You should be able to press your thumb into the mortar, with the thumb print remaining. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile.
Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. Lime-based putties take longer to set but they won't break bricks. Rick Roger's two-story Georgian has stood for more than 80 years in the prosperous suburb of Evanston, Illinois, north of Chicago.
With its columned portico, brick walls and ivy-covered facade, his house is the image of prewar solidity. Up close, the walls tell another story. Between the brick, slapdash patches of gray mortar clash with the original white. In some places, the brick face has begun to flake off—a sign that water is getting in, freezing and slowly turning the hard red clay into dust.
A dozen 3-foot-long cracks radiate from the windows on the north side, leaving the wall open to water infiltration. Anxious to find out what has gone wrong, Rogers called Mario Machnicki, a mason who specializes in fixing brick and stone walls.
Several weeks later, after a visit to examine the walls, Mario and his younger brother, John, arrive in their red pickup, ready to work. The message at the Rogers house is loud and clear: The mortar is killing it. Not the original mortar, a relatively soft mix of lime and sand, but the previous patch job, which used masonry cement.
The old lime-based mortar had been a perfect partner for the soft, porous brick, flexing to accommodate the brick's slight expansion and contraction. Like all mortars, however, it slowly eroded, and after 60 or 70 years the weathered portion was chiseled out and replaced, a process called repointing or pointing. Unfortunately for this wall, masonry practices underwent a tectonic shift in the s. Brick became harder and more rigid, as did mortar. With the ready availability of portland cement, a material so hard and so impervious to water that it is used to plug leaks in basements, masons abandoned time-consuming lime-based mortars, which set so slowly that no more than seven courses could be done in a day.
Instead, bricklayers adopted fast-setting masonry cement: sand and ground limestone blended together with as much as 65 percent portland cement.
That modern mix was the unyielding cement the previous masons had slapped on the Rogers house joints. Once it cured, the delicate give-and-take of brick and mortar was replaced by a protracted battle-which the old brick was losing. The cement dammed the joints, trapping moisture inside the brick. In winter, the waterlogged walls froze and cracked, allowing still more water to penetrate.
In summer, as the brick tried to expand, its protective fire-skin literally popped off. Americans' reliance on masonry cement surprised him when he arrived here from Poland in He grew up building brick houses without a single grain of cement. The mortar he used contained simply three parts sand to one part lime putty, the ratio established in 10 B.
For the Rogers house, he had the original mortar analyzed so he could order the same recipe. The assay revealed the proportion of lime to sand, the size and color of the sand grains and the compressive strength of the brick. He double-checks his hunches by chiseling out a small piece of mortar and dropping it on the sidewalk.
A piece containing a lot of cement makes a high-pitched ring; a chunk containing mostly lime makes a muffled thud. Offering a high compressive strength of over 1, psi and a high-tensile bond strength, type S mortar is suitable for many projects at or below grade.
It performs extremely well to withstand soil pressure and wind and seismic loads. Type S is the common choice for many below-grade applications, such as masonry foundations, manholes, retaining walls, and sewers, as well as at-grade projects like brick patios and walkways.
Although type S mortar must have a minimum compressive strength of 1, psi, it is often mixed for strengths between 2, and 3, psi. Type M mortar mix has the highest amount of Portland cement and is recommended for heavy loads and below-grade applications, including foundations, retaining walls, and driveways.
While type M mortar provides at least 2, psi of compressive strength, it offers relatively poor adhesion and sealing properties, making it unsuitable for many exposed applications. Type M is preferred for use with natural stone because it offers similar strength to that of stone. Type K mortar is rarely used for new construction but may be specified for restoration or other specialty applications. It offers a very low compressive strength of only about 75 psi.
Because of its softness, type K is primarily used for restoring the masonry on historic or ancient buildings that require a special mix that is not significantly stronger than the existing masonry. Actively scan device characteristics for identification.
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