Our Garden Building Design Specification

Building Regulations

Building regulations approval isn’t required for garden buildings with floor areas less than 15 square metres. With floor areas between 15 and 30 square metres, building regulations approval isn’t required, provided that the structure isn’t located closer than 1 metre to a boundary line. Both of these regulations apply only if the structure doesn’t contain sleeping accommodation.

Floor

The multi layered structural approach has been developed to exacting standards and provides a base thickness of 180mm – 200mm (150mm Warm Cell insulation and 22mm T&G deck). This meets all requirements with high insular performance (u value) and vapour barrier and breather membrane. The structural ridgidity of the unit is extremely high via the use throughout of 150 mm FSC timber.

Floor coverings include rubber (Dalsouple), solid wood or cork (Forbo)(other traditional coverings are available). The selection of the end solution will again be dependant on the intended use and aesthetic requirement. The key choices all encompass high environmental performance are free from PVC and help achieve a healthy living environment.

Foundations

We have a range of foundation options to suit all eventualities however in most cases our main approach should cope with 80% of all applications. The buildings will be positioned on an augered pile system which is both extremely effective and energy efficient. This is manifest in a 150-200mm diameter hole up to 900mm deep. The hole has a sleeve liner which is then filled with concrete. The size, volume and number required will be ascertained via the site survey. Other foundation solutions can be employed as site conditions may dictate.

Heating and Additional Systems

The buildings can be heated in a number of ways but require little in the way of heating due to the high levels of energy efficiency. The main choices are low energy under floor heating, slim line wall units or a wood burning stove. The larger units can also access solar or geothermal sources of energy and warmth. The lighting systems are energy efficient, flush fitting and low voltage finished in brushed steel by Philips. PV panels and solar water heating can also be specified.

Kitchen and Bathroom

The kitchen specification includes a single bowl sink and double hob, fridge freezer by Philips and with HansGrohe fittings.

The bathroom has Duravit sanitary wear with all fittings by HansGrohe. The wet room is fully tiled and the specification includes a wall mounted toilet and sink. The shower unit has a glass partitian to the main room.

Planning Permission

Granny annexes, or buildings designed to be used as primary dwellings with sleeping accommodation, always need planning permission.

UK regulations that came into force in October 2008, deem that outbuildings do not require planning permission, subject to meeting the following conditions:

- No outbuilding on land forward of a wall forming the principal elevation.
- Outbuildings and garages to be single storey with maximum eaves height of 2.5 metres and maximum overall height of four metres with a dual pitched roof or three metres for any other roof.
- Maximum height 2.5 metres within two metres of a boundary.
- No verandas, balconies or raised platforms.
- No more than half the area of land around the "original house"* would be covered by additions or other buildings.
- In National Parks, the Broads, Areas of Outstanding Natural Beauty and World Heritage Sites the maximum area to be covered by buildings, enclosures, containers and pools more than 20 metres from house to be limited to 10 square metres.
- On designated land** buildings, enclosures, containers and pools at the side of properties will require planning permission.
- Within the curtilage of listed buildings any outbuilding will require planning permission.

*The term "original house" means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date). Although you may not have built an extension to the house, a previous owner may have done so.
**Designated land includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.

Planning Permission & Building Regulations

For garden-based buildings, planning permission is largely focused on the exact location and intended use, as well as the overall size. Planning permission can be an issue with all types of garden buildings, depending on the above factors.

The requirements vary on a case-by-case basis, and it is strongly recommended to consider the particular attributes and location of your building before proceeding. Interpretations of the planning regulations and opinions of deciding officers do vary, depending on the individual qualities of a project.

However, the following information can be used a rule of thumb for the vast majority of garden-based buildings;

Roof

The roof system has also been developed to achieve key requirements with regard to durability, water resistance, insular performance and solidity (u value). The modular and multilayered sectional design is substantial at around 150mm and can be covered in recycled rubber, zinc, lead or even planted green roof system when design allows.

Services

The site survey will reveal what is required and recommendations can be made at this stage. We are happy to look after the installation of all services including; water, drainage and connectivty. Costs for this part of the build process will vary dependant on the distance from the property and proximity of services. The price for this process will be fixed after the site survey.

Survey + Computer Generated Images (CGI)

Once you have selected the unit that you would like from the range we need to give you an accurate quote encompassing all aspects of the project. To enable us to do this we start the process with firstly;

Your initial site survey, this is conducted via a qualified surveyor to ascertain the specific parameters of your site and assess directly a broad range of issues including access, services and sub ground level make up.

Secondly we will develop a computer generated CGI image of your unit and superimpose that within a photograph of the intended site. This serves two purposes, of firstly allowing you to see the specifics of your design (extra windows doors etc…) but also how it integrates into its chosen enviroment. The cost of this service is £900 (inc VAT) and once the main project build is incepted this figure is redeemed against the overall cost of the project.

Walls

The timber structure meets and exceeds modern house build standards. The profile has been is developed to ensure rigidity and reliability. The multilayers in the section gives a thickness of 100mm - 150mm and is based on insular performance and structural requirements. Similarly to the floor section it includes high insular performance and breathability with the advanced heat reflective breather membrane. The wall thickness can be reduced further in the smaller units (yielding greater internal space) with the inclusion high performance rigid insulation. The Western Red cedar cladding is beautiful and has unique colouration and patternation on each section. The cedar is resistant to moisture, decay and insect attack. The FSC certified timber is highly durable and will last up to 40 years without treatment. Coatings (natural oils and paints) can be used to preserve colour and extend life can be applied to the cedar. The internal paint coatings can all be selected from our natural pigment producers such as Farrow and Ball. VOC free and solvent free paint and varnish can also be selected.

Windows and Door systems

All window and door systems are PEFC certified timber window systems. The units are all double glazed, triple sealed laminated frames, and offer ultra low energy loss with 24mm Low E insulating glass. All the window systems are toughened for both security and safety. The trickle vents ensure constant smooth air recycling. All locks and sashes are of insurance standard and well engineered, with key locking as standard. Simulated Divided Light (SDL) designs can be specified if required. The door and window systems are factory fitted with an outward opening casement, with doors available in several folding configurations depending on opening width. Door and window hardware is stainless steel, with optional extras on request.