The most favourable soils for screw piles are clay and sandy soils. Owing to the large surface area of the helix, a screw pile has a better carrying capacity than standard steel piles. The good carrying capacity means that adequate capacity is attainable even in layers of clay or sand. Screw piles do not often need to be installed as deep as in piledriving, and thus both the length and costs of the piles are often lower thanin pile-driven foundations. Also, installation of screw piles succeeds best inclay and sandy soils. With machine installation, screw piles can be installedalso in moraines.