Mortar types (ASTM C270)
A low-strength mortar (min 350 psi) for interior non-load-bearing walls and for re-pointing soft historic brick where a hard mortar would cause damage.
| Designation | Type O |
|---|---|
| Ratio (by volume) | 1 : 2 : 9 |
| Portland cement | 1 part |
| Hydrated lime | 2 parts |
| Sand | 9 parts |
| Typical compressive strength | 350 psi · 2.4 MPa |
| Typical use | Interior non-load-bearing, tuck-pointing, repair. |
A low-strength mortar (min 350 psi) for interior non-load-bearing walls and for re-pointing soft historic brick where a hard mortar would cause damage.
Mortar type matters more than most people expect: a mortar much stronger than the units it beds will transfer movement into the masonry and spall the faces. Pick the weakest mortar that meets the structural and exposure demand.
Need quantities? The volume calculators give the cubic yards, cubic metres and bag counts for the pour this mix goes into.
Applications
Same family