Frequently Asked Questions About Granny Annexes

Do I need Planning Permission for a Garden Annexe?

In most cases you will NOT require planning permission if:

a) your annexe is *demonstrably* movable (of course, all our garden annexes comply)
b) the annexe will be used by a close member of the family

However, in many cases, you will require planning permission for many other types of annexe, and doubly so if the Annexe is not for a close member of the family.

We complete an application for a Garden Annexe for our clients on a weekly basis. There are convenient areas of legislation that enables us to ensure the Annex qualifies as Lawful Development rather than requiring full planning permission.

Lawful Development is relevant when the Annexe is designed to comply with legislation that acknowledges the genuine movability of the Annexe itself combined with the circumstances if the Annexe is for a close member of the family.

In such circumstances, when the Annexe is for a member of the family, we can prove each annexe is demonstrably movable, meaning that the Annex is considered to be a chattel or a “good”. In these cases, we will submit to your local authority that your Annexe is lawful and planning permission is not required in these circumstances are lawful. A Development Certificate is typically granted by the local planning authority once they are confident that there is no material change of use and that there is no operational development.

Importantly, a Lawful Development Certificate submission does not involve neighbours or parish councils or other third parties and therefore provides each householder with a less complicated validation for the lawfulness of their Annexe. Our planning service covers both planning permission and lawful development so we can advise each client which may be most appropriate.

In 90% of cases an LDC is more than sufficient to provide suitable comfort for the householder.

Are Garden Annexes double glazed/insulated?

Yes. All our garden annexes are fully double glazed and fully insulated being designed for year-round residential comfort, no matter the weather. High specification double glazing is important in the winter and in the summer to provide a comfortable interior throughout the year. We specify 100 mm of Celotex Insulation providing excellent installation characteristics.

What materials are used in a Garden Annexe?

A Garden Annex is only as good as its design, its installation and the materials used to reinforce the nature of the structure to be used for full time living accommodation. Our annexes are constructed from heavy duty glulam timber frames which are individually CNC machine-cut and to a tolerance of 0.1 mm we use a fire retardant lining which gives a nice warm plaster effect internal finish and full 100 mm of Celotex insulation in the floor, the walls and the ceiling to ensure the Annex is cool in summer and warm in winter the annexe is sheathed in 18 mm OSB and 9 mm OSB for structural integrity.

The Annexe cladding is completed with the use of MTX. A unique timber composite panel that is designed specifically for these applications. The cladding is coated with Owatrol solid colour stain which does not require re-coating for at least 10 to 12 years. Mono pitched roof annexes arrived with a one piece, EDPM rubber sheet which provides 25-year coverage and complete peace of mind. All windows and doors are complete with black satin exterior finish, full double glazing and category A certification. Each wall of the Annexe is 222 mm thick, which is approximately 9 inches, to give a solid and robust structure for comfort all year round and a minimum 40-year Design life.

Are Garden Annexes suitable for disabilities?

Yes. All our annexes are readily adaptable to accommodate many disabilities with ramps, wide aperture doors and wet rooms to facilitate suitable disabled access. As each Annex is specified individually at the site survey stage, it means we can configure the design of your Annex to suit your requirements exactly.

What are the advantages of a modular Garden Annexe?

Our Garden Annexes are individually designed and manufactured at our state-of-the-art factory in Suffolk, with each component machine-cut to .1mm so we enjoy a quality and a precision finish that is unsurpassable. Every element is assembled on site by our dedicated, well-trained, in-house (not sub-contractors) technicians meaning that there’s no inefficient and wasteful cutting whilst on-site.

Are you Specialists ?

Yes.
We only produce Garden Annexes and complete the entire service. It means we remain focussed on supplying a great service, and you a enjoy a lovely new home. All our team are full-time and PAYE so we remain in control of the process throughout and are reliant on “subbies” .

Do you provide the full service?

Yes. Happily!

How do I insure a garden annexe?

We recommend that your Garden Annex is separately insured on the existing household policy. This prevents complications with the insurers who may have a concern about who is the beneficial owner of the Annex. In many families, a simple annual payment is made by the Annex user to the main householder.

How is electricity metered in an annexe?

The electricity consumed within the garden. Annex will still be measured at the main household electric meter. However, in some cases we will install a sub meter into the Annex itself so that the exact electrical usage can be individually measured, and a payment agreed between the Annex user and the main householder.

Will a garden annexe affect my water pressure ?

No.

Your annexe will encounter exactly the same water pressure as you experience within the main house, without notable reduction in pressure with the annexe in place.

Do you use groundscrews with a Garden Annexe ?

Unless we are operating in close proximity to trees with preservation orders. We will normally avoid using Groundscrews in a typical Garden Annexe installation.

Normally we install a full heavy duty concrete lattice base which is 300 mm deep and 300 mm wide beams. The base is cast on site with the concrete delivered into the shuttering via pump and volumetric delivery. A concrete base provides a considerably improved solid and structural footing on which the Annex will stand and ensures the removal of any bounciness associated with Groundscrews.

What is a Garden Annexe?

Separate living accommodation for members of the family

Typically from 4m x 3m to 8m x 5m in size

Manufactured offsite and instantly installed in a domestic garden

Specifically created as a living space - not merely as a “garden room”

Normally assembled in the garden - but can be craned into location

Warm, safe, comfortable and attractive

Do I need planning permission for a granny annex?

Yes and No.

Yes: if you seek to build a traditional granny annex then you will require planning permission.

No: if you seek to have a hybrid Granny Annex (one that can moved in one or two pieces) installed then planning permission, in most locations, is not required for a such a structure - as it is fully movable. We recommend that it is a good idea to get a Certificate of Lawful Development though, just for your peace of mind.

What is a Lawful Development Certificate?

A lawful development certificate is a legal document that is provided by a local planning authority, local authority or council on this certificate proves and acknowledges the lawfulness of any development, such as a suitably specified garden Annex when combined with its use by a close family member of the house of the main householder.

We undertake a submission for a lawful development certificate on a weekly basis with local planning authorities across the UK.

We provide a 23 page document to support the submission in every case, and we justify the submission by proving the movability of the Annex and that the Annex is for use by a close member of the household as family, it’s important to note that many local authorities no longer except applications for sips based annexes to be considered movable whilst our hybrid timber framed annexes readily provable in terms of their movability.

Once constructed on site, we have video evidence and structural engineers’ drawings to validate the individual movability by means of crane and hoist of each Annex, no matter its location. This means that most Garden Annexes that we produce do not require planning permission due to their unique construction system and their intrinsic movability.

What’s the difference between a garden annexe and a garden room?

A garden room is typically a lightweight timber structure installed in a domestic back garden which is normally used as a home office, leisure space or man-cave. Garden rooms are great for part time and incidental use and in most cases do not require planning permission. However, due to the typical specification of a garden room they are not suitable for residential use.

On the other hand, a Garden Annexe is specifically designed, specified, manufactured and installed, purely as a permanent living space. Annexes typically include a substantial frame, significant installation and internal fittings that allow individuals to live in comfort permanently within the Annex.

It’s easy to confuse a Garden Annexes with a garden room. When you’re unsure of the details of the specification that’s required for the former and the pricing of the latter is tempting given that a garden room is often less than half the price of a proper garden annex.

To enjoy a permanent comfortable and robust home it is paramount that the materials and the method of construction of the annex is completed without the compromises that are often required by companies that produce a simple garden room.

We always advise our clients to avoid garden room specifications when looking at a permanent home in the garden.

What are the kitchen options in a Garden Annexe?

In addition to manufacturing each element of your annex, we also manufacture and configure our own ranges of kitchens. Each kitchen is designed around the clients’ specific requirements and can be a small or as large as the client requires. We use Bosch appliances throughout the kitchen, and these include oven Combi oven microwave ceramic sink, ceramic hob, extractor fridge freezer, undercounter fridge, under and over cupboards and a selection of pan drawers – all with soft close fittings.

Kitchens can be specified as galley style, L shape, or as a small, separate room.

It’s important that each kitchen is unique to the clients own individual requirements.

How do you configure an annexe?

Each individual annexe we produce is different. The recommended annexe configuration is designed around each individual user’s lifestyle, hobbies and preferences. We’ll also factor in North/South/East/West configuration and the existing garden and household layout to maximise the facility that annexe will bring for all members of the family.

There are unlimited locations for windows, doors, bedrooms, bathrooms, kitchen, lounge and dining areas. Similarly; sockets, light switches and storage are all configured around your requirements and Site Survey stage

Are Garden Annexes delivered in 1 piece?

No.
Each garden annexe is assembled on site in few days from pre-cut components. This means we only require a narrow access to your garden (a typical side passage will be fine)

What does *Turn-Key* mean?

We provide the full service when we install each Annex with our Turn-Key service. This includes a full planning service where we will endeavour to secure an LDC or planning permission on your behalf. Also included in our Turn-key service is the Site pack service and this includes all preparation work including proper concrete base the service trench and the four attendant services:

electrics, water, sewer and Cat6 cable (for phone and internet).

Our finishing service includes completion, connections and commissioning - so there’s nothing the client needs to do within the project at all.

Turn-key means that we undertake every single element until your annexe is completely ready for you to move into.

What maintenance is required for a Garden Annexe?

There’s minimal maintain required for a garden annexe, although we recommend the following good practices.

Each year, make sure the gutters are clear of leaves.

Every 10 years we suggest the annex is recoated with the Owatrol solid colour stain on all external facets. The mono pitched roof is good for a 25-year lifespan, but doublecheck that no overhanging branches or obstructions are damaging the roof. The inherent modularity of the Annex means that should any faults arise then a simple component replacement can be undertaken at any point during the 40-year guide lifespan. Given the materials used and with occasional good practice maintenance, the Annex will remain in good fettle for decades to come beyond the 40-year timescale.

How much does a Garden Annexe cost?

A typical Garden annexe starts at approximately £70,000 for the full turnkey project for a guest suite through to £150,000 for a large two or three bedroomed dual pitched multiroomed Annex.

Our garden annexes can typically be considered to take approximately 20% to 30% less time and expense than alternative annexe options. This is because our unique manufacturing facility and design process eliminates the inefficiencies associated with a typical construction project.

We’re proud of our inexpensive pricing policy (take a look at our detailed price list) and we achieve this through the efficiencies of our modular production, not through compromises with materials or skills.

In some circumstances, however a Garden Annexe may appear to be significantly more expensive than a mere garden room. Whilst it’s easy to be tempted to specify a garden room as full-time living accommodation. But a “garden room” will not be suitable for living space due to the nature of the differences between an annexe and a garden room specification - an annexe being deliberately designed and manufactured and installed to facilitate full time residential use in comfort.

How do I order a Garden Annexe?

After your Site Survey, simply phone us to pay your planning fee by card (or online) and we’ll do the rest !

What’s involved with building a garden annex?

You CHOOSE your style: There’s four beautiful styles. Select from Ivyo, XB, Annexxa or St George

You SELECT your size: There’s 16 sizes, so there’s one to suit you, the garden - and your budget

You CALL us to arrange a free site survey We’ll survey your garden for installation and provide a “one stop shop” price including base, drains etc

We ARRANGE the planning permission / development certificate; you have peace of mind

We PREPARE the base, drains and connections professionally, quickly and efficiently - with minimal disruption

We INSTALL your annexe in just a few days - and then ready for you to enjoy immediately, and for ever.

How can I buy a granny annex?

There are three main ways to buy a granny annex:

1. Commission an architect and select a builder to undertake your project

2. Find a specialist granny annexe company to build a SIPS/modular annexe

3. Specify a Garden Annexe and choose, like buying a car, from the portfolio of pre-designed styles and sizes. This option saves the client signicant amounts of money, time and stress

If you have any question regarding specifying a granny annexe please call Garden Annexes on 0800 368 9781

Can I let my annexe out for air B&B?

Yes, you can let out your granny annex for Airbnb, but only if planning permission is granted. This is because the local authority will consider the use of the Annex as a *material change of use* when it is let out for commercial purposes.

Most local authorities, however, are normally understanding of the situation and if suitable mitigation is put in place to ensure the amenity of the neighbouring gardens are not affected then permission is often granted. This is all part of our planning and certificates and service.

Can I let out my annexe for a lodger?

We have plentiful clients who let out their annex to lodgers in their garden. Planning permission is required in most cases where there is a commercial aspect to the nature of the installation. Our planning service covers applications when permission is required due to the Annex being used by a lodger, however, if the lodger is a close member of the family, then it’s unlikely that planning permission will be required, and a lawful development certificate may be more appropriate in such circumstances.

Is a SIPS based annexe building suitable for an LDC?

A SIPS based granny annex generally is not acceptable to most local authorities for lawful development. This is because this type of construction cannot be considered to enjoy demonstrable movability. Fundamentally, most councils now consider a SIPS based garden annex to be too weak and too structurally insecure to demonstrate significant or realistic movability. Consequently, in most cases, local authorities will strike out an application for lawful development if the structure of the annexe is based on SIPS.

However, unlike a SIPs structure, our unique hybrid garden annexes which can demonstrate an integrated floor assembly and frame structure is recognised to be strong enough to be proven to be completely movable, and therefore an Annex by GX Modular does not require planning permission and a Lawful Development Certificate may be granted, but only as we never use SIPs.

What’s the life span of a Garden Annexe?

Our garden annexes are specified with high quality materials and coatings, combined with detailed and robust construction so that should the Annex go without maintenance at all, the Annexe will have a reasonable life of approximately 40 years. We recommend occasional maintenance in terms of good practice and these actions include a recoating of the exterior, every 10 years and a re-coating of the mono pitched roof every 25 years.

Keep the Annex free from overhanging branches to extend the lifespan of the roof and allow for a re-coat each decade to ensure the 40 year guide timescale. Of course, each annexe is supplied with a full 10-year structural warranty in addition to the standard guarantee provided with all third-party fixtures and fittings.

What are the bathroom options in a Garden Annexe?

We provide many bathroom options for each garden Annex that we supply. The most popular annex bathroom is on BT 21, which offers a full size, shower, WC and basin in a small and compact area with etched window, extractor fan and Pocket door. The advantage of this ensuite bathroom is that it occupies very little footprint of the Annex.

We also specify the BT 22, which is a full 2.1 m x 2.1 m, complete with shower basin and WC and this can be specified as a wet room if required.

Each bathroom is configured to suit the client and the position of the bathroom within the Annex to ensure the optimal ergonomics for comfort.

How many windows are included?

We supply unlimited windows in each Annexe specification to ensure your new home suits you, the garden and your lifestyle.

In many cases, we will make a point of including multiple floor-to-ceiling windows to ensure the Annex lounge is light and bright for a lovely, homely feel. In each bedroom, we will always specify at least one standard opening window as a secondary means of escape just in case. All windows are A rated fully double glazed, and a equipped with key operated window locks, friction stays, trickle vents, and multipoint, locking for safety and security.

How long does the Garden Annexe process take?

Allow 6-7 months from date of order to final handover of keys. The bulk of that time is the 3 month we need to allow for the LDC to be granted by your local authority

We are normally only on site for approximately 4 weeks ( in two lots of two weeks)

How is a Garden Annexe installation project managed ?

You’ll have a dedicated project manager throughout the process – so should you ever need to contact us, you only ever need to make one call. We manage all our logistics and team members from our main office.

What connections are required for my Garden Annexe?

There are four main services provided to your annexe. Two “Dry” services and two “wet services”: all are connected to the main house.

Firstly, we supply and connect a 60a electrical supply from the house to the annexe, and a CAT 6 cable for broadband and landline phone. This is connected to the household router/hub.

From the household water supply we connect a MDPE frost resistant freshwater pipe and connect this to the annexe. We usually connect from the main property’s kitchen and install an additional stopcock. We install the sewer run from the annexe to the house, normally to the manhole adjacent to a kitchen or bathroom. In most cases we install a small pump system which is buried in the ground adjacent to the annexe - this accommodates any rise or fall in gradient the sewer may need.

We place all four services into the service trench that we excavate (and replace all soil and pavia, with minimal impact) and complete the connections prior to handing over your annexe.

Site Pack work is always completed by one of our in-house teams and normally is completed within 5-10 days on site. We supply each client with a fixed price quotation (not an “estimate”) for the completion of all preparation work, so there’s complete peace of mind for you.

Are there second-hand annexes available?

At present, there are no second-hand garden annexes available on the market, but we anticipate that several may become available within the next few years as the user base extends and some families may choose to reconfigure their family lifestyles. Please contact us to enquire about updates.

Do I need to pay Council Tax for my Garden Annexe?

In almost every case, the existing precedent, which was established in 2019, means that a Garden Annexe is not separately rated as long as the annexe is being used by a member of the family that occupies the main house.

What are your payment terms ?

We do not require a deposit or down payment at any point. Payment of our planning fee starts the process, with the 45% required when we start on Site to complete the Site Pack ( groundworks and Services provision). The second 45% is required when we arrive with the annexe, with the final 10% payable when we hand you the keys.

What’s the best size for an annexe?

We recommend a typical interior width 5.5m by 3.9m of interior depth as a starting point for comfortable, full time living space used as an annexe. Smaller spaces make good guest suites.

How long does it take to build a granny annexe?

A bespoke annexe can normally be completed on site within 6 months.

A modular annexe project is often 14-16 weeks on site, our competitors claim

A hybrid Garden Annexe is normally installed in just 5-10 days

How much is a granny annexe?

Bespoke granny annexes normally soak up a budget of £180,000-£250,000 depending upon location and the nature of the construction trade at the time of ordering.

However, most Garden Annexes are approximately £85,000-£100,000 for a turn key package for 1-2 person size.