Jointing Materials

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Types and Durability

Description

Mortar

 Expected Lifespan

(Years)

 Adjustment Factors
External
Premixed Mortar

Ready mixed lime: sand for mortar

For gauging with cement should conform to BS 4721

 35+ 1st stage adjustment factor:

In industrial areas (heavy polluted): -15% years

In urban areas: -10% years

In suburban areas: -0% years

2nd stage adjustment factor:

Within 20m from express way: -20% years

Within 20m from major arterial road: -10% years

Within 20m from light traffic road: – 5% years

Test certificate from approved local testing authority : +15% years
Retarded ready to used mortar

Ready to use retarded cement: lime: sand and cement: sand mortar should conform to BS 4721

 35+
Dry pre-packed cementitious mortar mixes

Dry prepacked cementitious mortar mixes should conform to BS 5838-2

 35+
Mixed on site Mortar

With material conform to BS 5628-3: 2001 clause 4.3.

 30
Unclassified, i.e. Mortar with less than above specification < 30

Combination of adjustment factors (1st stage and 2nd stage) should be added to obtain the durability values. Refer to durability calculator.

Notes:

  • Mortar air-entrained agents which entrain air in a mix provide an alternative to lime for imparting improved working qualities to lean cement: sand mixes. In effect, the air bubbles serve to increase the volume of the binder paste, filling the voids in the sand, and this improves the working qualities.
  • The benefit of air-entrainment can be obtained by the use of air-entrained cement: sand mixes, or by the use of mixes based on masonry cement.
  • All factory-made and masonry cement-based mortars are air-entrained (conform to BS 4887: Part 1: 1987).
  • Wet ready to use mortar requires no further mixing and is stored in tubs on site.
  • Dry ready to use mortar delivered in silos or bags, which requires only the addition of mixing water
  • Ready mixed lime: sand mortar is pre-batched materials that are delivered to site, with cement and water being added prior to application.