Mortar is a mixture of cement (or lime), sand, and water used to bond bricks together or to plaster surfaces. After curing, mortar forms a strong, durable bond. The terms ‘mortar mix’ and ‘mortar’ are often used interchangeably — strictly speaking, mortar refers to the cured form of the fresh mix.
Types of mortar
| Type | Composition | Use |
|---|---|---|
| Bricklaying mortar | Cement + sand + water | Laying bricks |
| Pointing mortar | Finer sand + cement + water | Finishing joints |
| Render/plaster | Cement/lime + fine sand + water | Plastering walls |
| Thin-bed mortar | Ready-mixed thin mortar | Aerated concrete blocks, calcium silicate |
| Trass-lime mortar | Trass + lime + sand | Historic masonry, damp-sensitive locations |
Mixing mortar — ratios
| Application | Cement | Sand | Notes |
|---|---|---|---|
| Bricklaying | 1 part | 3-4 parts | Standard bricklaying mortar |
| Pointing | 1 part | 3 parts | Finer sand (0-2 mm) |
| Rendering | 1 part | 4-5 parts | Add lime for workability |
| Foundation | 1 part | 3 parts | Stiff mix, little water |
Tips for mixing
- Dry mix first — Mix cement and sand dry first, then add water
- Add water gradually — Too much water makes the mortar weak and runny
- Consistency — Good when the mortar stays on the trowel without sliding off
- Working time — Use within 1-2 hours, after that the mortar starts to set
Ready-mix mortar
For DIYers, ready-mixed dry mortar (25 kg bags) is easiest: just add water. More expensive per kilo than mixing from scratch, but more convenient for small jobs.
Common mistakes
- Too much water — Mortar becomes too thin, shrinks when curing, poor adhesion
- Wrong sand type — Sharp sand for bricklaying, not builder’s sand (rounded)
- Working too late — After 2 hours, mortar is no longer usable
- Not wetting the bricks — Dry bricks suck the water out of the mortar
Related terms
- Mortar
- Bricklaying
- Bond pattern
- Pointing
- Cement
- Foundation