of a mortgage, there is no issue with building your extension with hup! or another prefab or modular building system.
So, what is the difference between a modular and a prefab extension?
Modular or prefabricated (prefab) extensions are both built off-site in a factory and then assembled at your property. Unlike traditional brick-and-mortar builds, they’re manufactured under controlled conditions, which means faster timelines, fewer delays, and often better energy performance. These types of extensions also don’t typically suffer from weather delays as they can be built in any weather.
The key difference is that a prefab extension system is a system where individual components, such as the walls and roof, are manufactured off-site and then brought together on site to be assembled into an extension. With a modular extension, entire rooms or modules are fully assembled in the factory and arrive on site as a complete room with walls and roof, and often other components within already in situ, such as plasterboard and even kitchens and bathrooms. Prefab extensions are still essentially bespoke, and allow for huge design freedom, while modular systems are often more limited in terms of design choices.
As hup! is a prefab building system, it offers complete design flexibility – no different to if you were constructing an extension from bricks and mortar – but without the drawbacks that traditional building methods can bring to a site.
This table explains the differences between prefab and modular extensions at a glance:
| Modular Extension | Prefab Extension (eg hup!) | |
| Design flexibility | Limited | Extremely flexible |
| Construction method | Full modules/rooms are bolted together on site. May already include plastering/electrics | Offsite manufactured components such as walls, roof etc are assembled/built on site |
| Faster than bricks & mortar? | Yes | Yes (hup! extensions are constructed from DPC in less than a week) |
| Less mess than bricks & mortar? | Yes | Yes |
| More energy efficient than bricks & mortar? | Can be | Can be (hup! is 5X more energy efficient than average UK home) |
Securing a mortgage on a modular or prefab extension
Mortgage lenders tend to prioritise quality, safety, and the value added to your home when assessing a mortgage application for a home extension – and there is no reason why a modular or prefab extension should not meet all of these requirements.
Here are a few key factors lenders will consider if you are planning to add a modular or prefab extension to your home. (These are the same factors they would consider if you were building an extension from traditional methods such as bricks & mortar):
- Property Value Impact: Most lenders will assess how the extension will increase your property’s value. With a hup! extension, you’re not only adding space — you’re improving energy efficiency and aesthetics, which can significantly boost resale value.
- Quality: The materials used in the construction of your extension must comply with Building Regulations and be of a high quality. (hup! walls and roofs are pre-approved for Building regulation compliance and have been given the maximum life expectancy by the BBA of 60+ years for their longevity -an indicator of quality).
- Structural integrity: Lenders want to be assured of the structural integrity of any extension and may request data when it is a modular or prefab extension. With hup!, the wall panels are 68% stronger than a brick wall thanks to the collective force of the panels, which rapidly clip together to form a super-strong i-beam structure.
Alternative ways to finance a modular or prefab home extension
You may not need a traditional mortgage at all. Many homeowners finance modular or prefab extensions through:
- Remortgaging to release equity
- Home improvement loans
- Personal loans
- Green loans (increasingly popular for energy-efficient builds)
In summary
Yes — you can get a mortgage or financing on a modular or prefab extension. Speak to your mortgage provider early in the process to find out how much is possible and get an up-to-date property valuation first. Make sure you choose a trusted system that is Building Regulation compliant and with accreditation from external agencies such as the BBA. This demonstrates the quality and performance of the system.
In summary, choose an approved, accredited and trusted system such as hup! to ensure your build meets lender expectations — and exceeds your own.
