There
are a variety of concrete mixes shown in the Detailed Construction
Guide that comes with the machines which may be used for different
applications and depending on the materials available in your
immediate area.
The most common used 15 to 20 MPa mix is:
| 2
x |
Building
sand |
(2
wheelbarrows) |
| 1
x |
Cement
(2 pockets of 32.5) |
(2
pockets of cement) |
| 30ltr
x |
Water |
(30
liters of water) |
CONCRETE
STRENGTHS
Recommended
mixes detailed in the Construction Guide are:
| Perimeter
wall under 1.8m high, shed, bird or small animal enclosure |
5
- 10 MPa |
| Perimeter
wall over 1.8m high |
0
- 15 MPa |
| Single
and double storey houses (depending on the wind loading) |
15
- 20 MPa |
| Reservoirs
and large animal enclosures |
20
- 25 MPa |
| Retaining
walls |
25
- 30 MPa |
MATERIAL
USAGE
One
of the biggest attractions of using FinnBUILDER™ is that
it is a lot less expensive than building with brick or blocks.
See Cost Comparisons for further detail on this. You can
calculate the amount of material that you need to use following
this simple guide:
| 1. |
Decide
whether your walls will be 220 mm thick, 150 mm thick
or 110 mm thick. |
| 2. |
From
your plans, measure the length of you walls and the
height. |
| |
Calculate
the area of your walls by multiplying the length by
the height. e.g. if the wall is 50 meters long and 2
meters high, the area of the wall is 100 m2. A cement
pocket weights 50kgs and costs about R 70.00 each |
Calculate
quantities required and cost based on wall of 100m2
|
Tickness
of wall
|
Aggregate
needed / m2
|
Cement
needed / m2
|
Total
aggregate needed
|
Total
cement needed
|
Cost
of aggregate @ R150 / m3
|
Cost
of cement @ R70 / pkt.
|
|
220mm
|
0.253m3
|
43kg
|
=
25.3m3
|
=
86 pkts
|
=
R 3 795
|
=
R 6 020
|
|
150mm
|
0.13m3
|
29kg
|
=
17.3m3
|
=
58 pkts
|
=
R 2 595
|
=
R 4 060
|
|
110mm
|
0.127m3
|
21kg
|
=
12.7m3
|
=
42 pkts
|
=
R 1 905
|
=
R 2 940
|
Total
aggregate needed will be divided up on the ratio of the
mix that you have elected to use as per the Detailed Construction
Guide.
DOUBLE
STOREY HOMES
Since
1946 double storey homes have been built using FinnBUILDER.
Examples are shown in the Gallery.
FOUNDATIONS
The
plans for your house or structure must be drawn by a qualified
architect or architectural designer, who will need a Civil
Engineer to specify the type and thickness of the foundations
that you need to pour, given your soil conditions and the
loadings that your structure will carry. Generally foundation
trenches will be a minimum of 600mm deep below natural ground
level (NGL), and 650mm wide for external walls and 450mm
wide for internal walls.
Foundations
are a critical part of any building. If you are not a civil
engineer, make sure that you have dug your foundation trenches
down to firm footing throughout the trenches, and then call
in the Municipal Inspector and the professional engineer
to inspect your foundation trenches and approve them before
you throw your concrete.
Once
your foundation trenches have been approved, use a foundation
concrete mix of 3 wheelbarrows 19mm concrete stone, 3 wheelbarrows
of river sand and 2 pockets of cement plus 80 liters of
water to throw your foundations 200mm thick. Double storey
foundations will vary in depth.
Retaining
walls can be inexpensively built using the system. Once
again the design of the wall is a technical issue which
must be properly addressed by a professional engineer. Vertical
steel running out of the foundations and into the wall,
structural piers and adequate drainage ports are some of
the design elements which needs to be considered.
SABS
TESTING
SABS
testing has taken place on our concrete mixes to confirm
that they achieve the required strength.
NHBRC
The
NHBRC is now the watchdog of the building industry and under
new legislation during the last fifteen years, new building
projects have to be approved and enrolled with the council
before bank financing can be granted.
The
NHBRC has approved our FinnBUILDER RATIONAL DESIGN and will
enroll sites that will be building using the system. The
requirements of the NHBRC include the appointment of a Competent
Person to monitor construction with the QUALITY MANAGEMENT
SYSTEM and who will be responsible for signing off that
the building has been built in accordance with the RATIONAL
DESIGN.
MUNICIPAL
REQUIREMENTS
Once
the requirements of the NHBRC have been met, Municipalities
in South Africa will accept your plans. If they have further
questions, you are welcome to refer them to ourselves so
that we can answer any further technical questions that
they may have.
The
plans that you submit to the Municipality to specify that
you will be building with "slip form concrete shuttering,
using 15MPa no-slump concrete".
AGREMENT
CERTIFICATION
Now
that we have full NHBRC Accreditation, it is no longer necessary
for us to persue Agrement Certification. The system already
enjoys acceptance throughout Africa and many other countries
in the world. For this reason we are no longer persuing
Agrement Certification.
|