Conservatory

A conservatory is not classified as a ‘habitable room’ if the following criteria are met and therefore does not have to satisfy building regs or be certified by a Building Control Officer:

• At least 75% of the roof is made of transparent or translucent material.
• At least 50% of the walls are made of transparent or translucent material.
• The conservatory has a floor area not exceeding 30m2 (323 sqft).
• The conservatory is a single storey sited at ground level.
• The conservatory is permanently separated from the rest of the building by a door.
• Any radiators within the conservatory are independently controllable from the rest of the system.
• The conservatory does not contain any drainage facilities for a sink, wc or washing machine.
• The glazing satisfies requirements of building regulations part N, summarised here.

• Indeed, due to its resistance to breakage, it is sensible to include laminated glass throughout the construction of a conservatory for improved security.

Where each and every of these criteria are NOT met, the conservatory technically becomes an ‘extension’ which is subject to building regs and must be signed off by a Building Control Officer.

As is fashionable these days, a conservatory added to extend a kitchen generally has no door or partition, and is therefore falls into this category.

In particular, the following regulations become pertinent:

• Foundation design is adequate.
• Damp prevention through the use of damp-proof courses in the walls and a damp-proof membrane on the floor.
• Drainage ensures that rainwater from gutters and downpipes is safely delivered to a suitable drain, not just a water butt.
• Ventilation of adjacent rooms is maintained.
• The walls (both brick and glass) are suitably insulated against heat loss, so all new glazing in the extension must have a U-value of 2.0 or less AND the total area of glazing in doors, windows and roof of the whole house, including the new extension, does not exceed 25% of the total floor area of the whole house including the new extension.
• Integrity of fire detection, resistance to spread and escape is maintained.

• Guide to cavity wall insulation

Loft Conversion

All loft conversions will have to meet the latest building regulations and be certified by the local Building Control Officer. This is because the loft is being turned into ‘habitable space’ which must therefore have suitable levels of health and safety. With this in mind, the following areas are particularly important:

• Structural strength of the current top floor must be sufficient to support another habitable level. This will usually require at least two new RSJs (rolled steel joists) to be inserted into the walls of the top floor. In addition, the existing joists in the roof void are likely to measure 102mm x 51mm (4in x 2in) which will not support a new floor. New fire-resistant joists measuring at least 153mm x 51mm (6in x 2in) will have to be installed.
• Your loft conversion will more than likely turn your home into a building with three or more stories, in which case certified fire doors, with self-closing mechanisms, will need to be fitted to staircases, escape routes and communal areas.
• A fire exit must be provided from the roof. This will most often be in the form of a window, glazed with safety glass and with a minimum openable area of 0.33m2 (3½ sqft).
• Adequate ventilation must be provided to loft room by means of one or more windows, which must be glazed with double-glazing that has a U-value of 2.0 or less.
• The loft walls and ceiling must be suitably insulated to be energy efficient.
• All electrics and plumbing must be safely installed.

• Fire doors
• Window requirements of the building regulations

If your home is terraced or semi-detached, the additional RSJs required to support the new loft room will invoke the Party Wall Act 1996, and you should be sure to gain written consent from your adjoining neighbours for work to proceed.

Basement

All basement developments will be subject to building regulations and will need to be certified by a Building Control Officer. Regulations applying to ventilation, damp-proofing, fire escape, energy efficiency, electrics and water supplies will be given particular attention.

• Foundations need to be adequate to support the structure of the whole house, including the new basement.
• Occupants of the basement must be able to escape from a fire by means of an independent staircase or fire egress window.
• The walls of the basement must be suitably damp-proofed.
• Adequate ventilation must be provided to the basement by means of an open staircase, a window or airpipes, especially if the basement houses a bathroom, bedroom or kitchen.
• All new glazing in the extension must have a U-value of 2.0 or less.

To overcome any concerns of subsidence, if your home is terraced or semi-detached or the excavating of a basement will in anyway approach a neighbour’s boundary, you will invoke the Party Wall Act 1996, and you should be sure to gain written consent from your adjoining neighbours for work to proceed.

Further information and useful links

• Regulations & permissions for extensions
• Full guide to the building regulations
• Introduction to extensions

• Find an Architect near you
• Find a Chartered Surveyor near you
• Find a Builder near you

• Full building regulations documents (planningportal.gov.uk)