Modular Buildings: What are they and who can benefit?

A modular building is one that has been pre built from several repeated sections – modules – to form a completed unit.

In short, this is exactly what a Granny Annexe is – and while the term modular building can make it sound a bit more generic and lifeless, it can also help to explain the different purposes that one of these builds can cover.

What are modular buildings?

Modular construction is the process of constructing a building offsite in a controlled setting such as a factory. The majority of work in creating the building is done in a central location before the building is then transported and assembled in its final destination.

In the case of iHUS’ work, the creation of a modular building takes place at our factory in South Yorkshire. This is where all of the items that make the build are put together such as the frame for the build, the insulation and the finish. All of the items including internal and external walls, the roof and fixtures are created here before being transported across the UK to be put together on the groundworks that have taken place in the customer’s garden.

Building this way is incredibly efficient and there are few limits to the different styles and floor plans that can be created. We’ll cover more on the advantages of modular building later though.

older couple

Once assembled, it is a case of getting the internal finishes right to complete the readied build. In the case of an iHUS build, this will be the kitchen, bathroom, bedrooms and living areas that make your perfect home. The opportunities are endless though, and, as you can see from the people who have benefited in our iHUS community, we have created some incredible homes over the years and changed many lives for the better.

What can modular buildings be used for?

The flexibility and longevity of modular buildings is the key to their success. Not only are they robust and an excellent alternative to the more traditional style of building, the opportunity to do with them as you please means they are viable in so many different industries.

Typically, they may be used for:

  • Housing – such as our granny annexes
  • Office space
  • Retail units
  • Alternative living facilities
  • School and educational facilities
  • Healthcare buildings
  • Sports and leisure facilities

However, we want to know more about homes.

What are modular homes built from?

First of all, let’s look at the groundworks and foundations that are laid before your iHUS home is transported into your property. Foundations are typically screw pile or concrete pad system (depth subject to ground conditions), though a swift plinth system is utilised for all mobile homes built under the ‘Caravan Act’.

This sets the foundations for the outer walls – built using a super-insulated structural timber frame. Marley Cedral Lap weatherboard is our standard cladding, but you can also select untreated green oak for a more natural-looking finish.

Next comes the roof.

Flat EPDM roofing comes as standard though all our annexes can be upgraded with a warm pitched roof finished with a choice of concrete roof tiles and vaulted ceilings in the main living and dining areas.

Internal walls are plasterboarded, skimmed and painted in your choice of colour. Shower room walls are finished with your choice of tileboard. And then there’s the fixtures and finishes… but that’s for another post. You can find out more about the details in our iHUS specification.

Advantages of Modular Buildings

There are many benefits to choosing modular buildings, from efficiencies to cost and sustainable living opportunities.


The quality and finish of an iHUS build is what we pride ourselves on – yet you will also be amazed at the time it takes from confirming your building to the work starting and finishing in your garden. It means once planning has been confirmed your build can be ready in a few short months.


Building off-site in a dedicated factory means that the cost of manufacturing a modular building is reduced. Of course, this means being able to offer the price of buildings to customers at an incredible value.

Less Disruption

With the bulk of the work on a modular building taking place at a dedicated facility – there is less disruption to those on-site, whether this is at an individual’s home or at a commercial property.

Family playing


Using sustainable materials, reducing waste and utilising the latest in green technologies in the finishes and features all play their part in making an annexe or modular building a sustainable opportunity.


At iHUS we offer a 10-year guarantee on all of our builds, yet we know they are constructed to last much longer. A modular building or an annexe should last around 60+ years if not much longer thanks to the quality of its build.

Find out how a modular building can benefit you

Speaking to a member of our team gives you access to a wealth of our knowledge and expertise in the industry. We will be happy to answer any questions you have before booking an initial consultation to understand how you can benefit. Contact the team today.

Recent Projects

iHUS Granny Annexe Bath 1


In Autumn 2020 Wendy Hamm and her family approached iHus as they were contemplating an annexe build in their back garden to house Wendy’s mother. Wendy’s mother Jane, 82, was living over an hours drive away from the family. Wendy’s day to day responsibilities meant that visits to Jane were a lot less frequent then they would have wished. Read their story here.
can i build a granny annexe in my garden

Jean Aldridge

Listed building status lead to green oak cladding and Cotswold stone tiles being used to meet strict planning criteria.
Hot tub outside granny annexe

Ingrid & Donna Giles

Ingrid & daughter Donna Giles opted for a custom designed two-bed annex with large outdoor decked area.
Clarke custom granny annexe

Custom Engineered

This large, two-bedroom custom annexe was finished to an exceptionally high specification, with open-plan kitchen and living area.

Download Your Free Annexe Brochure

Simply fill in the form and you will be emailed a link to download our 32 page annexe brochure.

    Simply fill in the form and you will be emailed a link to download our 32 page annexe brochure. Please check your Junk mail if your brochure doesn’t appear in your inbox

    Request A Hard Copy?:

    Download Your Free Annexe Brochure

      Simply fill in the form and you will be emailed a link to download our 32 page annexe brochure. Please check your Junk mail if your brochure doesn’t appear in your inbox

      Request A Hard Copy?:

      Talk to a Consultant

      We know that building an annexe can seem daunting which is why we created our Signature Move process.

      It all starts with a conversation where we want to get to know you better, understand what you need and give you an opportunity to ask any questions you might have.

      To ger started complete the form on the right and we will get in touch.,,

        Simply fill in the form and one of our consultants will get in touch