Internal Changes - Building Regulations
Building regulation approval will normally be required for any major internal chances to a house, such as the removal or addition of internal walls. The good news is that planning permission probably won’t be required, unless the building is listed, in which case listed building consent will be needed.
Removing WallsWith the current vogue for open plan living there aren’t many renovations that don't entail the removal of a wall or two but it's important to know what you are doing. It's difficult to give a clear picture of the regulations that might be affected as it depends exactly where the removed wall is and how it relates to the new extension and the rest of the house, but it largely boils down to whether or not the wall is a load-bearing one or not.
If the wall is not load-bearing, that is, it exists purely to separate two areas and doesn't take part in spreading the load of the roof or upper storeys of the house, then it's removal shouldn't cause too much of a problem, but regulation approval will still be required, and it's up to the house owner to get a Building Control Officer or Approved Inspector involved.
Another point where regulations are likely to come to bear is if there are electrical sockets or light fittings on the wall. If that is the case, then the wiring to those fittings will have to be removed and terminated in a way that preserves the integrity of the wiring circuit, and new fittings placed on other walls if necessary. This work is almost certain to require approval but if the person who does the work is properly qualified they can approve it themselves.
With a load-bearing wall a lot more care needs to be taken. It's quite common to take out all or part of a wall to give access to the new part that's being built and obviously if it is load bearing then care needs to be taken to make sure that adequate measures are in place to replace the strength that is lost.
Adding WallsIt is very likely that the addition of any new walls will require approval under Building Regulations. The affected regulations may concern fire safety, sound insulation and ventilation, as well as the placement and opening methods of any doors.
In a domestic context fire safety is unlikely to be an issue, as long as there's a clear path to an exit door that should be ok, but note that the rules will change if the house is to be let out. Apart from that, sound insulation has become an issue in recent years although this will depend on the use that the room is to be put to. Thermal insulation has also had new regulations applied in the past as the government tries to force more energy efficient homes in the wake of the global warming furore.