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Portable Cabins vs. Modular Buildings: Finding the Perfect Prefab Solution

Prefab construction offers a versatile alternative to brick-and-mortar buildings. With all elements pre-made ahead of construction (prefabricated), you’re saving time and getting a building you can use far quicker than the traditional alternative. It also works well when it’s just one structure you need, such as an office, accommodation, or a classroom.

When it comes to classrooms, schools often opt for one of two options: portable cabins, or modular buildings. But what’s the difference, which is better for you? And is there an alternative?

Portable cabins: A speedy space solution

Portable cabins, also known as ‘mobiles’, are usually a compact, self-contained unit delivered and, once connected to utilities, ready to use within a day. Perks of portable cabins include:

  • Immediate occupancy: The speed of implementation makes them useful for contexts requiring spaces immediately, like a temporary office for a construction site, or schools requiring emergency classroom solutions.

  • Portability: As the name suggests, they’re portable too, meaning you can relocate them as needed. They can be easily disconnected from utilities and moved to a new location when your needs change.

  • Lower (initial) costs: The cabins themselves usually have lower monthly costs than modular buildings. However, you do need to factor in significant additional costs for: foundations, services and delivery; rental for the duration of the cabin’s life; and eventual removal of the cabin/reinstating of the site.


Portable cabin drawbacks?

Portable cabins work well for temporary needs, but as such will struggle if you intend to use them for the long term. They are built with lighter materials than modular buildings for ease of transportation, but this also makes them less durable both for harsh weather conditions and the test of time. Damp and mold, for example, can plague portable cabins used for too long.

They are also typically smaller and have fewer design customisation options. They’re less likely to satisfy those looking for sophisticated or bespoke design. If your layout is complex or you need a large scale building, portable cabins may not fill the bill. Portable cabins also tend to have limited amenities. Plumbing and electrical systems are often basic, and extensive customisation options for things like insulation or climate control might be limited.

Installation also isn’t as simple as placing a portable cabin on your site in a day. Enabling works are required, which means preparing the build site and laying foundations. For a typical single portable cabin classroom, the up-front costs for this preparation and installation could be £25-30k, if not more. You also have to remove the building at the end of its lease (portable cabins are mostly rented, rarely owned outright (which is an additional cost to consider), and will need to pay for those haulage costs too. So there is a perceived simplicity but complexity remains.

Modular buildings: Scalable space for the long term

Modular (or ‘sectional’) buildings are constructed from individual sections (modules) that are bolted together on-site. They function like flat-pack furniture on a much larger scale. They offer:

  • Scalability and flexibility: Modular buildings consist of multiple interlocking units, which allows for creating a larger space by combining modules. If you need a single or double classroom, or something even bigger, modular buildings handle all of these contexts well. The modular design offers flexibility to reconfigure the layout in the future, if needed.

  • Durability and permanence: Constructed with sturdier materials and designed for long-term use, modular buildings can withstand harsher weather conditions and provide a more permanent feel, even in a temporary setting.

  • Greater design options: With modular buildings, you have more freedom to customise the layout, including features like multiple stories, larger windows, and improved insulation. This allows for creating a more comfortable, functional and visually appealing space.

  • Amenities: Modular buildings can be outfitted with a wider range of amenities, including advanced plumbing, electrical systems, heating, ventilation, and air conditioning (HVAC). This makes them suitable for uses requiring a more complex and comfortable environment.

Modular drawbacks?

Because of the advantages of size, flexibility and durability, modular buildings tend to come at a higher up-front cost vs portable cabins. They take longer to set up, because portable cabins arrive ready-built whereas modular buildings are made on site (although they can still be ready in a matter of weeks – far quicker than traditional construction). They’re also less mobile as they‘re intended for more long-term scenarios. If you need a low cost, temporary space as soon as possible, and your needs are more basic, a portable cabin is probably the better fit.

The enabling costs of haulage installation and laying foundations (that apply to portable cabins) still apply to modular buildings, though they are offset in this case by the long-term lifespan of modular buildings vs portable cabins. However, modular buildings still come with restrictions. Since they rely on pre-made modular components, the sizes of said components is fixed which can limit construction options. The building is ‘sectional’, composed of parts joined together, and incorporating these joints into the structure can create challenges. These sections make it easier to disassemble a building should you need to, but limit the space you can create too. So modular buildings offer more layout options than a traditional portable cabin (which is a fixed size, designed to fit on the back of a lorry) but limitations remain.

Exterior view of Vertis modular classroom at a primary school

A third way: Bespoke architecture

So, both modular buildings and portable cabins come with benefits and drawbacks, and suit different contexts. What about a third way? At Vertis, we use an approach that builds on the strengths of modular buildings but overcomes their limitations – and that’s the bespoke architecture route that we use for almost all of our builds. We employ modular processes, particularly the use of Structural Insulated Panels (SIPs), but we don’t make ‘modular buildings’. Apart from SIPs all components are built specifically for your building, made to measure. That means we can create a space that fits exactly to what you need. We also build something that’s not made to be moved. This gives your building focus and permanence, because you don’t have to build something ‘sectional’ that can later be deconstructed. Rather you get to build exactly the space you need, with the design features that you’d like, made to last for the long term. We find that for many schools, that’s what they need from a classroom or learning space – they’re not just looking for a short-term solution. Our bespoke architecture is made with the speed and efficiency of a modular building (ready in as little as 8 weeks) but with the freedom, precision and longevity that modular buildings and portable cabins lack. You can see the classrooms and learning spaces we’ve made for schools here.

Ultimately your own context and needs are the most important thing and should determine your building choices. But maybe it’s unclear what you need or what your options are – the best way to find out is to have an expert come to your site and look at your situation. Vertis offer a free consultation where we come to your school and see what you’re facing and what you’re looking for. You get a free site survey and our ideas and advice, no strings attached. Get in touch here if you’re interested.