Building a House
methods and materials
As briefly discussed under the
heading National Building Regulations, a prospective
home owner or designer is actually encouraged
by the Regulations to use innovative designs and
alternative building materials. The promulgation
of this Act therefore saw the spawning of an extended
series of alternative building materials, including
timber products and quite a lot of different pre-fabricated
Since the detailed discussion of all these different
innovative or alternative building methods is
way beyond the scope of this website, inhouseplans.com focuses solely on building plans for houses built
from old fashioned, trusted (and economical) bricks
and mortar. It is however possible to use alternative
building materials (especially timber) for a house,
based on one of the provided building plans.
Site cleaning and
Before any foundation excavations
are undertaken the site must be properly prepared
and cleared by removing all rubble and plant material
like grass and shrubs. If the site is saturated
by ground water, or if the natural flow of rain
water is across the site, a proper drainage system
must be provided to drain the water to the municipal
storm water system. Care is also required not
to generate unnecessary dust and noise pollution.
Anybody building a house is allowed to erect
a temporary builder's shed on the stand, but he/she
is obliged to provide the necessary sanitary facilities
for the workers on the site. One facility per
30 workers must be provided.
Bulk earthworks and
The owner must ensure that all
earthworks and excavations are safe and stable.
All excavations deeper than 3 m must be designed
by a competent person, and must be approval by
the local authority.
All excavations for strip foundations must be
level (horizontal). Where an excavation goes across
a slope in the land, it must be stepped into horizontal
All excavations for strip foundations must be
at least 300 mm deep.
The bricklayer is the person responsible to mark
out on the ground the position of the house, including
all outer and inner walls. This is usually done
by using a tape measure and physically marking
the outer dimensions of the foundations on the
ground using dry cement powder. Since it is much
easier to move a line on the ground than to move
a finished wall, the owner should ensure at this
stage that he/she is satisfied with the position
It might even be advisable at this stage to appoint
a surveyor to confirm that everything has been
set out correctly. This may save enormous cost
later when for instance an encroachment of a building
line has occurred.
On completion of all foundation excavations,
and before any concrete is placed, the building
inspector of the local authority must be called
out for a compulsory foundation inspection. During
this inspection the dimensions and level of the
excavations will be scrutinised, and it will also
be ascertained whether the builder has deviated
from the approved building plan, and whether the
layout is positioned as indicated on the plan.
The foundation of a building must
be designed in such a way that it could easily
transfer the weight of the wall and roof to the
ground. In order to achieve this functional regulation,
the deemed-to-satisfy rules include the following:
Concrete mixed to be poured into the excavation
must produce a strength of at least 10 MPa after
28 days. This is obtained by mixing 1 part cement,
4 parts sand and 5 parts aggregate (usually 19mm
stone). The thickness of the foundation must be
at least 200 mm, and when a step is formed, the
top layer must overlap the bottom layer with 200
mm (the thickness of the layer). The width of
the foundation strip must be at least 600 mm for
load-bearing (usually all outer) walls, and 400
mm for non-load bearing (usually all inner walls).
In the case of non-load bearing inner walls, it
is also permissible to provide a thickening in
the floor slab instead of an own foundation strip.
If this option is preferred, the thickening in
the floor slab should be 200 mm.
In the case of suspect ground conditions, inhouseplans.com strongly recommends that a civil engineer be approached
to recommend a specific design for the foundations.
Building of foundation
A foundation wall is that wall built
on top of the concrete foundation strip, to the
height of the floor slab. All foundation walls must
be 220mm (two bricks) wide. If a foundation wall
is going to be higher than 1,5m, the house should
be stepped to accommodate the slope of the land.
If such a foundation wall is also used as a retaining
wall, it is advisable to build it 330mm (3 bricks)
wide. Foundation walls of higher than 1 m should
be reinforced with brickforce every second layer,
as well as when clay condition occur.
Backfill of foundation
walls and damp proofing
Once the foundation walls have
been built to floor level (also called the "plinth"),
the inside of the house must be filled up (backfilled)
to floor level. It is usually possible to use
the same material that was excavated for the foundation
strips, so always try to leave this material close
by. In order to prevent sagging under the floors,
it is important to compact this backfilled material
to closely resemble the natural density before
excavation. This is easily accomplished by replacing
the filling in layers of 150mm, compacting each
layer properly with a mechanical or hand compactor.
This process will be improved if the layers are
sprayed with water to dampen it. Always take care
however, not to totally soak the material, as
this will wash out all the fine material that
is supposed to fill the smaller openings.
Continue with the backfilling until the final
level is one brick below the final floor level,
which will also be the thickness of the concrete
floor bed. Try to make this top layer as level
as possible. When ground condition are suspect,
it may be advisable to consult a structural engineer,
because a mesh of steel reinforcement may be required.
Pouring of floor slabs
The concrete floor slab must be
75 mm thick (one brick layer) and consist of 10
MPa concrete, mixed from 1 part cement, 4 parts
sand and 5 parts 19 mm aggregate. In areas where
groundwater is a problem, it is advisable to place
a suitable plastic water proofing membrane of
0.25 mm on the filling prior to pouring the concrete.
This membrane must, around the perimeter, be folded
upwards to the thickness of the concrete. An overlap
in the membrane must be at least 150 mm.
It is advisable at this point in time, to consult
with your plumber and electrician to ascertain
whether any services like electrical conduiting
pipes or drainage pipes must be placed in position
before any concrete is poured. This will eliminate
later chiselling and breaking out of the concrete
and disturbing the compacted fill bed..
On completion of the concrete floor
bed, it is time to brick up the walls of the house
to roof height, securing all the door- and window
frames in their places in this process. Always
place steel and timber window - and door frames
on an exact vertical plane, and make sure to provide
horizontal support for door frames to prevent
them from being bended inwards by the pressure
from the surrounding walls. Once again, this is
the last opportunity to make minor alterations,
but remember, only minor alterations. One can
not for instance request a new load bearing wall
if a proper foundation has not been provided for
Remember, aluminium doors and windows are manufactured
and fitted after plastering of the openings, while
timber frames can also be installed after plastering.
If built in like steel frames, proper care should
be taken to prevent the frames from being damaged
during the building work.
Before laying the first brick, a damp proof course
(DPC) should by provided in the form of a continuous
plastic layer the width of the brick wall. DPC
is placed under ALL walls to prevent dampness
from the earth to rise into the walls.
It is always good building practice to brick
up all the walls in the whole building simultaneously.
Many builders are guilty of sloppy building practice
by bricking up one room at a time, leaving "teeth"
in the brick work to tie in the next room's walls.
In areas with a higher rainfall like the Western
Cape, it may be advisable to build a cavity wall
on all outer walls. In a cavity wall, the two
layers of bricks are not built against each other,
but a 40mm gap is left between the two layers.
These two skins of bricks must however be tied
together with evenly spaces wall ties. The gap
between the two skins of bricks then prevents
dampness from outside to penetrate to the inside
of the wall, and also forms an excellent insulator
against temperature extremes.
All window frames and openings for wider types
of doors like sliding doors must be provided with
an reinforced layer over the top of the opening
to carry the weight of the wall above the opening.
This can be done by either using a pre-fabricated
beam called a lintel, or by physically building
a lintel using bricks and a kind of wire reinforcement,
called brickforce. It is also advisable to build
a layer of brickforce into the wall on about every
6th layer of brick work.
All outer (load bearing) walls are built 230
mm wide (2 bricks next to each other), while most
non-load bearing (inner) walls are built 115 mm
wide. If an inner wall is higher that 3,3 m, it
must also be 230 mm wide. Cavity walls are about
280 mm wide.
It is standard building practice to build roof
ties into the top 6 layers of the outer walls.
Either wire or hoop ties can be used, and the
purpose is to tie the roof structure to the walls.
The following deemed-to-satisfy rules should
be remembered considering the layout of the different
rooms of the house:
No habitable room (excluding a kitchen, scullery
and bathroom) shall have an floor area of less
then 6 m², with no linear dimension of less than
2 m. The floor to ceiling height of all habitable
room shall be not less than 2,4 m over a floor
area of 70% of the room. The floor to ceiling
height of all other rooms, including kitchen,
scullery, bathrooms, passage and foyer shall not
be less than 2,1 m.
In order to facilitate natural lighting and ventilation,
all habitable room shall have a window opening
comprising at least 10% of the floor area of that
room, of which at least 50% must be able to open.
It is not necessary to finish off the brickwork
of walls that will be plastered, but all un-plastered
face brick walls must be grooved out properly
between the bricks to have a neat appearance.
Face brick walls must be properly washed as soon
as possible to remove all dirt and cement stains.
Apart from carrying the roof of the house, the
second main purpose of an outer wall is to keep
the inside of the house dry! Always use proper
hard burnt clay bricks ("clincker" bricks
or face bricks) if you don't intend to plaster
the outside of the house. If you intend to plaster
the outside, the layer of plaster together with
the paint layer will keep the water out.
Backfill and water
If the house is built against a slope
that has been excavated and backfill is needed on
the outside of the house against the wall, such
wall must 345 mm (3 bricks) wide. A 0.25 mm thick
plastic sheeting should be built vertically into
the wall to prevent moist from penetrating into
the building. This sheet is built in between the
outer and central layer of bricks. Backfilling is
done in layers of 150 mm and compacted properly.
On completion of all the walls,
the carpenter can put up the roof structure, comprising
either beams for a flat roof, or roof trusses
for a pitched roof. Since the roof is an extremely
important structural element of the house, it
is of cardinal importance that it gets designed
by a competent person. Remember, a roof is subjected
to its own weight, which can be considerable in
the case of a heavy concrete tile roof, and to
wind forces, which can be considerable in the
case of a lighter sheet metal roof. It is therefore
always advisable to have the roof structure properly
designed and constructed. These days it is much
easier and safer to make use of one of many pre-fabricated
roof companies' services. These companies take
the exact measurements, conduct a computer-aided
design, assemble the trusses in the factory, and
erect on site according to specification. This
method is required by most local authorities,
and also favoured by inhouseplans.com,
because an engineering certificate is also issued
on completion of the roof structure. Remember
to look for participating suppliers in the inhouseplans.com on-line business directory.
The minimum slope of a flat sheet metal roof
is 5°, but can go down to 3° if long single span
sheeting are used. The minimum slope of a pitched
concrete tile roof is 26° without waterproofing,
and 17° with an under-tile waterproofing membrane.
During the roof construction, it is the job of
the plumber to fit drainage valleys and flashings
against walls, chimneys and ventilation pipes
going through the roof. Please note that some
local authorities require a roof structure inspection,
as well as an engineering certificate.
After the roof cover has been completed, the
fitting of rain water gutters and down-pipes,
as well as fascia boards are optional.
In the case of a flat reinforced concrete roof,
it must be designed by a structural engineer.
There are various design-and-supply contractors
who will also issue an engineer's certificate
upon completion. Such a contractor actually needs
to be appointed at an early stage, because most
local authorities require an engineer's certificate
before plan approval. All flat concrete roofs
need to be covered with a cement screed, laid
with a fall to outlets, as well as a waterproofing
membrane. This installation must be done by a
specialist who will normally issue a 10 year guarantee.
As always, refer to the inhouseplans.com Business Directory for recommended contractors
in your area.
The owner-builder should take notice of the fact
that on average, once the roof is completed, about
35% of the building costs should be spent.
Plumbing and electrical
Once the walls have been bricked
up, it is time for the plumber to install water
pipes and drainage pipes in the walls and floors
respectively. The underground waste water drainage
pipes should also be installed by now, and inspected
by the local authority. This is called the open
drainage inspection, and is conducted by the building
inspector once the pipes have been installed,
but before they are covered with soil. This job
must be done by a qualified plumber. The complete
water reticulation system is connected to the
municipal water connection point on the stand
boundary. At this stage the owner will be requested
to point out the position of all garden taps.
Since it is difficult to change those positions
later on, due consideration should be given at
Simultaneously the electrician will install conduiting
pipes in the walls and roof structure to accommodate
all the electrical cables for the house's electrical
system. All electrical wiring start off from a
central point, called a distribution box (DB),
which again is connected via an underground cable
to the municipal electrical connection point on
the stand boundary. It is important to choose
the position of the main DB carefully. To keep
costs down, it must be placed close to the main
power connection point, as well as in a practical
position and preferably out of sight, like in
Both the water pipes and electrical conduiting
pipes are installed in the walls by chasing grooves
into the brick walls and mounting the pipes inside
these grooves. Please note that unplastered inner
face brick walls require much more ingenuity from
the bricklayer, because all pipe work must then
be built into the bricks themselves.
Always ensure that the plumber and electrician
are qualified and licensed by their regulating
authorities. If in doubt, just ask for their documentation.
Once the electrician and plumber
have fitted their pipes into the walls, plaster
work can commence. This is a specialised trade
only to be conducted by an accomplished tradesman.
Always take care to use only proper plaster sand.
It should be pointed out here that there are
actually three types of sand used in the building
trade, varying in their degree of fineness: River
sand is the most course, then building sand, while
plaster sand is of the finest quality. With the
necessary experience, a plastering contractor
can achieve various textures in the plasterwork.
Ceilings and Cornice
On completion of the plaster work,
the ceiling contractor can move in to fit the
ceilings. The ceilings are usually suspended from
the roof structure, and be gypsum board, asbestos
boards or even timber. The edges of the ceiling
are usually rounded off against the walls with
some kind of cleat, moulded quarter-round gypsum
board, called cornish.
Please note that it will be much easy for the
plumber to fit the hot water cylinders (geysers)
before the ceilings are installed.
Once the ceilings have been fitted,
the plasterer may move in again to do the finishing
layer on the concrete floor slabs, called the screed.
The screed is thin layer of sand and cement mix,
and is used to make the floor absolutely level.
The floor tiles or carpets will be fitted on top
of the screed at a later stage.
At this stage the building site
really becomes busy as many different tradesmen
hurry around to finish their jobs! The tiler will
now be busy fitting wall - and floor tiles where
specified, the glazers will be installing window
panes, the carpenter will be hanging all the doors
and fitting the locks as wells as the curtain
rails. Once the house can be closed and locked
over night, it is time to install the kitchen
and bedroom cupboards and appliances like the
stove and oven. The electrician will now complete
his job by fitting the wall plugs and light switches,
as well as the light fittings, while the plumber
will be installing the bathroom fittings, baths,
basins, toilets and showers. Various sub-contractors
will complete installations like vanity tops,
stair- and balcony balustrades, alarm systems,
garage doors etc.
After completion, the electrician will issue
a certificate of compliance, while the builder
and plumber will request a final building and
drainage inspection from the local authority.
Once again it is important to note that both the
electrician and plumber are properly licensed
to complete the work. Upon passing a final building
and drainage inspection, the local authority will
issue an Occupation Certificate. This document
is required by law, so never pay your builder
his final payment if he can't hand you the Occupation
Once all the disciplines have moved out of the
house, it is time to install the carpets and skirting
boards and get the painter to finish everything
Before the final inspection, all building
rubble must be cleared up and removed. Then landscaping
and gardening can commence, including paving where
needed, as well as garden and screen walls. Although
gardening and paving can commence earlier, care
should be taken not to jeopardise the house building
Refer to the inhouseplans.com specifications and details on the plans for specific
finishes. The abovementioned information is a
general guideline for a standard house design.
Certain designs of the inhouseplans.com houses have very specific detailing.
It always makes good sense to check references
of all sub-contractors before appointing them.
It also is reassuring to know whether a sub-contractor
is a member of his trade organisation i.e. is
the contractor for the aluminium work a member
Always refer to the Business Directory for a
list of professional bodies.