CONSTRUCTION
SUPERIOR CONSTRUCTION FOR A HAWKSBECK ANNEXE
Working closely with top structural engineers, architects, and industry-leading manufacturers, we’ve developed unrivalled expertise in creating the most exceptional garden annexes. That’s why our annexes are simply the best on the market.
They not only surpass building regulation standards but also offer complete habitability, giving you a comfortable and stylish living space, whether that is for elderly parents or guests and other relatives.
With a remarkable 10-year warranty and a minimum life expectancy of 60 years, you can trust in the durability and longevity of our annexes, making them the perfect investment for your home.
What are building regulations?
Whether you’re planning to use your annexe as an extended living space or for people to sleep in, building regulations are required by law to keep you and your loved ones safe.
All Hawksbeck annexes are built to building regulation standards for peace of mind. Plus, by following these regulations, we help to improve fuel and energy conservation, protect the environment, and promote sustainable development.
The importance of building regulations
We take building regulations seriously to ensure that you and your family’s safety, health, and comfort are always our top priority.
We understand that our clients may want independent inspection for their peace of mind, which is why we coordinate with building inspectors to achieve approval on your behalf. Our annexes exceed the standard regulations for design, construction, and alterations to virtually every building.
Hear From Our Construction Manager, Callum
Structural Strength and Durability
At Hawksbeck, we know that your annexe needs to be built to last, providing you with a durable and reliable space for many years to come.
That’s why all our annexe designs are carefully assessed by our team of experienced architects and structural engineers who prioritise safety, strength, and durability.
We understand the importance of meeting building regulations, and that’s why we include detailed structural drawings and calculations as part of the Building Regulations application.
We want our clients to have peace of mind, knowing that every aspect of their annexe has been signed off and built to the highest standards.
Foundations you can trust
When it comes to the foundations of your annexe, we work closely with building control and our structural engineer to ensure that we install the right foundations for your specific requirements.
Considering factors such as soil conditions, the slope of your garden, and proximity to trees, we design foundations that minimise disruption to your garden and the environment.
Furthermore, our foundations undergo thorough inspection and sign-off by a building control inspector, ensuring their stability and safety.
Vapour control layer
Protecting your annexe from moisture damage is crucial to its long-term structural integrity. That’s why all Hawksbeck annexes feature a vapour control layer in the form of foil-backed plasterboard.
This layer acts as a barrier to reduce the flow of moisture into and through the walls, roof, or floor, preventing damaging condensation that can lead to timber decay.With our vapour control layer, you can be confident that your annexe will remain in top condition for the years ahead.
Breathable membrane
At Hawksbeck Annexes, we understand the importance of maintaining a healthy and moisture-free environment within your annexe. That’s why we incorporate a high-performance breathable membrane that wraps around the exterior Structurally Insulated Panels (SIPs) of your annexe.
This membrane sits behind the external cladding, effectively preventing moisture from entering the main structure while allowing any moisture generated within the annexe to escape. With our breathable membrane system, you can enjoy a comfortable and dry space year-round.
Cladding airflow
Proper airflow is essential for the longevity of your annexe’s timber cladding. That’s why at Hawksbeck Annexes, we use a double battening system for all our cladding, both vertically and horizontally.
This ensures optimal airflow in the cavity, allowing moisture to escape and preventing any potential issues. With our meticulous attention to detail, your annexe will remain in prime condition, free from dampness and decay.
Thermal bridging
Hawksbeck Annexes are constructed using SIPs, which have an insulated core that virtually eliminates thermal bridging.
Unlike traditional timber frame studs, our SIPs provide exceptional thermal efficiency, minimising the transfer of cold spots and preventing dampness.
With our innovative construction methods, you can enjoy a comfortable and energy-efficient annexe, suitable for year-round use and living.
Insulation that keeps you comfortable year-round
At Hawksbeck, we understand that the insulation of your annexe is crucial to its overall comfort and usability, regardless of the weather outside.
Our SIPs, or Structurally Insulated Panels, provide exceptional insulation that outperforms other building methods in thermal and structural categories. This is because the insulation is built into the construction of the annexe, rather than added on afterwards.
Our insulated annexe design achieve exceptional thermal performance and u-values, drastically reducing your heating and energy bills and keeping you warm all year.
This makes a Hawksbeck insulated annexe a truly environmentally friendly option, providing an energy-efficient space for you to enjoy year-round.
Fire Regulations
When it comes to creating an annexe space, fire safety is of utmost importance, especially as they are habitable spaces. That’s why at Hawksbeck, we go above and beyond in ensuring that our annexes meet the highest fire regulations.
According to the regulations, any building located within 1 meter of a boundary needs to be constructed using non-combustible materials. That’s why we use cutting-edge materials like Master board and fireproof plasterboard in all our fire applications.
But fireproofing is not just about using individual elements with Class A1 fire resistance. It’s about creating a comprehensive system within the wall build-up. At Hawksbeck Annexes, we understand this critical aspect.
In addition to Master board and Fireproof plasterboard, we use Structurally Insulated Panels (SIPs) made from OSB3 in our annexe constructions. These SIP’s can achieve an impressive 90-minute fire rating. Combining this with the HBCD in the EPS (Insulation), we take our annexe’s fire rating to well over 4 hours.
FAQs
Do I need planning permission to build a garden annexe?
Yes – unlike our standard garden rooms, most garden annexes require planning permission because they include living accommodation (sleeping, bathing, cooking). They are classified as separate dwellings under planning law, even when built within your own garden.
But don’t worry, Hawksbeck Annexes handles the entire planning process for you, from drawings to submission, ensuring the design meets all local requirements. Our team has an excellent approval rating and years of experience navigating planning policies.
Do I need permitted development rights for a garden annexe?
Permitted Development (PD) typically applies to outbuildings for non-residential use (e.g. a home office or a garden gym). Garden annexes used for living purposes do not qualify under Class E of PD rights – meaning you’ll need full planning permission.
However, we recommend applying for a Certificate of Lawful Use in some cases – for example, if the annexe is used solely as ancillary accommodation for a family member. Hawksbeck will advise on the best route based on your needs.
Do building regulations apply to garden annexes?
Yes, all Hawksbeck annexes must comply with UK Building Regulations, since they are designed for year-round living. We ensure your annexe meets standards for:
- Fire safety
- Structural integrity
- Energy performance
- Drainage and plumbing
- Accessibility (where relevant)
Our garden annexes are inspected and certified by an approved inspector to give you peace of mind.
How close to my boundary can I build a garden annexe?
Under planning rules, you can build close to boundaries, but height and fire safety restrictions will apply.
If your annexe is within 2 metre of a boundary and over 15m², it must be built using non-combustible materials.
The maximum height is usually 2.5m within 2m of the boundary, unless planning permission allows more.
Our expert design team ensures your garden annexe complies with all spatial and safety limits, even in tight spaces.
Are garden annexes allowed in conservation areas or near listed buildings?
Yes, but they are subject to stricter controls:
In conservation areas, your annexe design must respect the character of the surroundings. You may need to avoid timber cladding or modern materials.
For listed buildings, planning permission and potentially Listed Building Consent will be required – even if the annexe is detached.
We specialise in navigating these sensitive applications, offering bespoke annexe designs that comply with all heritage requirements.
What is the typical construction method for a Hawksbeck annexe?
- Exceptional thermal insulation
- Rapid build times
- Superior strength (7x stronger than timber frames)
This ensures your annexe is warm in winter, cool in summer, and energy-efficient all year round.
What types of foundations do you use for annexes?
- Concrete rafts (for maximum durability)
- Ground screws or piles (for sloping or sensitive ground)
Our structural engineers assess your site and specify the safest, most stable solution for your annexe.
How long does it take to build a Hawksbeck annexe?
A standard Hawksbeck garden annexe can be completed in 4–6 weeks after groundwork, depending on size and specification. We provide a clear timeline during your free survey, and our build team works efficiently to minimise disruption.
What materials and finishes are available for my garden annexe?
- Cladding: Cedar, Fraké Noir, composite, or brick
- Roofs: Flat, pitched, gable; EPDM, zinc, slate, or green roof options
- Windows/Doors: Aluminium, uPVC, Crittall-style, bi-folds, French doors
- Flooring: Luxury vinyl, engineered wood, polished concrete, tiles
Every detail is tailored to your taste and the character of your property.
Can I soundproof my garden annexe?
All Hawksbeck annexes offer excellent natural sound insulation due to SIPs construction. For specialist use (e.g. music studios or therapy rooms), we offer enhanced soundproofing options through acoustic consultants.
What is the average cost of a garden annexe?
A fully equipped Hawksbeck annexe starts from £65,000 to £95,000+, depending on size, finishes, and included features like kitchens or bathrooms.
We offer a free site survey and tailored quote with no hidden costs. Every quote clearly itemises:
- Design & planning support
- Construction and groundworks
- Utilities, fittings, finishes
- Project management and aftercare
Does a garden annexe add value to my property?
- Independent space for relatives or guests
- Rental income opportunity (subject to permission)
- Future-proofed home office or accessible accommodation
Do you offer financing for your garden annexes?
While Hawksbeck does not currently offer in-house financing, many clients fund their annexe through:
- Personal savings
- Home improvement loans
- Mortgage extensions or equity release
We’re happy to provide supporting documents to help with any loan or mortgage application.
What warranties do Hawksbeck annexes come with?
- 10-year structural warranty (IWA-backed)
- Manufacturer warranties on windows, doors, roofing
- Optional warranties on flooring and appliances
Your warranty pack is included on completion for total confidence in your investment.
Do you have any other questions?
We’d love to talk. Whether you’re planning a garden annexe for family, work, or rental use, our team is here to help from concept to completion.
For A Free Garden Annexe Site Survey Call Us On 01277 414586
Hawksbeck Annexes
Kings House
101-135 Kings Road
Brentwood
Essex
CM14 4DR