FAQs

An ISSB is made by compacting a mixture of soil and a stabiliser, usually cement or lime, in a mould that shapes grooves and tongues into the block. Those shapes let the blocks lock together horizontally, vertically or both, so walls can be stacked with much less mortar than conventional masonry.

Soil blocks are pressed and cured, not fired, so no wood or other fuel is burned to make them, and they can be produced right on the building site. Burnt bricks are fired in a kiln, and concrete blocks are made from cement, sand and aggregate rather than soil. UN-Habitat notes that uniform, high-density soil blocks can be stronger than fired blocks and concrete blocks. For a detailed comparison, read soil blocks versus burnt bricks and soil blocks versus quarry stone.

Yes, when they are made and tested properly. Kenya’s State Department for Housing and Urban Development states that ISSB should reach a minimum compressive strength of 2.5 MPa under the KEBS standard, and that strength can be increased where the design needs more load capacity. It also says the blocks can be used for buildings of up to three storeys when guided by a qualified structural engineer, or as infill in framed structures. Always have the structure designed by an engineer, and test blocks from your own production.

According to the same government source, KEBS developed a standard for stabilised soil blocks in 1993, referred to as KS 02-1070. Standards are revised from time to time, so check with KEBS for the current version before you start.

Use fine-quality subsoil that is free of organic matter and does not contain harmful amounts of salts. Soils with a lot of clay tend to crack as the blocks dry. If you must use them, blend in sand or quarry dust and use more cement. Black cotton soil is generally not suitable. UN-Habitat adds that lime can work for high-clay soils but takes longer to harden. Our soil testing guide shows three simple field tests.

There is no single answer, because it depends on your soil. Makiga explains that the soil has to be stabilised with cement according to how much it shrinks. As an example of a typical mix, UN-Habitat’s technical note describes a composition of about 60 to 70 percent soil, 20 to 30 percent coarse sand and 8 to 10 percent cement. Treat that as a starting point, make trial blocks and test them. See choosing the right cement ratio.

The mix should be moist but not wet. A simple check from UN-Habitat is to squeeze a handful: no water should run between your fingers. Use clean water, and add it gradually after the soil and cement are mixed dry until the colour is uniform.

Curing starts on the second day. Cover the blocks with grass or plastic sheeting and water them every morning and evening for at least seven days, and more often in hot weather. Full curing takes about 28 days. Kenya’s housing department says construction can begin after 21 days, while cement reaches full strength at 28 days. Read our guide to curing stabilised soil blocks.

The Kenyan government’s guidance gives roughly 37 blocks per square metre of wall. The exact number depends on the block size and the wall design. Our costing worksheet shows how to work out your own figure.

Not always. The blocks are uniform and have a neat face-brick appearance, so many builders leave them unplastered, which also saves money. Whether you plaster depends on the design and how exposed the wall is. Whatever you choose, protect the walls with a generous roof overhang, a raised plinth and good drainage. See finishing options and protecting earth block walls from rain.

UN-Habitat points out that the density and thermal properties of soil blocks let walls absorb heat during the day and release it at night. In practice that helps keep the inside cooler by day and warmer at night. Design details such as shading, ventilation and roof type also matter.

They can. Because the blocks interlock, much less mortar is needed. Making them on site removes transport costs, plaster can often be avoided, and walls go up quickly because the blocks are stacked. The actual saving depends on local prices for soil, cement, labour and competing materials, so compare using your own numbers.

The main challenge is finding suitable soil. Block quality also depends on the raw materials, how well they are mixed, and the moisture content of the mix. A common mistake, according to the Kenyan government’s guidance, is failing to test the compressive strength of blocks as quality control. Read common soil block making mistakes for a checklist.

Our interlocking presses include the Standard Straight, the Curved, the Wide and the Medium machine. We also make a standard non-interlocking machine, described in this article. Browse them all in our shop.

According to the product page, it is a heavy-duty, manually operated, low-maintenance machine that weighs 140 kg, needs three to four people to operate, and makes 400 to 500 blocks a day. The blocks measure about 10 x 6 x 4 inches (length x width x height). The machine has to be mounted so that it spreads the force needed to press blocks. The main materials are soil, cement and water.

No. The Makiga interlocking presses are manually operated, so you can produce blocks wherever you have soil, cement and water.

The Standard Straight listing says the purchase includes the complete interlocking soil block press set, a free soil testing kit, free training and documentation for your staff, and free delivery to all major cities in Kenya. Charges may apply for delivery outside Kenya. Offers can change, so confirm the current terms when you order.

The Curved Interlocking Soil Block Press makes curved blocks that can be used to build water tanks and round houses. A water tank in particular must be designed by an engineer. Read more in curved interlocking blocks: round houses and water tanks.

Makiga Engineering Services has a head office in Nairobi, Kenya, and branches in Uganda, Tanzania and Rwanda. Contact details for each location are on our Contact page.

Prices are listed on each product page, and you can order online or through the WhatsApp button on the page. You can also contact us or email admin@hustlepilot.co.ke to discuss quantities, delivery or training.

Clean the mould after every shift, lubricate moving parts, keep the fixings tight and store the press under cover. Our maintenance routine explains what to do daily, weekly and monthly.

The Block Master is a Makiga machine for making solid concrete blocks. Makiga’s article on Blockmasters describes two sizes, an 18 inch and a 16 inch model. See the Block Master product page for the current options and price, and our article Blockmasters for Solid Concrete for background.

Dimensions below are length x width x height in inches, as listed in our Blockmaster article.

• Blockmaster 18″: 2 blocks of 18 x 9 x 8, or 3 blocks of 18 x 6 x 8, or 4 blocks of 18 x 4.5 x 8.
• Blockmaster 16″: 2 blocks of 16 x 8 x 8, or 2 blocks of 16 x 6 x 8 plus 1 block of 16 x 4 x 8, or 4 blocks of 16 x 4 x 8.

Confirm the configurations available on the product page when you order.

No. The Block Master is described as a solid concrete block machine. For interlocking stabilised soil blocks, use one of the interlocking soil block presses listed above.

Concrete blocks are made from cement, clean sand, aggregate (or quarry dust where appropriate) and water, mixed to a stiff mix and cured while damp for several days. The right proportions depend on the strength you need and the quality of your materials, so ask your supplier or an engineer for a starting mix and test your blocks. Read understanding crushed stone sizes and how to make cabro paving blocks for related guidance on aggregates, mixing and curing.

It depends on the material and wall type you want. A soil block press makes interlocking blocks from local soil and a small amount of cement, while the Block Master produces solid concrete blocks. Compare both on cost per square metre of finished wall, using the method in our costing worksheet, and think about the materials available near your site. Our article on concrete block house construction in Kenya is also useful.

The product page shows a price range because the machine is offered with different options. Check the Block Master page for the current price.

Yes. Our range also includes the I Shape Paving Block Press, the Charcoal Briquette Press Machine, a 7 to 30 ton per hour diesel stone crusher, a multi-purpose vibrating table and a range of moulds.