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Keep up to dateTABLE 1: MORTAR MIXES | |||||
This table lists four types of mortar based on Portland cement as a binder and the proportions, by volume, of the constituents in various mixes. Mixes are grouped in four designations of approximately equal strength and durability. | |||||
Type of mortar | Ìý | Cement:lime:sand | Masonry cement:sand | Ìý | Cement:sand (plasticised) |
Binder content | Ìý | Portland cement and lime, with or without air entraining additive | Masonry cement containing Portland cement and lime in approx. 1:1 ratio, and air entraining additive | Masonry cement containing Portland cement (min 75%) and inorganic materials other than lime and air entraining additive | Portland cement and an air entraining additive |
Designation | (i) | 1:0 to 0.25:3 | - | - | - |
Ìý | (ii) | 1:0.5:4 to 4.5 | 1:3 | 1:2.5 to 3.5 | 1:3 to 4 |
Ìý | (iii) | 1:1:5 to 6 | 1:3.5 to 4 | 1:4 to 5 | 1:5 to 6 |
Ìý | (iv) | 1:2:8 to 9 | 1:4.5 | 1:5.5 to 6.5 | 1:7 to 8 |
Note: The range of sand volumes noted in this table allow for the differences in grading on the void volume. The lower volumes apply to Type G graded sands of BS 1199 and 1200 and the higher volumes to Type S. Mortar with both lime and air entrainment can be used with any sands within grading defined in BS 1199 and 1200. |
TABLE 2: BRICK AND MORTAR SPECIFICATIONS | ||||
This table offers the appropriate specification of clay bricks and mortar for various building types | ||||
Situation | Brick durability | Ìý | Mortar designation | Remarks |
Ìý | BS 3921 | EN 771-1 | Ìý | Ìý |
Work below or near external ground level | ||||
Low risk of saturation, with or without freezing | FL, FN, ML or MN | F1 or F2: S1 or S2 | (i), (ii) or (iii) | Ìý |
High risk of saturation, with freezing | FL FN F2: | F2: S2 S1 | (i) or (ii) (i) or (ii*) | * with SRPC |
Drainage manholes | FL, FN, ML or MN | F1 or F2:S1 or S2 | (i) | Ìý |
External walls of buildings (unrendered) excluding chimneys, parapets, cappings, copings and sills | ||||
Low risk of saturation | FL, FN, ML or MN | F1 or F2:S1 or S2 | (i), (ii) or (iii) | Ìý |
High risk of saturation | FL FN | F2: S2 F2: S1 | (i) or (ii) (i) or (ii*) | * with SRPC |
Parapet walls (unrendered) | ||||
Low risk of saturation, e.g. low parapets with copings on some single storey buildings | FL or ML FN or MN | F1, F2: S2 F1, F2: S1 | (i), (ii) or (iii) (i), (ii*) or (iii*) | * with SRPC |
High risk of saturation, e.g. where only a capping is provided | FL FN | F2: S2 F2: S1 | (i) or (ii) (i) or (ii*) | * with SRPC |
Cappings, copings and sills | ||||
Cappings, copings and sills | FL or FN | F2: S1 or S2 | (i) | Bed DPCs under cappings, copings and sills in the same mortar |
Freestanding garden walls | ||||
With coping | FL or ML FN or MN | F1, F2: S2 F1, F2: S1 | (i), (ii) or (iii) (i) or (ii) | (ii) mortar with SRPC in exposed locations |
With capping | FL FN | F2: S2 F2: S1 | (i) or (ii) (i) or (ii) with SRPC | Ìý |
Earth retaining walls * Backfilling with free-draining material is strongly recommended | ||||
With coping and waterproof membrane on retaining face | FL or ML FN or MN | F1, F2: S2 F1, F2: S1 | (i) or (ii) (i) or (ii*) | * with SRPC |
With capping, or with coping but no waterproof membrane on retaining face | FL or FN | F2: S1 or S2 | (i) | A waterproof membrane on the retaining face is strongly recommended |
Note: BS 3921: 1985, the British Standard Specification for Clay Bricks, is in the process of being replaced by BS EN 771-1: 2003, the European Standard for Clay Masonry Units. They will run concurrently until early 2005. | ||||
Key | ||||
Designation letters for brick durability and soluble salts content differ between BS 3921 and EN 771-1. | ||||
In BS 3921:1985 | ||||
Brick durability: F=frost resistant M=moderately frost resistant O=not frost resistant | ||||
Soluble salts content: L=low soluble salts content N=normal soluble salts content | ||||
In BS EN 771-1:2003 | ||||
Brick durability: F2=severe exposure F1=moderate exposure F0=passive exposure | ||||
Soluble salts content: S2=lower content category S1=higher content category S0=No requirement category | ||||
SRPC=Sulphate resisting Portland cement |
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