From 300 mm to 150 mm Raft foundations (also known as raft footings or mat foundations) are made out of reinforced concrete slabs of uniform thickness (usually 150 mm to 300 mm) that span a large area, frequently covering the full footprint of a structure. The purpose of this type of foundation is to provide stable support for a building above it. A raft foundation does not penetrate far into the ground because there is no need to when using reinforced concrete. The strength of a raft foundation comes from the reinforcing in the form of metal cages embedded inside the slab. These reinforce the whole structure and prevent it from collapsing under its own weight. The slab's width determines how much weight it can bear before it needs rebounding or reinforcement. A single raft slab cannot support a heavy building load but several slabs back-to-back can. They also act as thermal breakers during cold weather so information about how many inches of ice cover the river will determine how many rafts need to be ordered. Raised Garden Beds: Raised garden beds are convenient because they allow you to grow a variety of plants that wouldn't otherwise fit in your yard. You can also add color and interest to your yard with different types of plants in each bed. However, raised beds are only useful if you have enough space to fill them with soil.