Things to consider when you are thinking of building an Annexe – Design, Planning & Build

Where do iHus build?

We build in England and Wales.

Where can I build an annexe?

An annexe must be built within the curtilage (garden) of a main property. It is classed as an ancillary dwelling, in simple terms it means it is connected to the main dwelling, sharing its services, address and access.

Do I need planning permission?

The simple answer is yes. An annexe is a residential dwelling so planning permission is required, and we would handle this on your behalf. We work alongside NAPC, the UK’s only annexe and garden room planning and development consultancy. Applying for both a householder application and a certificate of lawfulness, also known as the caravan act. Our dual approach gives you best chance of gaining permission, we currently have a 94% success rate.

How long does it all take?

We will prepare and submit the application to your local planning authority (LPA). Once validated, which can take up to 4 weeks, the planning application process takes 8 weeks. Then the build itself, depending on the size and specification you choose takes between 8 and 12 weeks.

Can I change the layout of your annexes?

Certainly, all the internal layouts of our core models can be changed, or we can start from scratch if you have your own design in mind. We do not build two story annexes, and we do not convert existing buildings.

Are there any size restrictions?

An annexe cannot take up more than 50% of the garden and cannot be bigger than the footprint of the main property. Under the caravan act we can build up to 20 meters by 6.8 meters.

What foundations do you use?

Ground screw piles are an eco-friendly and innovative foundation solution, offering several advantages over traditional concrete footings.

How is the annexe built?

The timber structure is built in our factory in South Yorkshire in cassette form, then delivered to site and constructed.

What access do you need?

We need a meter width access. We can access your garden through a garage or a side gate, but we cannot go through the house. We require access for the full duration of the build, as deliveries will be made directly to the property.

Do you connect the services?

Yes we do, water, electricity and sewage. We do not use gas.

I’m not on mains sewerage, will this be a problem?

Not at all, we can connect to a septic tank instead.

Do you fit solar panels?

Yes, we have packages for all our core models, both flat and pitched roof options. Solar panels are included on our contemporary (Pent Hus) models as standard.