Why a materials company hands its product to someone else.
The Nigerian Building and Road Research Institute is a federal research institute. It has spent decades on how building materials behave in Nigerian conditions specifically — Nigerian soils, Nigerian humidity, Nigerian rain patterns — and stabilised earth is one of the areas it knows best. It is not a certification body we bought a badge from. It is a laboratory that runs published test methods and reports what the samples do.
That distinction matters more than it sounds. A manufacturer testing its own product chooses the samples, chooses the curing, and chooses which results to mention. Every one of those choices can be made honestly and the result is still unverifiable, because nobody outside the company can check any of it. An independent institute removes the choosing.
So our mixes go to NBRRI, and the programme runs on their methods and their schedule. When certificates come back we publish them here — the numbers, the method used, and the date. Until then, anything we say about performance is an expectation, not a result, and this page will keep saying so.
What is actually being tested.
Four questions, four standard methods. Each one answers something a specifier has to know before they will put a material in a drawing.
Compressive strength, dry and wet — NIS 87:2007
The Nigerian standard for sandcrete blocks, applied here to compressed stabilised laterite. A block is loaded until it fails and the load is recorded against its face area. We run it dry and again after soaking, because the wet figure is the honest one. Earth blocks lose strength when saturated; a supplier who only quotes the dry number is quoting the block on its best day, not the day the rain comes in through an unfinished roof. What a specifier learns: how much load a wall can carry, and how much of that survives getting wet.
Water absorption — BS EN 772-21
A block is dried, weighed, immersed in cold water for a fixed period, and weighed again. The difference, as a percentage of dry mass, is how much water the block will take up. This is not a strength test — it is a durability and detailing test. A high-absorption block is not necessarily a bad block, but it is one that needs a proper roof overhang, a raised plinth and a render, and the specifier needs to know that at design stage rather than after the first wet season.
Wet-dry durability cycling — ASTM D559
Specimens are soaked, oven-dried, brushed, and put through the cycle again, repeatedly. Mass loss over the cycles is measured. This is the closest laboratory analogue to years of Nigerian weather compressed into weeks: the material is asked to swell, shrink, swell and shrink again, and the test finds out whether the stabiliser is holding it together or whether it is quietly eroding. What a specifier learns: whether the wall is still a wall in fifteen years.
Dimensional consistency
Length, width, height and squareness measured across a production run, not on a hand-picked sample. This is the least glamorous test and arguably the one that decides whether the product is useful. A block that varies by a few millimetres forces the mason to correct with mortar, which costs time, costs mortar, and puts a soft joint where the design assumed a hard one. Consistency is what makes an interlocking profile worth having at all.
| Compressive strength, dry | NIS 87:2007 — programme running |
|---|---|
| Compressive strength, saturated | NIS 87:2007 — programme running |
| Water absorption | BS EN 772-21 — programme running |
| Wet-dry durability | ASTM D559 — programme running |
| Dimensional consistency | Production-run sampling — in house, ongoing |
| Cement grade | Grade 42.5R, 50kg bags |
Why we will quote the strength most blocks reach, not the strength one block reached.
Press ten blocks from the same mix on the same day and they will not all fail at the same load. Materials vary. The clay content shifts slightly across a stockpile, the compaction varies a little press to press, the curing corner is warmer on one side. So a test does not give you a number — it gives you a spread.
There are two ways to report that spread. You can quote the best block, which is the most flattering number available and is technically true. Or you can quote the characteristic strength: the value that the large majority of blocks exceed, calculated from the mean and the scatter of the results. Standards are written around the second one for an obvious reason. A wall is not built from your best block. It is built from all of them, and it fails at the weak one.
The practical difference is large. Two products can share an identical best-recorded result and have very different characteristic strengths, because one was consistent and the other was lucky once. A tight spread is worth more to a structural engineer than a high peak, which is also why dimensional consistency and characteristic strength are really the same argument told twice.
This is the discipline the whole company rests on, so it is worth being blunt about the consequence: characteristic strength will always be the lower, less impressive figure. We will publish that one.
What is still open.
The honest list of what we cannot yet tell you, and why.
Third-party carbon verification
We have not commissioned an independently verified life-cycle assessment, so we do not publish a carbon figure. The argument for laterite is structural rather than numerical — less clinker in the mix and a haulage distance measured in kilometres rather than hundreds of kilometres — but an argument is not a measurement. When a verified assessment exists we will publish the number together with its boundary: what was counted, from where to where, and by whom. A carbon claim without that boundary is not a claim, it is decoration.
Long-run exposure data
Laboratory cycling compresses weather into weeks, which is useful and not the same thing as fifteen years of Abuja sun and rain on a real wall. Nobody has fifteen years of data on our material because our material is not fifteen years old. What we can do is start the clock: exposure panels, and monitored early builds we return to and measure rather than photograph.
Structural design guidance
Once characteristic values are certified, the next piece of work is guidance an engineer can design from — wall thicknesses, opening spans, mortar and detailing specifications. That follows the certificates. It cannot precede them.
Specifying with us before the certificates?
Then you should see the current data and its caveats in full, not a summary. Ask and we will send what exists today, including the parts that are still blank.