Choosing Brick and Mortar for Brick Veneer: Grades, Types, and Mortar

Choosing brick and mortar for a veneer wall is two linked choices. The brick must suit the weather it will face, and the mortar must suit the brick and the work the wall has to do. Record both choices, with the size and joint width, before ordering, so the order names the exact products instead of a colour and a guess.

Which brick should a veneer wall use?

Use facing brick, specified under ASTM C216, for the exposed face. Building brick under ASTM C62 carries a durability grade but no appearance type, so it does not control the face the way facing brick does. A veneer face needs both: a grade for weather and a type for appearance.

Grade is the weather decision. Grade SW is severe weathering, for brick exposed to freezing while saturated with water. Grade MW is moderate weathering, for brick exposed to freezing but unlikely to be saturated. Facing brick has no Grade NW, so a grade labelled NW on a veneer order is a wrong specification, not a cheaper option.

Type is the appearance decision. Type FBS is general use. Type FBX has tighter dimensional tolerances, for work where uniform size matters. Type FBA allows more variation in size and texture, for brickwork meant to show that variation. Pick the type from the look the wall is meant to have, not from the grade, because grade and type answer different questions.

Thin veneer brick is a different product. It follows ASTM C1088, which grades units Exterior or Interior instead of SW and MW, and it is not laid as full brick veneer. Do not carry a full-veneer grade, coverage rate, or mortar assumption to a thin veneer job.

How do you match the grade to the exposure?

Start from the exposure of the actual wall: whether it will freeze while wet, how often it stays saturated, and what the project documents say. A parapet or a wall at grade stays wet longer than a sheltered upper wall, so two walls on one house can justify different checks. No source in this pack assigns a grade to a named town or region, and this page does not either.

Where the exposure check is unclear, write the uncertainty on the record and confirm the grade with the project designer or the brick supplier before ordering. Ordering first and checking later leaves the wrong grade in the wall, and a grade cannot be corrected after laying.

Which mortar type should a veneer wall use?

Use the mortar type the project documents name. Where the documents are silent and the work is normal above-grade veneer, the Brick Industry Association names Type N for normal use, including most veneer applications, and directs type selection to its Technical Note 8B. Type N is the starting point for ordinary veneer, not a default for every wall.

Mortar types under ASTM C270 are strength grades, measured as minimum average 28-day compressive strength of laboratory-prepared mortar. A higher number is not a better mortar for veneer. It is a stiffer mortar, and stiffness is a cost when the wall needs to move a little without cracking.

Type S belongs where the design needs its strength, such as a structural or high lateral-load condition. Type M belongs below grade and in heavy-load masonry. Type O is a low-strength, lime-rich mortar for low-stress work and for soft brick that a stronger mortar would damage. None of those calls follows from the strength number alone. Each follows from the wall duty and the project specification.

What goes into the mortar?

Mortar under ASTM C270 can be specified two ways. The proportion specification is a recipe: fixed parts of each ingredient. The property specification is a tested result: the mixed mortar must meet the strength, water retention, and air content limits in the standard. For typical project requirements, the Brick Industry Association points to the proportion specification, and a preblended dry mix must comply with ASTM C1714.

The familiar cement-lime proportions are 1 part cement to 1/4 part lime to 3 parts sand for Type M, 1 to 1/2 to 4 1/2 for Type S, 1 to 1 to 6 for Type N, and 1 to 2 to 9 for Type O. Under the proportion specification, the sand is not less than 2 1/4 times and not more than 3 times the sum of the cementitious volumes, and each familiar ratio falls inside that range. A bagged mortar does not necessarily follow these site-mixed proportions, because the manufacturer formulates it, so read the bag instead of assuming the ratio.

The ingredients matter as much as the ratio. Use cement that complies with ASTM C150, C595, or C1157, hydrated lime that complies with ASTM C207, and sand that complies with ASTM C144. The Association recommends only Type S hydrated lime in mortar. Use potable water, free of deleterious materials. Masonry cement under ASTM C91 and mortar cement under ASTM C1329 are separate cementitious materials with their own types and air-content limits, so do not treat a masonry cement bag as a cement-lime recipe.

How do you check the colour before ordering?

Mortar colour comes from the cement, the sand, and any pigment, not from the type letter. Two Type N mortars can look different because their sands differ. Judge the colour on a sample panel built with the actual brick and the actual mortar, viewed in daylight, not on a single brick and not on wet mortar, which darkens as it dries.

Use as little pigment as possible. The Association limits metallic oxide pigments to 10 percent of cement content by weight and carbon black to 2 percent, halved when the cement is masonry cement or mortar cement. Avoid pigments containing Prussian blue, cadmium lithopone, and zinc and lead chromates. A pigment that changes the colour also changes the mix, so a colour decision made after laying cannot be undone without rebuilding the joint.

A complete selection record

The record below is an example of a complete record, not a specification for any real wall. A real wall takes its grade from its exposure check and its mortar type from its project documents.

Hand this record to the measuring step, so the measured net area is priced against the named brick and joint, and to the ordering step, so waste and packs are calculated for the same products. A record missing the grade, the type, or the joint width is not ready to order from.

Selection mistakes that cost a wall

• Ordering building brick for an exposed face, with no appearance type to control it.
• Writing Grade NW on a facing-brick order, when ASTM C216 has no NW grade.
• Defaulting to the strongest mortar, and laying a stiff joint where the wall needed a forgiving one.
• Judging mortar colour from wet mortar or a single brick, instead of a sample panel.
• Treating thin veneer brick as full veneer, and carrying the wrong grade and coverage with it.
• Ordering before the record names the grade, the appearance type, the size, the joint, and the mortar type.

Safety and professional scope

Selecting a brick and a mortar plans materials only. It does not design the veneer system, select ties, flashing, drainage, or support, and it does not approve a wall for construction. Those decisions rest with the project team named in Technical Note 10.