The problem with gravel
A gravel strip weeds over, silts up and clogs up over time. Once the fill is dense, it no longer drains water downward but holds it at the base – exactly the opposite of what is wanted.
The codes have responded: with the package of standards published in June 2026 (DIN 4095-1 and DIN 18533), the guiding principle is “water away from the base” – surface water is carried away from the building across the terrain in a controlled way instead of being drained downward through gravel strips into the backfilled working space.
Where it becomes critical
During heavy rain and backwater, the weakness of the loose fill shows particularly clearly. A connection that drains in a controlled way is the more robust solution here.
The modern alternative
Instead of loose fill, a walkable grating over a ventilated channel provides controlled drainage – low-maintenance, barrier-free and permanently functional. This keeps the base protected, without weeding over and topping up.
