What is a Pad Stone?
A pad stone is a short, solid stone or block — usually concrete or hard stone — that serves as an intermediate bearing or support, for example beneath a threshold plate, sill, or column. The pad stone spreads a point load over a larger area and prevents the underlying material from cracking or sinking.
Applications
Under a door sill
When fitting a door or window into a masonry opening, the sill is supported by pad stones to prevent it from deflecting.
As a foundation for a column
A concrete pad stone (also: isolated pad foundation) beneath a timber or steel column is a small, standalone foundation that transfers the point load of the column to the ground.
In masonry
In historic masonry, a pad stone is a short block that projects from the wall to support something (a beam, a lintel).
Pad stone vs. pad foundation vs. sill
| Term | What it is | Function |
|---|---|---|
| Pad stone | Short, solid stone/block | Intermediate bearing, point support |
| Pad foundation | Concrete foundation under a column | Carries point or column load |
| Sill | Horizontal threshold at window/door | Water drainage, sealing |
Casting a concrete pad stone yourself
For a timber post in the garden or at a veranda:
- Dig a hole: minimum 600 mm deep (below frost line), 400 × 400 mm wide
- Make formwork from plywood or use a PVC pipe
- Set an anchor plate or stainless steel bolt in the formwork (at the correct height)
- Pour concrete (C20/25 or 1:2:3 mix)
- Allow to cure for at least 7 days before loading
Related terms
- Strip foundation
- Pad foundation
- Sill
- Column / post
- Concrete foundation
- Setting dimension
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