The method of building is 10 times faster than normal. A standard structure can be built to roof height in one day. No time is wasted on setting up profiles and preparing mortar mixes. The labourer carrying the block actually lays it instead of handing it to the artisan. No time is spent cleaning up afterwards. If required, several labourers can work at the same time without interrupting each other’s work.
Much less material is used than in conventional building and the labour cost is a fraction of the normal rate because unskilled labour can be used to do the work of otherwise expensive artisans. For standard openings (windows/doors) Stumbelbloc may be used in place of lintels – saving time, money and procurement/delivery costs. Finally, the use of Stumbelbloc eliminates almost all building waste. Any surplus standard mortar can be used to make more blocks.
Yes, any sort of concrete or plaster sand may be used but the finer the sand the weaker the finished block will be. Sand containing any organic material or salt should not be used. River sand is preferred. Sand with best properties comprise of particulars that has a variation of fine to coarse sand grains and must have no clay form.
The blocks can be made with any material that can bond with cement. As stated previous, the strength of the finished block will depend on the material used. For example, volcanic sand/any crushed rock material is ideal when mixed with cement. Please note: ORGANIC material is not suitable for making the blocks and should not be used.
The strength of the finished block is determined by the mixture. The recommended mix is 2 level wheelbarrows of sand, 1 x 50kg bag of 42 MPa cement and 2 level wheelbarrows of chipped stone (Not larger than 13mm stone), gives a block of roughly 5,2 MPa strength. The required strength in most countries for a concrete block (Reference B-Block) is 3,5 MPa. The block can be strengthened to any level by simply adding more cement. The above mixture makes 28 large blocks.