In a low rise residential building everything under the damp
proof course is the substructure this would consist of the ground floor and the
foundations and this is where I’m going to be starting.
The main origin of any building would be the foundations; these
would be the base on which a building would be built upon. Its main function
being to provide a firm platform for a building to be erected upon, while also
supporting the surrounding soil from the load of the superstructure. This is
done by evenly distributing the weight over a larger surface area so that the
load bearing capacity of the soil isn’t breached and therefore preventing
warping of the soil when there’s a building constructed overhead. If the soil
load bearing capacity is breached there is a possibility of the foundations
moving which would cause distortion of the assembly.
To make the foundations as stable as possible you must take
into consideration the soil type, as water uptake can cause foundations to
alter. Clay is a constantly changing soil depending on the availability of
water and then the weather on the soil would also have effect; at cold
temperatures there would be a freeze thawing process taking place causing
movement of the soil.
You’d also need to take into consideration the particle sizes of the soil and
the interactions between stratums as you wouldn’t want the layers to be
slipping apart from one another while digging out trenches this is when pile
foundations are required.
Concrete is necessary in construction, but it isn’t the only
option as there is always the cheaper option of wood. Traditionally concrete
was used on its own as it was a pliable material that starts off liquid and
easy to mould into any shape and crevice but over time due to technical
development the use of reinforced concrete is the way forward as the wider
strips of foundation aren’t compromised when the load of the building causes
the strip to bend and inevitably snap which would be going against the purpose
of it. Concrete blocks are made beforehand they are used rather than bricks as
they speed up the bricklaying time and they help form a layer around the
concrete, so it isn’t affected by the surrounding soil. For smaller buildings
the cheaper option would be to use treated wood that is waterproofed and
prevents rotting due to chemicals and that resists pressure changes.
The purpose of floors is for a flat surface on which the
occupant of the building can place their possessions and can safely operate
Ground floors can be divided into 2 elementary categories
they’re either solid ground floor or they’re suspended floors. The type that is
chosen depends on the requirements of the building.
The ground floor must be able to withstand the live and dead
weight of the building, solid ground supports would be in constant contact with
the ground and therefore it’d be evenly distributing the weight across the
area. There is the possibility of induced tensile stress on suspended ground
floors as they would need to transfer their load to the foundations for support
with the use of sleeper walls. The sleeper walls also keep air flowing so the
moisture levels aren’t exceeded and therefore preventing the rotting and
decaying of the timber used as joists to hold the floor.
The benefits of having a solid ground floor is that there is
less heat loss due to the centre of the flooring having a steady state where
heat loss is at a minimum and the greatest is at the outermost edges where heat
is lost to the surroundings, with the addition of insulation you could reduce
the loss. The same can’t be said for the suspended ground floor as you would
need to insulate the whole floor area as the void created would mean there’s a
greater heat loss, therefore a higher cost on insulation.
Solid ground floors are made using concrete and if they are
required to due to a heaving mass load they would be reinforced with steel
bars, it will then have Damp proof membrane laid down all the way to the DPC in
the walls, so it becomes a continuous barrier against water. Above this you
would finally add either sand or cement screed, so it has a finished layer.
Then the client may add whatever kind of flooring they wish, whether it be
tiles or wood.
Suspended ground floors were traditionally made using wooden
beams but with development there is now also the use of precast concrete beams
that are held in place by concrete blocks. For the wooden beams they would be
suspended on sleeper walls that would be supported by concrete flooring
(oversites) and then plastic mesh is inserted in-between the gaps where there
is installation of insulation to keep it in place. The concrete beams are
inverted T shaped precast beams that are there to support the concrete slabs
that are inserted in-between them; so, they’re not in contact with the floor.
This is then layered with cement grout for a more uniform finish. This is ideal
for homes that are built on slopes or don’t have ideal conditions for the
oversite to be laid and the beams to rest on like those for timber, this is
also the more cheaper and quicker option.
Next, we have the superstructure that rests upon the
substructure this is 150mm, all buildings have walls these are either load
bearing walls or non-load bearing.
In modern construction external walls are loadbearing walls, there are key
requirements that these walls must attain for them to be suitable:
and Strength: They must be strong enough to not collapse under pressure of
the load they’re bearing; including that of the roof or any other additional
factor such as wind load or earthquakes that would increase lateral
pressure and could cause parts of the building such as the roof to lift.
They must provide not only heat insulation but also sound insulation.
resistant: To protect habitants from the external changes while
maintaining an internal environment of their desire.
resistant: They must be a barrier that will withstand for a set amount of
time without giving way and preventing the further spreading of fire and protecting
the residents of the building.
It must be a closed off as its someone’s private property where they would
need to feel a sense of safety and security without any trespassers
The External walls must be visually pleasing for passers-by, taking into
consideration what the clients requirements.
These types of walls are masonry walls consisting of the use
of either clay bricks or concrete blocks and these are then bonded to one
another with the use of cement mortar which once cured has the same load
bearing ability of the bricks. The only disadvantage of masonry walls is that
they’re porous and therefore absorb water, however the water absorb is
erratically being dried up by the wind. However, water is still in the middle
of these bricks to prevent the moisture from entering the building precautions
can be taken such as weatherproof cladding on the exterior of the building
which would form a barrier between the wall and the external environment. For
the cladding you could use aluminium sheets or panels of plastic or glass, but
these are unsightly and therefore not used on low rise residential buildings
instead they use damp proof coursing in the cavity of the external walls which
helps to keep all moisture out as it forms a barrier and the capillary action
of the water can’t continue any further. In the cavity wall there is insulation
that traps the heat and prevents it from being wasted by being lost to the
surroundings and it can also act as a barrier to keep water out, the partial
fill insulation is a board of insulation that is adhered to the surface of the
inner leaf or you could have full fill insulation which would be mineral wool
that would take up the entirety of the cavity space and would be the better
option for insulation.