Building a Granny Annexe – Our Process from Start to Finish

One of the greatest reasons to choose iHUS to build your granny annexe is that we manage the entire process from start to finish. We look after every single aspect of your project including planning permission. Read on for more details about our granny annexe process.

What Does the Granny Annexe Process Involve?

Building a granny annexe is a big project to undertake – choosing an annexe, getting utilities sorted, preparing the site where the annexe will be situated. Then there is planning permission to contend with. If you had to manage each of those tasks yourself and use separate companies, you might quickly be put off building a granny annexe.

The good news is that here at iHUS we provide a complete end to end service. We remove the headache from the process and make it as easy as possible for our customers to achieve the annexe of their dreams.

image shows as smiling older couple

iHUS are in a unique position because we not only manufacture our own high-quality modular annexes, we also install them, complete all groundworks and help with planning permission.

Our simple six step process demonstrates this:

Step 1 – getting in touch with us is easy and we have experts on hand to answer any initial questions that you may have. A quick chat with one of our friendly team members will give us a better idea of what you are looking for and we can also let you know how we can help.

Step 2 – after initial contact we will visit you for a free onsite consultation. During the consultation, we will assess your garden and its suitability for an annexe and run through the option with you. Our consultant will go into detail about the different styles of annexe we can provide, the finished you can choose and explain planning permission. Budgets will also be discussed so that we can get a better idea of what you want to do.

Step 3 – after our consultation, we will draw up a detailed plan of your annexe and provide everything you need to make a decision and move forward including;

  • The process of obtaining planning permission
  • The warranties and build guarantees
  • Project timelines and what to expect
  • The annexe build specifications
  • A full set of footprint and elevation drawings of your annexe
  • The fees required for the build permission application
  • A detailed cost breakdown
  • Any extra costs for additional works
  • The payment schedules for the build

Step 4 – we start the process of applying for planning permission immediately after contracts are signed. We work with industry specialists to ensure we stand the best chance of obtaining permission to build your annexe. On average it will take between 8 and 13 weeks to receive the decision back from your Local Planning Authority.

Step 5 – During the entire process, you will have a single point of contact to ensure that you are always kept updated. Your project manager will be your go-to person for any questions you have.

Step 6 – the most exciting part of the process is seeing your annexe become a reality. Our team will be working in your garden completing groundworks and sorting out utility’s connections, once that is complete, your new annexe will be delivered and assembled. Once the final touches have been completed its time for us to hand over the keys and you to move into your new home!

image shows a family that have completed the granny annexe process and are celebrating with a drink

How Long Does the Process Take?

Once a plan and design have been signed off, the granny annexe process timeline depends on the size of the annexe, any complexities presented by your site and planning permission.

On average, our more compact annexes take around 7-8 to complete and a small two-bedroom annexe will take 8-11 weeks. So, including planning permission, you are looking at an average project time of 5-6 months. This is from sales consultation to having the keys in your hand.

You can read about the project timelines in more detail here.

Get in Touch

Why not take advantage of our free onsite consultation? We can run through what you are looking for, survey your garden and give you a more accurate idea of what your project will involve and how long it will take.

Please get in touch using our contact form.

View Our Annexes

The Cantley is the smallest annexe in our Core range and is one of our most popular models for independent living. The floorplan is designed to maximise space and fits comfortably into most back gardens.
As one of our most popular one-bedroom annexes, the Bawtry is the perfect choice for elderly care or an independent young adult looking for their first home.
The Ravenscroft is a spacious one-bedroom annexe, designed for those with a larger garden plot. All three footprints utilise a central shower room to separate the bedroom and the open-plan kitchen/living area to maximise living space.

Recent Projects



This idyllic annexe is home to Theresa and Austin situated at the bottom of their daughter and son in law’s garden. Having always lived very closely to one another, the family were convinced this way of life wasn’t going to end anytime soon, & their wonderful annexe has made this a reality!
Speedwell Annexe


Our customer moved into her Annexe in January and is thoroughly enjoying her lovely new home. She describes her Annexe as ‘Warm Sunny Cosy & Comfortable’. Click below to watch an exclusive interview with the owner and watch their Annexe walk through!
Williamson bespoke granny annexe

Jenny Williamson

The Williamsons family moved into their Annexe over 3 years ago. When visiting the family they told us life in their new home exceeded their expectations for many reasons. So much so, they wanted another iHus building! Click view to find out more about their story and take a look around their Annexe.

Wendy Hamm

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.

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 get started complete the form and a member of our team will get in touch to book you an appointment with a consultant…