Why build with interlocking concrete blocks?
These lego type concrete interlocking blocks allow for a fast construction process. If the project allows for the blocks to be manufactured on site, then transport costs are waived. Typically the shell of a standard house can be completed within a week, ensuring for less construction cost as as result of the reduced labour and time involved.
What is the square metre cost to build with these interlocking concrete blocks?
There is no such thing as a standard building rate per square metre. No two structures are the same and therefore no two building rates are the same. This does not relate to the finishes in a building as finishes on average make up between 20 - 30% of the total building cost.
Cost is always dependent on the specification and the location of the build. Sloping land will increase building cost. The type of soil condition will influence the type of foundations that are required. Naturally, the square metre building cost for a double storey house will also be more than that of a single storied structure.
Take two buildings for example - the one measures 10m x 10mm and the other measures 20m x 5m. They are both 100m² - but clearly the second building is going to cost more. Other influencing factors are going to be the wall height of the structure as well as the window and roof specification. Of course, the other factor is the size of the structure. The bigger the size - the less the cost per square metre.
For the purpose of an estimation, let us assume a level piece of land, a standard foundation and a straight forward roof and window specification, a single storey three bedroomed house measuring 180m² in this situation will cost approximately R3,800 m².
What does this cost include?
Structurally engineered foundation, fully insulated roof, ceilings, cornices, plastered walls, windows, door frames, doors, ironmongery, electrical and plumbing.
What is the thickness of the walls?
Both the external and internal walls are 230mm thick (plastered).
What is the weight of these interlocking blocks?
Each block weighs 16.5 Kgs, which translates into 234 Kg per square metre. This is about 18% less weight than conventional bricks.
Is this method of construction fast?
Building an external wall with bricks only achieves a building rate of 6.16m² (assuming that a bricklayer is able to lay 700 bricks per day). By contrast, 40m² of vertical walling can be completed per day using a crew of three operators - making it 6 times faster!
How do we secure cupboards and shelving onto these wire framed walls?
Shelves, cupboards, TV's and brackets are secured in the normal manner, however special fasteners are used. In cases where exceptionally heavy components are going to be installed, arrangements are made beforehand for the filling of the hollow core of these blocks with concrete in the relative areas.
Can we build a double storey with this method of construction?
What type of windows are used with this method of construction?
Any type of window can be incorporated into wire frame construction. However, considering these blocks are available in incremental measurements of 200mm widths it is important that the windows meet with these measurements. This allows for the pace of construction to proceed unhindered. A full range of polycrete windows are available that suit these interlocking blocks perfectly.
What type of roof can be used for this method of construction?
Any type of roofing material can be secured onto these interlocking concrete block walls.
Is this method of construction approved?
Yes, this method of construction has been approved by the Agrément Board and the NHBRC.
Are there any restriction in terms of design?
No, the boundaries are set by your own imagination.
How long will a house like this last?
There are numerous examples of concrete construction to suggest that structures of this nature should last in excess of 100 years.
What type of foundations are recommended for this building system?
The type of foundation required is determined by the appointed structural engineer - however, a conventional raft foundation would be most suitable.
Will banks provide finance to build these homes?