The main points in brief are:
In 95% of cases. A road facing Dormer needs a planning application. A rear-facing Dormer rarely needs a planning application. A “Velux” conversion never needs a planning application unless you are in a conservation area or your building is listed.
Any project that requires the alteration or installation of drains, foundations, supporting or load bearing members, I.E steel beams, walls, and floors, require building regulations approval by LAW. Regardless of what you call your converted roof space, a habitable room must have the approval of the local checking authority. Failure to do this can result in court action and a maximum fine of £6000. If your property adjoins another, a “Party Wall Agreement” will have to be completed and signed by you and your neighbor(s). Loft Conversion Specialists, provide all the documentation you need to do this.
In homes that already have a ground and first floor, the new second floor must have 30 minutes protection from a fire below it, In most older properties, the first floor ceilings are lath and plaster, or 9mm plasterboard. In these situations, a fire break has to be installed within the new floor section.
The passage-way, from your new bedroom to the front or rear door, is called the “protected shaft”, all doors to habitable rooms, ie: kitchen, lounge, bedrooms, off this shaft, have to be 30 minute fire-resisting, in some circumstances, existing solid doors can be coated with a fire-resisting paint. Another option is the multi smoke alarm system. A mains wired, interlinked smoke alarm with battery back up is fitted in every habitable room and landings. Fire doors need not then be fitted, however, this could mean as many as 12 alarms will go off simultaneously! If you have an open plan ground floor, or a staircase that starts in the lounge or “inner” room you can now install a sprinkler system, either deluge or mist, units are compact and getting cheaper to install.
Staircases must be fixed and rise at an angle not exceeding 42 degrees*, hand-railing and balustrade must enclose the staircase to prevent falling, and no part of that staircase/balustrade must have open spaces that will allow the passage of a 100mm diameter ball. When a new staircase rises above the existing staircase, there has to be a minimum headroom clearance of 2 meters, and please remember, a pull-down ladder does not apply in any shape or form.
* There is a type of staircase called a “space-saver” or “Paddle tread” that rises at 55 degrees, it is legal due to its design, you can see this type of stair by clicking on “Conversion types” then staircase.