Loft Conversion to a Bungalow
(updated 12 January 2010)
Overview
If you intend to convert an existing loft space
into additional rooms you will need to apply for Building
Regulation Approval. You may also need Planning Permission if you
live in a Conservation Area, Area of Outstanding Natural Beauty or
a Listed Building and/or are installing a dormer window or
rooflight. It is strongly advised that you speak with the Planning
Department before undertaking such work.
This guidance deals with the technical Building
Regulations points, which most often cause difficulties - if you
cannot find ways of dealing with them, it may not be possible to
convert your loft at all.
Latest Building Regulations Requirements
From 6 April 2007 there have been significant
changes to requirements for loft conversions to 2 storey dwellings.
For loft conversions to bungalows, the requirements are less
onerous.
Rooms within the loft should be designed so that
there are no inner rooms i.e. where escape can only be made by
passing through another room, unless the inner room is a dressing
room, a bathroom, a shower room or a w.c.
The new habitable rooms at first floor level
must be provided with escape windows. The provision of compliant
escape windows removes the need to have a protected escape stair to
loft conversions with floors less than 4.5m above ground level.
Escape Windows
Escape windows are to have an unobstructed clear
openable area of at least 0.33 square metres and have no clear
dimension less than 450mm high and 450mm wide (the route through
the window may be at an angle rather than straight through).
Appropriate escape catches and hinges must be fitted to ensure this
clear opening is achieved.
The bottom of the openable area must be a
minimum of 800mm and not more than 1100mm above the finished floor
level. However, for roof windows the minimum height to the openable
area can be reduced to 600mm.
Locks (with or without removable keys) and stays
may be fitted to egress windows, subject to the stay being fitted
with a release catch, which may be child resistant.
Windows (particularly top opening casements and
roof windows) must be designed to remain open without needing to be
held by a person making their escape.
Smoke Detection
Mains powered and rechargeable battery backed up smoke detectors
must be installed on each storey in accordance with BS5839-6: 2004
– Grade D - category LD3 standard.
All detectors must be interlinked together so
that all sound even if only one is triggered and must be placed in
the circulation spaces / protected stairway within 7.5m of every
habitable room door. If, however, due to the layout of the loft
there is no circulation space, a smoke detector should be fitted in
the loft room itself.
Smoke detectors should be mains powered to a
single independent circuit on the dwellings mains consumer unit or
a single regularly used local lighting circuit. A means of
isolating power to the smoke alarms should be provided without
isolating the lighting.
Detectors are to be positioned so that they can
be reached for maintenance and testing (i.e. not over stairs
etc.)
Stairs and Headroom Requirements
A fixed staircase complying with Approved
Document K must be installed to form permanent safe access into the
converted space.
You must have a minimum of 2 metres headroom
over the stairs and landings, although a slightly reduced headroom
standard of 1.9 metres (to centre-line of stair) can be applied to
the stairs where the flight is parallel to the roof slope.
Be aware that the space and headroom currently
available in the roof space will be considerably reduced by the
provision of a new structural floor, the fixed staircase, stair
enclosures or guarding and provision of insulation to walls and
ceilings etc. You should ensure that the finished space and
headroom will make a loft conversion viable before continuing down
the design process.
Modern houses with trussed rafter roofs are
usually unsuitable for loft conversions, as the inner members of
the truss cannot normally be removed. You are advised to seek
advice of a suitably qualified professional to establish whether or
not the roof structure can be altered to accommodate the planned
accommodation.
Other Considerations
The existing ceiling joists in the roof will
almost certainly be inadequate for use as floor joists. In most
cases it is possible to install new floor joists and support beams
between the existing ceiling joists to maximise the headroom
available. You are advised to seek professional guidance and
provide calculations for any support beams you intend to provide to
support the floor.
The new rooms will need to be fully insulated to
prevent excessive heat loss and sound transmission. While there are
many ways of achieving this, we would recommend that you check your
chosen method with your Building Control Surveyor before any
insulation is installed. Be advised that the provision of this
insulation will often reduce the headroom to the existing loft
space.
You should be aware that the above is guidance
only, and there are many other areas where the Building Regulations
impose requirements relating to loft conversions.
You are strongly advised due to the complex
nature of these types of project that you make a Full Plans
application, where the majority of the problems can be resolved
before you start the works.
This webpage was updated on
1/20/2010