How to tell whether a prefabricated build is right for your project
There are advantages to having your home built in a factory. A modular home can be completed faster than traditionally constructed ones, and offer a high level of quality and sustainability. Without the potential disruptions of building on site, the components are assembled efficiently, with minimal waste. ‘In the 21st century, when cost is everything and we need to lower carbon, building in a factory gives a lot more control,’ says Dick Shone, founder of Boutique Modern.
There are two main types of off-site construction. The first, typically known as kit homes, includes buildings where the components are prefabricated, creating a series of parts to be assembled on site. It’s essentially a flat-pack home. But the term modular usually refers to houses that are entirely built in a factory and delivered to the site in completed sections with bathrooms and kitchens in place. This more streamlined process is also known as volumetric construction. An entire house can be made out of three or four modules that are craned into place.
Most modular companies specialise in off-the-shelf designs, while others offer a more bespoke service where you can either customise a standard template, adapt a design the firm already has planning permission for, or start from scratch.
1. Access is everything
Location is the most important factor when assessing whether a modular home is feasible. ‘Can you get a crane to the site to deliver the house?’ asks Dick Shone. No plot is impossible, but narrow lanes or restricted access can make things harder, which will add to costs. For hard-to-reach sites, a kit home may be a more affordable solution.
2. Select the right supplier
It’s important to choose a manufacturer suited to the type of house you want. Most of them specialise in a particular system, whether that’s cross-laminated timber (CLT), structural insulated panels (SIPs) or light-gauge steel frame. ‘There’s a massive range in what firms are offering,’ says Wilf Meynell of architecture practice Studio Bark. If you are unsure which to choose, Wilf recommends consulting an architect with experience in modular building before committing.
3. Sustainability is not guaranteed
While most modular houses offer impressive levels of energy efficiency once built, some are made from materials sourced from abroad, giving them high embodied carbon. To find the most sustainable approach it’s a good idea to compare the claims of a few different manufacturers. ‘Embodied energy is quite a complex thing to calculate,’ says Wilf Meynell. ‘But I think one of the key things is that we have to move away from petrochemical-based materials, towards natural products, recyclable options and things that are compostable.’
4. There’s plenty of room for imagination
Just because a house is prefabricated doesn’t mean it has to look like it came from a catalogue. While kit homes are not generally that adaptable, a modular building can be created to almost any design. It’s also possible to take an existing design and adapt it for off-site construction after it has planning permission. ‘A modular company can pick up a scheme at any stage in the process,’ explains Dick Shone.
5. Modular doesn’t come cheap
Prefabrication is often more expensive than on-site construction because it offers a higher standard of quality. ‘There is a misconception that this is the cheapest way to build,’ says Theo Dales of Koto. But there is a lower risk of costs escalating once construction is underway. The most important thing to be aware of is that the price quoted for the modular home by the manufacturer doesn’t cover everything. You still need to buy the land and there can be other costs to factor in too – not all companies include groundworks in their packages.