Pre-mixed mortar bags (Quikrete, SAKRETE, or equivalent) are convenient and ready to use but cost significantly more per cubic foot than site-mixing from Portland cement, hydrated lime, and masonry sand. For a 120-sq-ft brick wall requiring 12.2 cubic feet of mixed mortar, the pre-mixed cost runs about $325 to $378 (27 bags at $12 to $14 each). The site-mix equivalent — 4 bags of 94-lb Portland cement at $16, 2 bags of 50-lb hydrated lime at $8, and 9.4 cubic feet of masonry sand at approximately $25 — totals roughly $100 to $130 in materials, a savings of $200 or more. The trade-off is labor: site-mixing requires more measuring, a mixer or large mortar pan, and experience to achieve the correct consistency. For projects under 50 square feet, pre-mixed bags are almost always faster and more economical when labor is counted. For larger projects, site-mixing saves enough money to justify the setup time. Our calculator shows both options side by side so you can make the actual decision rather than discovering the cost difference at the store.
New construction: wall area (sq ft) times the coverage rate for the selected masonry type. Brick face-shell: 6.75 bricks per sq ft divided by 30 bricks per bag = 0.225 bags per sq ft. Brick full-bed: 6.75/20 = 0.338. CMU face-shell: 1.125/12 = 0.094. CMU full-bed: 1.125/8 = 0.141. Fieldstone: 1/6 = 0.167. Each 60-lb bag yields 0.45 cubic feet of mixed mortar. Repointing mode: 1 bag per 12 sq ft (standard 3/8-in joint raked to 3/4-in depth). Site-mix Type S per cubic foot of mortar: 0.25 bags Portland cement (94 lb), 0.125 bags hydrated lime (50 lb), 0.77 cubic feet masonry sand.
01
Always Use Type S for Exterior Work — Type N Will Fail Outdoors
ASTM C270 defines four mortar types: M, S, N, and O. For any exterior masonry application in the US — brick walls, CMU block walls, retaining walls, veneer, chimneys, or any masonry below grade — Type S is the required specification. Type S has a 28-day compressive strength of 1,800 psi and adequate bond strength for weather-exposed masonry. Type N, with only 750 psi strength, is acceptable only for above-grade, non-load-bearing interior walls such as partition walls in office interiors. Many homeowners and small contractors use Type N for exterior work because it is slightly cheaper and has a better “workability” (it stays soft longer, making it easier to tool joints), but exterior mortar joints made with Type N will erode, crack, and allow water infiltration within 5 to 10 years in freeze-thaw climates. The long-term cost of repointing with proper Type S mortar is far lower than repointing work done prematurely because Type N was used. Our calculator defaults to Type S for this reason.
02
Repointing Mortar Must Be Softer Than the Brick — Never Harder
When repointing historic or older brick masonry (pre-1930s construction in particular), the new mortar must be softer than the brick. This is not optional — it is the foundational principle of historic masonry repair. Old bricks were made with different clay compositions and fired at lower temperatures, making them more porous and slightly weaker than modern face brick. If a hard Portland-heavy mortar (Type S or stronger) is applied to soft historic brick, thermal expansion and freeze-thaw cycling will cause the mortar to force the brick to crack and spall rather than allowing the mortar joint to compress and flex. The correct specification for historic masonry repointing is typically a lime-based or lime-putty mortar with little or no Portland cement — often called “natural hydraulic lime” or NHL mortar — that matches the compressive strength of the original lime mortar. For modern brick (post-1950s), standard Type S mortar is the correct repointing specification. When in doubt about historic brick, consult the National Park Service Preservation Briefs No. 2, which covers repointing of historic masonry in detail.
03
Rake Out 3/4 Inch — Not Just the Surface — Before Repointing
Repointing over deteriorated mortar that has not been adequately removed is one of the most common masonry repair failures. The new mortar must be bonded to solid, sound masonry on three sides — the back of the joint and both brick faces on either side. Standard industry practice is to rake or grind out the old mortar to a minimum depth of 3/4 inch before applying new mortar. At 3/4-inch depth, the new mortar has enough surface area bonded to the brick faces to resist pullout. Repointing at a depth of only 1/4 to 1/2 inch (which is what you get if you just brush or lightly grind the joint) results in a mortar “patch” that has minimal bond area and will loosen and fall out within 2 to 3 freeze-thaw seasons. Use an angle grinder with a tuckpointing diamond blade or a cold chisel and hammer to achieve the full 3/4-inch depth. Wear eye protection and an N95 respirator — old mortar grinding produces significant silica dust.
How many bags of mortar do I need per square foot?+
Coverage rates for 60 lb pre-mixed mortar bags: brick with face-shell bedding (standard) = 0.225 bags per sq ft (about 22.5 bags per 100 sq ft); brick with full mortar bedding = 0.338 bags per sq ft; CMU block with face-shell bedding = 0.094 bags per sq ft (about 9.4 bags per 100 sq ft); CMU block with full mortar bedding = 0.141 bags per sq ft; fieldstone = 0.167 bags per sq ft. For repointing: 0.083 bags per sq ft (about 8.3 bags per 100 sq ft, at 3/8-in joint depth 3/4 in). CMU block requires approximately 2.4 times less mortar per square foot than brick because the CMU face area per block is much larger than the mortar joint area per block.
What is the difference between Type S, Type M, and Type N mortar?+
All three are defined by ASTM C270 (Standard Specification for Mortar for Unit Masonry). Type M is the strongest (minimum 2,500 psi at 28 days) and is used for masonry in direct contact with soil (footings, retaining walls below grade). Type S has 1,800 psi strength and is the standard for all exterior masonry above grade — brick walls, CMU walls, chimneys, veneer, and any wall subject to weather or structural load. Type N has 750 psi strength and is suitable only for above-grade, non-load-bearing interior masonry such as partition walls. Type N should never be used for exterior work. The letter sequence M-S-N-O is derived from the original five-type specification (M-S-N-O-K, skipping alternate letters from M-A-S-O-N-R-Y). Pre-mixed bags of each type are widely available at US home improvement stores; Type S is the most common residential specification.
What is the site-mix recipe for Type S mortar?+
Type S mortar by volume (one batch): 1 part Portland cement to 0.25 parts hydrated lime to 2.75 parts masonry sand. For a standard mixer batch, this translates approximately to: 1 bag (94 lb) Portland cement, 1/4 bag (12.5 lb) of Type S hydrated lime, and approximately 3 to 4 cubic feet of masonry sand. Add water slowly until the mortar reaches a smooth, plastic consistency that holds its shape when sliced with a trowel but is moist enough to bond to dry brick. The water-to-cement ratio should be as low as possible while maintaining workability — excess water weakens the mortar and increases shrinkage cracking. Mix only as much mortar as can be used within 1.5 to 2 hours; discard mortar that begins to stiffen and never add water to re-temper mortar that is more than 2 hours old.
How much mortar do I need to repoint a wall?+
For standard modular brick repointing with joints raked to 3/4-inch depth: 1 bag of 60 lb Type S mortar covers approximately 10 to 15 square feet of wall face, with 12 square feet per bag being the standard estimate. This is significantly less mortar than new construction because repointing fills only the outer 3/4 inch of the joint rather than the full mortar bed behind the brick (which is typically 4 to 5 times deeper than the 3/4-inch repointing depth). For a 120-sq-ft wall: 10 bags of 60 lb mortar for repointing vs 27 bags for new construction. Coverage varies significantly with joint width and depth — wide, deeply deteriorated joints require more mortar; narrow joints in good condition with only surface deterioration need less.
What is the difference between face-shell bedding and full mortar bedding?+
Face-shell bedding applies mortar only to the two outer shell strips of a hollow CMU block or to the full face of a solid brick, leaving the web areas (the internal cross-webs of hollow CMU blocks) without mortar. This is the standard residential and commercial masonry practice and uses approximately 1 bag of mortar per 12 CMU blocks or 30 bricks. Full mortar bedding applies mortar to the entire block or brick face including the cross-webs, and is required for: masonry below grade in contact with soil or water, highly loaded structural CMU walls, certain seismic design requirements, and where the masonry code specifically calls for full bedding. Full mortar bedding uses approximately 1 bag per 8 CMU blocks or 20 bricks — about 50% more mortar than face-shell bedding. Our calculator provides separate coverage rates for both bedding methods.
How long does pre-mixed mortar last before it hardens?+
Pre-mixed mortar (Type S or Type N in bags) has a working time of approximately 1.5 to 2 hours from the time water is added, at normal temperatures of 50 to 85 degrees Fahrenheit. In hot weather (above 85 degrees F) the working time may decrease to as little as 45 to 60 minutes, especially in direct sun. In cool weather (40 to 50 degrees F) the working time extends to 2 to 3 hours. Mortar that begins to stiffen can be re-tempered once by adding a small amount of water and remixing, but only within the first 2.5 hours from initial mix — beyond this, the chemical set has begun and the mortar must be discarded. Never re-temper mortar a second time. Mix only the amount of mortar you can use in 1 to 1.5 hours to avoid waste and ensure consistent joint quality throughout the work session.
Can I use concrete mix instead of mortar?+
No. Concrete mix and mortar are chemically different products designed for different applications. Concrete mix contains coarse aggregate (gravel or crushed stone) that prevents it from filling mortar joints properly — the large aggregate particles cannot flow into the narrow joints between bricks or blocks and create voids, weak spots, and poor bond. Concrete mix also lacks the plasticity and workability of mortar, making it difficult to apply and tool. The Portland cement in concrete is also typically a much higher proportion than in mortar, resulting in a very hard, inflexible final product that cracks under the thermal movement of masonry walls. Always use purpose-mixed mortar (pre-mixed Type S bags, or Portland plus lime plus sand site-mixed to the ASTM C270 ratios) for any brick, block, or stone masonry application.
What is the coverage of one 60 lb bag of mortar?+
One 60 lb bag of pre-mixed Type S mortar yields approximately 0.45 cubic feet of mixed mortar. In practical coverage terms: for brick (face-shell bedding): 30 bricks, or approximately 4.4 sq ft of wall face. For CMU block (face-shell bedding): 12 blocks, or approximately 10.7 sq ft of wall face. For repointing standard brick: approximately 12 sq ft of wall face. These are average values — actual coverage varies with mortar joint width, mason skill, and the amount of drop or waste. Most experienced masons add 10% to the calculated bag count to ensure they do not run short during a session.
What is tuckpointing vs repointing?+
In the US, repointing and tuckpointing are often used interchangeably to describe the same process — raking out deteriorated mortar joints and replacing them with fresh mortar. In the British and historic masonry tradition, tuckpointing has a more specific meaning: it refers to a decorative technique where contrasting-colored mortar is applied over plain mortar joints to create the appearance of very fine, precise joints. The main layer of mortar is colored to match the brick, and then a thin strip of contrasting colored lime putty mortar (the “tuck”) is pressed into a narrow groove in the main mortar to simulate a fine joint line. In everyday American usage, “tuckpointing” almost always simply means raking and repointing deteriorated joints. Our repointing mode calculates mortar for the standard process of raking and refilling deteriorated joints, which is the same regardless of whether you call it repointing or tuckpointing.
How do I color mortar to match existing mortar?+
Mortar color matching requires both the correct mortar composition and the correct colorant. Pre-mixed mortar bags are available in standard colors (buff, tan, charcoal, and white in addition to standard gray), but these rarely match weathered mortar exactly. For a close match: take a sample of the existing mortar (chisel out a small piece from an inconspicuous area) and bring it to a masonry supply house to match color. Integral masonry colorants (iron oxide pigments) are added to white Portland cement plus white masonry sand to achieve custom colors. White Portland cement and white sand as the base provides much better color accuracy than standard gray Portland, which adds a gray undertone to any color. Test the color match on a small area and allow it to cure fully before evaluating — mortar colors shift significantly from wet to dry during the first 48 to 72 hours of curing. For historic structures, never sandblast or acid-wash existing mortar before repointing, as this changes the surface texture in ways that make color matching even harder.
How do I know when mortar joints need repointing?+
Mortar joints need repointing when: the mortar has recessed more than 1/4 inch from the brick face (the joint feels soft or hollow when pressed), the mortar crumbles when probed with a screwdriver or masonry chisel, the joint surface has horizontal cracks or open fissures, efflorescence (white mineral deposits) has stained the brick face above the joints indicating water infiltration through the mortar, or the mortar surface has eroded to a thin shell that sounds hollow when tapped. In the Northeast and Midwest US, masonry joints on older homes (pre-1960s) often need repointing every 25 to 50 years due to freeze-thaw weathering. In the South and Southwest, mortar joints last 50 to 100 years. Any exterior masonry wall showing water staining on the interior side should have all mortar joints inspected immediately, as mortar deterioration is a common cause of water infiltration through brick walls.
What is masonry sand and can I use regular sand in mortar?+
Masonry sand (also called mortar sand or washed sand) is a fine, well-graded angular sand with particle sizes between approximately 0.06 and 0.3 millimeters. It is specifically processed to have a consistent gradation that provides good workability and bond strength in mortar. Regular play sand (rounded quartz particles), beach sand (salt contamination), or construction fill sand (too coarse or poorly graded) should not be substituted for masonry sand in mortar — they produce weaker, less workable mixes that may not meet ASTM C270 standards. Masonry sand is widely available at masonry supply houses and concrete suppliers by the cubic yard or in 50-pound bags. When site-mixing mortar, always use masonry or mortar sand specifically labeled for the purpose. Our site-mix calculation outputs the cubic feet of masonry sand needed for the equivalent of the pre-mixed bag quantity.
How long does mortar take to cure?+
Type S mortar reaches initial set (firm enough to hold the masonry units in place without movement) in approximately 4 to 8 hours. The joint can be tooled (compressed and shaped) when the mortar has firmed to a “thumbprint hard” consistency, usually 30 to 90 minutes after placement depending on temperature and humidity. Mortar reaches 70% of its design strength at 7 days and approximately 90% at 28 days. For structural applications, do not apply loads to the masonry until at least 7 days have elapsed and the mortar has cured adequately. Protect fresh mortar from rain for at least 48 hours (covering with plastic sheeting or burlap), from direct sun and drying wind for the first 3 to 7 days, and from freezing temperatures for the full 28-day cure period. In cold weather (below 40 degrees F), mortar curing slows dramatically and temperatures below 32 degrees F can prevent cure entirely and damage fresh mortar — use insulating blankets and monitor temperatures when working in cold weather.
Is pre-mixed mortar or site-mixed mortar stronger?+
Both pre-mixed Type S mortar and site-mixed Type S mortar (1 Portland : 0.25 lime : 2.75 sand by volume) are designed to meet the same ASTM C270 Type S strength specification of 1,800 psi at 28 days. The actual strength depends on the water-to-cement ratio and the consistency of mixing rather than whether the mortar was pre-mixed or site-mixed. In practice, pre-mixed bags provide more consistent results because the proportions are pre-measured and the bag formulation is tested for consistency. Site-mixed mortar is more variable because it depends on the skill of the mason in measuring proportions and adding the correct amount of water. For projects where strength consistency is critical (structural masonry, below-grade applications, or high-seismic-zone construction), pre-mixed bags are the more reliable choice. For large residential or commercial projects where cost is a factor, site-mixed mortar with careful proportioning by volume is an economically viable alternative.
What is masonry cement and how is it different from Portland cement?+
Masonry cement is a pre-blended product that combines Portland cement with lime and air-entraining agents in a single bag. It is designed specifically for mortar use and eliminates the need to purchase Portland cement and hydrated lime separately. To make mortar with masonry cement, you add only masonry sand and water (no separate lime required). Masonry cement Type S mortar is made at a ratio of 1 part masonry cement to 3 parts masonry sand by volume. One 70-lb bag of masonry cement Type S makes approximately the same amount of mortar as one 94-lb bag of Portland cement plus one 50-lb bag of hydrated lime mixed together, but at lower total weight and cost per batch. The air-entraining admixtures in masonry cement improve workability and freeze-thaw resistance compared to plain Portland-lime mortars. Portland cement is the base binder used in both concrete and mortar; it must be combined with lime and sand to make mortar. Never use Portland cement alone as a mortar — the resulting mix is too stiff, too strong, and lacks the bond strength and flexibility of properly proportioned mortar.
How much does it cost to have a brick wall repointed?+
Professional repointing costs in the US typically run $5 to $25 per square foot of wall face, depending on mortar joint size, wall accessibility, and local labor rates. For a standard residential brick wall with 3/8-inch joints: smaller jobs under 200 sq ft often have minimum charges of $500 to $1,000 regardless of area. Larger repointing jobs on 1,000 sq ft or more typically run $8 to $15 per sq ft in most US markets. High-rise or hard-to-access walls requiring swing staging or scaffolding add $5 to $10 per sq ft for the rigging alone. DIY repointing materials for a 120-sq-ft wall using pre-mixed mortar bags run approximately $120 to $140 (10 bags at $12 to $14 each) plus a renting an angle grinder with tuckpointing blade for about $60 per day. The primary cost driver for professional repointing is the labor to properly rake out joints — this is slow, physically demanding work that requires care to avoid damaging the brick faces.