Page "Underpinning" Paragraph 14

Mini-piled underpinning schemes include pile and beam, cantilever pile-caps and piled raft systems.

Cantilevered pile-caps are usually used to try and avoid disturbing the inside of a building and require the construction of tension and compression piles to each cap.

These are normally linked by a beam.

The pile and beam system usually involves constructing pairs of piles on either side of the wall and linking them with a pile cap to support the wall.

Again, the pile caps are usually linked by reinforced concrete beams to support the entire length of the wall.

Piled raft underpinning systems are commonly used when an entire building needs to be underpinned.

The internal floors are completely removed, a grid of piles is installed and a reinforced concrete raft is then constructed over the complete floor level, picking up and fully supporting all external and internal walls.