Stumbelblocks are concrete blocks that were invented to give anyone with limited skills and limited means the opportunity to build their own home in a cost effective way.

The interlocking building blocks are made with the Stumbelbloc plastic moulds, which are simply filled with a concrete mix and left to dry. When removed from the mould, an accurate hollow-core block is created.

They also sell the moulds to make these interlocking blocks so you can start your own business by making and selling them.

Stumbelbloc estimated that the material cost for making a standard block is R4.75 which sells for around R15 for a whole block and R10 for a half block.

The cost of each mould is R204, according to Stumbelbloc an average, unskilled labourer can make up to 50 blocks a day, using the traditional hand-mixing method. With some basic tools and power a small production unit – employing 3 labourers at R150 per day can produce up to 250 blocks per day.

So let’s do the math based on their numbers of 250 blocks per day:
Material cost: R4.75 x 250 = R1187.50
Cost of labour: R150 x 3 = R450 (450 / 250 = R1.80 labour cost per brick)
Manufacturing cost of brick: R4.75 + R1.80 = R6.55
Sales minus cost of sales (R15 – R6.55 = R8.45 profit per brick)
Profit per day: R8.45 x 250 = R2112.50

The above calculation does not account setup cost for moulds and tools and assumes you can sell all your stock for R15 each every day.

Stumbelbloc also has various building plan on their website that you can download for for free. Here is also an excellent article on DIY construction using Stumbelbloc.

Make and Sell Stumbelblocs

Stumbelblocks are concrete blocks that were invented to give anyone with limited skills and limited means the opportunity to build their own home in a cost effective way. The interlocking building blocks are made with the Stumbelbloc plastic moulds, which are simply filled with a concrete mix and left to dry.

All images copyright Stumbelblock


You have a business idea, where to next?
How to Start a Business from Business Idea