Moladi Affordable Housing Africa - Conventional brick and mortar building methods not suited to African conditions - plastic formwork Reduced cost

1. 48 ENGINEERING NEWS | May 20–26, 2016 RA
H
ousing and construction systems
developerMoladisaysitslow-costhous-
ingsystem,comprisingplasticformwork
panels and a cement admixture, is widely
embraced throughout Africa, as it has been
specifically designed to meet the requirements
of the African market.
Moladi founder and CEO Hennie Botes says
the system alleviates challenges associated
with conventional building methods, including
excessive costs, labour-intensive processes and
theavailabilityofmaterials.Henotesthat,while
the aforementioned challenges are not specific
to African countries, they are exacerbated by
other uniquely African obstacles.
Botes adds that the Moladi system works
because it circumvents the lack of adequate
infrastructureandfunding,aswellasthedearth
of skilled labour prevalent in sub-Saharan
Africa. “The system can be easily transported
to virtually anywhere, including far-flung rural
areasandinformalsettlements.Theconstruction
processdoesnotrequireskilledlabourers,heavy
machinery or electricity, and the system uses
building materials that are locally sourced.”
Further, a structure built using the Moladi
system costs about 30% less to construct than
a similar structure that uses conventional
methods.
The system uses lightweight, reusable form-
work to create a mould filled with aerated
mortar – which has been approved by national
standards authority South African Bureau of
Standards and certified by national assessment
body for nonstandardised construction
materialsAgrementSouthAfrica–toformwalls.
Typically, a cubic metre of Moladi’s mortar
comprises 1 800 kg of local river sand, 250
kg of 42.5 N ordinary Portland cement, 5 ℓ of
MoladiCHEM(anontoxicwater-basedchemical
mixture) and 200 ℓ of water. Botes states that
admixture produces a mortar that “flows easily,
is waterproof and has good thermal and sound-
insulating properties”.
He says before the start of each project, the
locally acquired aggregate undergoes testing
at Moladi’s laboratory in Johannesburg. “This
is to ensure that the aggregate is the correct
size and quality for structural stability, and to
determine the correct ratios of cement, sand,
waterandMoladiCHEMtoproducethedesired
compressive strength.”
Botes mentions that the number of workers
requireddependsonthesizeofthehousingpro-
ject, but that between four and ten workers are
typically required to construct a 45 m2
hous-
ing unit. Unskilled workers from the area can
be trained on site by a Moladi foreman over a
two-week period. The process of erecting the
firsthouseformspartofthetrainingprogramme.
While there is no additional cost for training,
arrangements for the foreman’s travel, food and
accommodation have to be made and/or paid
for by the client.
The client, whether a rural community, local
contractor or nonprofit organisation (NPO),
is supplied with a working document and
assembly instructions, including the guidelines
and recommended mix design for the mortar.
Botes says “it is essentially up to the client to
ensure adherence to our guidelines. However,
asaqualityassurancemeasure,Moladirequires
consistent strength testing of the mortar mixes
from an independent laboratory”. Moreover, a
certified structural engineer has to approve the
design, reinforcing schedule and housing units
before they can be occupied.
Construction Process
Botesexplainsthatthehousingunitsareerected
on a floating raft foundation. The formwork
panels comprise interlocking components that
join to form wall configurations of any length or
height, but with a thickness of 150 mm for
externalwallsand100mmforinternal,nonload-
bearing walls.
The internal panels are erected first, with the
steel reinforcing, window and door block-outs
positioned within the wall cavity. The external
panelsarethenerectedtosealoffthewallcavity
prior to it being filled with the mortar mix. For
a relatively small structure (between 45 m2
and
74m2
),thisphasetakesafour-personteamabout
six hours to complete.
The mortar sets overnight or after 12 hours
in good conditions. “The setting time will not
be affected if the temperature remains at 20 °C.
Should the temperature be cooler than 20 °C,
the mortar would take proportionally longer to
set. Significantly, the effects of rain are allayed
as the mortar is securely placed and covered by
theformworklimitinganyunwantedexposure.”
Once the mortar has set, the panels are
removed, and the various sections can be
transferred and reused for another housing
unit on the same site. The first unit’s walls are
painted using cementitious water-based paint;
the roof, windows, doors and finishings, such as
lighting and sanitary ware, are installed. This
phase takes about ten hours.
The system is ideally suited to large-scale,
low-cost housing projects. Botes says Moladi
has not participated in the Reconstruction
and Development Programme housing project
because “it is a question of finding the right,
reputable contractor and developer to work
with”. He believes that finding a reliable partner
will ensure that Moladi is not associated with
any of the negativity that the programme has
been associated with, specifically, reports of
substandard houses.
The company has, however, been involved in
numerous projects with NPOs and nongovern-
mental organisations for similar community-
based low-income housing initiatives.
Conventional building
methods not suited to
African conditions
CONSTRUCTION
FILING THE GAP
Aerated mortar is used to fill Moladi’s formwork
mould in order to create walls
QUICK AND EASY
The alternative building system reduces costs
and labour-intensive processes
NADINE JAMES | CREAMER MEDIA REPORTER
When one has a good table, he is always right.
– French
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