Civil Engineering Reference
In-Depth Information
Chapter 8
Loft Conversions
Chapters 37 of this topic have dealt with the construction of new roofs on dwellings.
There is, however, a growing interest in converting loft spaces to additional accommoda-
tion, this often being the most cost effective 'extension' to the home. This and the follow-
ing chapters give guidance on such conversions from initial survey to construction.
Development of the Loft
Utilising the roof space for living accommodation is not new. Although the very earliest
simple coupled roofs would not have been strong enough to support the floor beneath, by
the fifteenth century the attic had begun to appear. Very early dwellings had no chimneys
as we know them: the additional height afforded by an open lofted room allowed smoke to
rise above the living space to vent through a hole at the ridge.
The combined factors of bricks becoming more available and affordable and the demand
for larger roof spans led to the construction of a centre support which often took the form
of the chimney stack. The large chimney stack was frequently the first part of the house
construction undertaken, this central structural unit later being developed to carry both
floor and roof load.
As houses became larger there tended to be more rooms on the ground floor, and, with
chimneys removing the need for lofty ceilings because of better smoke removal, it seemed
logical to utilise this roof space by constructing a simple floor. This floor was often sup-
ported on the tie beam of the principal truss. These floors were often known as
bastard
roofes
or false roofs; they were later called
ceiled roofs
, hence the word ceiling.
One can now imagine a void above the
bastard roofe
, along the whole length of the house,
interrupted only by the principal truss and possibly the chimney. It was not long before
these voids became used for additional accommodation and the traditional cottage became
a two-storey dwelling. Not all of the house was made two storey; often
