Formwork is temporary, but the concrete keeps its shape and surface forever. Most finish defects and many structural ones start here.
Plywood vs Steel
| Film-faced plywood | Steel plates | |
|---|---|---|
| Best for | Beams, columns, sunshades, irregular shapes | Slab soffits |
| Finish | Smooth | Flat; joints may show |
| Reuse | Several to many uses with care | Many uses |
| Cutting to shape | Easy | Limited |
| Weight | Light | Heavier |
Formwork Checklist Before a Pour
- Correct dimensions and levels; camber if specified
- Joints tight or sealed — no gaps for paste to leak
- Release agent applied (not on steel)
- Props plumb, braced, on firm bases, at proper spacing
- Column forms braced against bulging
- Openings and sleeves fixed
- Clean inside — no debris or binding wire offcuts
What Bad Formwork Causes
| Problem | Result |
|---|---|
| Gaps at joints | Honeycombing, sand streaks |
| Weak or few props | Sagging slab, cracks |
| Bulging column forms | Out-of-size columns |
| No release agent | Damaged surface on stripping |
The Short Version
Steel for slabs, plywood for the rest — tight, rigid, level, propped and oiled, and checked before the concrete arrives.
