Designing Ecological Habitats - Gaia Education

58 Designing ecological Habitats
Market roof in
Villebois-Lavalette,
Charente, France.
which seems to have applied throughout all
time – and more importantly allows two rows of
animals to be tethered within, facing the walls,
while leaving a space to walk down the centre.
The dimension allows for a comfortable space
around a central table and can be divided into two
smaller rooms with ease. In England, France and
northern Italy, such rooms were floored over by a
series of smaller wood beams running fore-andaft,
resting in turn on two major timber beams
running parallel to the façade. The difficulty
of obtaining these latter timbers can be seen in
poorer houses, with timbers often crooked, bent,
tapering or re-used from some earlier structure
often seen. In richer houses, large straight timbers
were ornamented with decorative chamfers and
richly painted decoration. Flooring depends on
the availability of boards. In England, upper floors are usually wide boards,
parged underneath with lime plaster. In France and Italy it was common
to bridge between the wood beams with terra cotta tiles, over which a lime
screed supported tiles, making a very solid and soundproof floor.
9) Shed the Rain and Make a Useable Loft
The roof is a most important element in any traditional building. Keeping
the rain off, and shedding it safely away from the walls, is essential.
The governing principle seems to be to create useable roof spaces while
minimizing both the eaves’ height and the number of junctions in the roof
plane itself. Roofs in most traditions are framed with timber or wood poles,
with a tie beam carefully arranged to minimize the use of heavy timbers.
Thus, simple vernacular buildings are pitched straight off a wall plate using
widely spaced principal rafters and small common rafters supported at their
mid span by underpurlins. In simple buildings, internal walls may well be
called into service to prop sections of roof. Larger and more important
structures are normally trussed across the full span, irrespective of whether
support is available internally. Roof trusses tend not to be fully triangulated,
so as to leave useable space for storage and attic rooms. The roof pitch
is proportioned by simple numerical ratios, or angles constructed using
compasses, never as an angle. 4 More importantly, the pitch in a particular
tradition is derived from the water-tightness of the roofing material in windy
conditions. This is why houses in the Alps, where there is regular snow,
have a low-pitched roof of about 1:4 pitch, while houses in rainy London,
where snow is uncommon, have much steeper pitch. The difference is that
the stone slab roofs used in much of the Alps are relatively waterproof, as
they are constructed with large irregular slabs with many air spaces, while
traditional roofs in London were constructed with small fired clay tiles that