1) Plan access routes to your new extension
Working out the most efficient and practical way to access an extension is often the greatest design challenge. It’s a good idea to avoid access rooms where you can. Weigh up what you’re gaining with the extension and what you’re losing for access – don’t sacrifice more than you’re adding!
Using an existing room to access an extension rarely works unless it is sufficiently large and the furniture carefully arranged. These rooms will often end up as a sort of no-man’s-land for storing odds and ends and won’t end up being useful.
It’s a good idea to have your main rooms, eg kitchen, dining room and living room, coming from the main hallway. In cases of extensions this can often mean a rethink of your room layout. In smaller houses where there is no space for a separate hallway, it is a good idea to have at least a small lobby or enclosed porch to create privacy from the front door.
2) Adding a conservatory? Make it part of your home
Getting the right balance for your conservatory is important. Making it a part of your home rather than just an add on can be tricky. The key is to think about this issue from the first design stages.
Building Regulations require most conservatories to be separated from the existing house by exterior quality doors. (This isn’t always the case and always check your specific situation.) This can leave the new space feeling completely separate and isolated from the rest of the house and unless your conservatory is large enough to be a room in its own right (the minimum is around 3m x 4m) it can end up being an expensive, underused space.
Double doors can be left open to help make a conservatory feel like part of the house, but even double glazed conservatories lose heat quickly and so most people end up closing their conservatory off for the winter months to help keep their home warm and their fuel bills down.
With a bit of redesign to reduce the glazed area, the section of exterior wall separating it from the existing house can be completely removed. This turns the conservatory into a true extension, and by incorporating sections of plastered wall and insulated solid roof, a conservatory can be used to extend an existing room such as a dining room or kitchen.
To turn a conservatory into an extension you must provide your local building control department with calculations that show that the amount of glazing in the windows, doors and roof of the conservatory/extension, together with the amount of glazing in the windows, doors and any rooflights in the original house, do not exceed 25% of the floor area of the conservatory and all floors of the house added together.
New windows and doors in the conservatory/extension will need to meet the current U-values required by the Building Regulations.
3) Don’t forget about your basement!
If you have an existing cellar, you can convert it into living space without using up the volume allocated to you under permitted development rights. Creating basement windows and external access will not usually require planning permission either, although it is always worth checking your local authority’s policy on basements. All work must, however, comply with the Building Regulations laid out in the Approved Document – Basements for Dwellings 2000 Converting existing cellar space to bring it up to habitable standards costs from £1,000-1,500/m² providing there is already enough headroom. Creating a new basement beneath an existing building to add extra space is also possible. The cost is £3,000-4,000/m². Due to the cost, it is usually only financially viable to retrospectively add a basement in high value areas such as Central London.
4) Bathrooms bathrooms bathrooms
Although there are no legal requirements to provide more than one bathroom, it is practical to have a least one full bathroom on the same floor as the main bedrooms. For larger households it helps to have at least one en suite bathroom — ideally to the master bedroom.
If you are extending to add extra bedrooms, clearly creating the number of bedrooms needed for the household is the main priority, but this should, if at all possible, be balanced by an increase in the number of bathrooms. Future buyers will expect at least one bathroom and a shower room on a four or five bedroom house and without this the value will be constrained.
An additional bathroom on the ground floor of a house should be a last resort. It is functional but will add little if anything to the property’s value as bathrooms away from bedrooms are impractical (aside from for those who work outdoors).
5) Don’t get caught out by building regulations
Even if you do not need planning permission for your extension, because you are using permitted development rights, you must get building regulation approval.
The Building Regulations set out minimum requirements for structural integrity, fire safety, energy efficiency, damp proofing, ventilation and other key aspects that ensure a building is safe.
Most repair work is excluded from the Building Regulations, with the exceptions of replacement windows, underpinning and rewiring. However, apart from certain new buildings such as sheds, outbuildings and some conservatories, all new building work, including alterations, must comply with the Building Regulations.
Typical Examples of Work Needing Approval:
- Home extensions such as for a kitchen, bedroom, lounge, etc.
- Loft conversions. Internal structural alterations, such as the removal of a load-bearing wall.
- Installation of baths, showers, WCs which involve new drainage or waste plumbing.
- Installation of new heating appliances.
- New chimneys or flues.
- Altered openings for new windows.