Civil Engineering Reference
In-Depth Information
Chapter 7
CEMENT-FREE FOUNDATIONS
An introduction
the weight of a house. For a small building
constructed of lightweight materials, there is
obviously no need to build massive artificial
foundations on any type of soil. Equally, for
a heavy building built on what we call 'good
bearing soil', there is also no need to use
deep foundations. Almost all the buildings
in the UK and Ireland that are more than
200 years old have natural foundations with
little or no artificial ones. They often use
larger stones at the base of the wall, making
it slightly wider than the wall itself. In all
cases, the builders removed the topsoil and
dug down to something solid, and because
they chose their building sites well, this was
usually just below the topsoil.
Foundation designs for strawbale buildings
have been developed by going back to
basics and thinking through how and why
traditional designs worked. What's great
about this approach is that it keeps things
as simple and cost-effective as possible
AND provides foundation solutions that are
applicable to all buildings, not just straw-
bale ones.
All buildings need to have some sort of
a foundation on which to build. This may
simply be the natural foundation of the
earth beneath, which could be bedrock,
gravelly soil, firm clay, etc., but in today's
world we are more familiar with artificial
foundations such as poured concrete strips
and slabs. As the foundation has to carry the
weight of the walls above it, and other load-
ings such as floors, furniture, roofs and even
snow in winter, it is important to know what
type of earth (or subsoil) is found on your
building site. Different types of earth will
be able to carry different weights. Gravelly
soil, for instance, will carry much greater
weight than soft clay. On the other hand,
if you increase the surface area that bears
the weight on soft clay - much like wearing
snowshoes in the snow - even this can take
Almost all the buildings in the UK and Ireland
that are more than 200 years old have natural
foundations. The builders chose their building
sites well, removed the topsoil and dug down
to something solid.
There are hundreds of thousands of houses
still lived in today that can be excavated
by only 150mm (6“) or so to find they are
sitting on the ground itself, and yet they are
completely sound and safe.
Unfortunately,
