Made in the UK from 100% recycled polypropylene
Made in the UK from 100% recycled polypropylene
Technical articles and project lessons will be published here.
What this is
The Insights section collects the practical explanations that do not fit neatly on a product or application page: why a gravel surface ruts even when the grid is correct, how drainage design decides whether a permeable surface actually performs, which gravel grades behave on a slope, and which of the common installation shortcuts cause the failures we see most. Each piece is written from documented cases and published guidance rather than general opinion.
The aim is to be genuinely useful to the person holding the shovel as well as the person writing the specification. That means plain explanations of the mechanism first, then the numbers, then the limits — the same order every other page on this site follows. Where a topic is contested, the disagreement is set out rather than smoothed over, because a reader who understands why two guides differ makes better decisions than one who is simply told to pick a side.
How an open-cell surface interacts with the build-up, the water table and a lawful outfall — and why the panel supports drainage but cannot substitute for it.
Why 10–20 mm angular stone works and rounded or fine gravel does not, how much to overfill, and what to change on a slope.
Where the panel stops and the sub-base starts, and why the ground under the surface — not the grid — decides the depth of the build-up.
The recurring causes
Almost every failed grid surface comes down to one of four mistakes, and none of them is the panel. The first is an under-sized sub-base: the surface is asked to carry loads the layers beneath were never built for, and it settles. The second is the wrong infill — rounded pea gravel rolls out of the cells, and fine stone clogs until the drainage that justified the system has gone. The third is missing edge restraint, so the outer bays spread and the surface unravels from the perimeter inwards. The fourth is water with nowhere to go: a permeable surface on a heavy clay subgrade with no fall, no geotextile and no outfall simply stores the rain it receives.
Each of these is cheap to prevent and expensive to correct. Reading the installation guide before ordering materials is the single best defence, and the download archive holds the guide exactly as published so every recommendation can be traced to its source. Where a site combines two or more of these risks — soft ground under a slope, say, carrying heavy seasonal traffic — that is precisely when a written review is worth having before the first spade goes in.
More to come
Further pieces are in preparation on grass establishment timings for heavily used routes, edge restraint detailing, and an honest whole-life cost comparison between a grid surface and a hard surface. They will be published with the same rule as everything else: sources named, figures dated, and anything still awaiting approval marked as such rather than quietly omitted.
If there is a question you keep having to answer on site — from a client, an inspector or a supplier — that is the most useful thing you can send us. The best topics here started as a real question from someone standing on a wet driveway.
Deeper reads
Not every question needs a new article. The mechanism behind a failing surface is set out on each solution page — gravel stabilisation explains confinement, grass reinforcement explains shear and establishment, permeable paving explains how water is received by design. The numbers behind a figure live on the testing page, with the condition they were measured in. And the build-up that makes any of it work is in the installation guide, layer by layer, with its approval points. Read those first; if the answer is still missing, it is probably the next topic here.
