Most decorative precasters use a wet-casting method, as opposed to dry-cast. Wet-cast means that the concrete has a water-cement ratio of about 0.4 or higher. Dry-cast concrete is very dry (w/c of 0.30 to 0.36), has zero slump, and the forms can be stripped as soon as the concrete has been consolidated. Dry-casting requires an expensive dry-casting machine and is typically used for mass production of products like concrete pipe or manholes and also in concrete block production. The big advantage of dry-casting is that you only need one set of forms to mass produce a specific part, since the form can be stripped immediately.