Securing the installation – We run many installations in the trenches outside the building – gas, water supply, sewage or electric. It is always a good idea to put them on a drainage layer, even thin from small ones . pebbles or washed gravel. However, it is absolutely necessary to lay stone or concrete slabs on top of the drainage layer and then backfill the trench. The boards will protect the installation from being damaged in the event of, when we dig other ditches or trenches. This will be especially important when excavating with machines.