Abstract: Method for constructing a filling station, having a number of storage tanks, one or more pump islands with a number of pumps on each pump island, and also lines, such as the lines for the supply of the necessary oil and petrol from the storage tanks to the pumps, and for the discharge of rainwater and/or spilt product, and a floor surrounding the pump island. First of all a ground slab is made in one piece by monolithic construction, at the same time a number of facilities being provided in the slab, such as fixing means at the position of the so-called islands where the pumps are placed. In the ground slab near the top side a recess or trench and in the trench lines are then placed, and the structures such as pump islands, pumps and possibly a canopy are fixed to said slab.