A ‘Conventional’ Raft Slab is a concrete base with thickened beams laid directly on the base.
This photo shows the base covered in poly and with reinforcement in position ready for placing of concrete.
- Better thermal mass, and incorporates thermal mass of ground so better suited to passive solar design.
- Less susceptible to bad workmanship by concretors
- More resistant to point loads, such as jacking a car.
- A thicker overall slab makes it easier if you want Floor Drains (To allow for the dropped floor in those rooms)
- Generally uses more concrete, than ‘Waffle Pod Slabs‘, with more waste as volume is less predictable
- Trenches excavated in the base, that can fill with rain causing delays
- More complicated excavation with additional cost
Also see Ground Conditions