In masonry buildings using clay or concrete brick as the primary wall element, efflorescence or lime run is an occasional cause for an interesting jobsite meeting. If the staining is occurring at the base of the wall or above / alongside openings or above shelf angles, the problem is often poor drainage.
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Masons and cleaning contractors have at least two cleaners based on hydrochloric acid (HCl) for removal of excess mortar from new clay brick and unpolished Indiana Limestone and at least one cleaner based on phosphoric acid (H3PO4) for use when the substrate is calcium silicate, concrete brick, burnished block or onyx.
Concrete masonry units are known for high compressive strength and tensile strength to carry heavy loads and resist high wind loads. They have the ability to be manufactured beyond their typical strength design by the block supplier with additional cement or aggregates within the mix to carry even heavier loads.
The key component for the strength of masonry walls is the blocks, commonly referred to as concrete masonry unit (CMU). CMU can be specified as normal weight, medium weight, or light weight. In Illinois, particularly in the Chicago metro area, the most common CMU is Medium weight. However, both Normal weight and Light weight can also be specified and used.
Have you seen a building with the brick falling off? How about many cracks on the veneer at the exterior?
One item in the masonry tool bag that seems to be getting more popular as our buildings age, are helical wall tie anchors. These ties are unique and can be used in many masonry repair solutions. The anchors have the ability to stabilize a masonry façade that is failing and they can be used to eliminate vertical cracking in a masonry wall. Anchors are manufactured under several different names such as Helifix, Heli-tie, Spira-Loc and Stich-Ties.
When designing concrete masonry walls, one aspect that needs to be considered is the location of control joints. Control joints are continuous vertical mortar joints where a bond breaker is placed between the mortar and the units on one side. Masonry walls, like concrete walls, will shrink after placement due to moisture content and temperature changes.
Masonry walls are quite versatile in building applications and are common industry wide. What happens, though, when a building retrofit or expansion requires an existing masonry wall to now become a shear wall or for an existing shear wall to now resist more load than its current capacity?
This article, Part 2 of the series, will focus on code requirements, foundation design considerations of sliding and overturning resistance, and external reinforcement options when increasing shear load demand onto existing walls.
The reason for re-pointing is that mortar lasts roughly between 25-50 years while brick lasts approximately 100+ years. Over a buildings life, foundations settle, caulking becomes dry and brittle, mortar joints crack or deteriorate and water finds it’s way into the masonry and beyond.
Masonry wall construction consists of an assembly of several parts – concrete masonry units (CMU), mortar, grout, etc. Based on design requirements, steel reinforcement may or may not be included within the wall. For either situation, continuity of the masonry wall is recommended to tie the full masonry structure together. Bond beams are a very common method to achieve this desired continuity to allow all masonry wall segments to work together as a single unit. This insight will discuss the use and detailing of bond beams in masonry walls.
When masonry construction is conducted under either of these conditions, it is important to have an understanding of the effects of temperature (both ambient and mean daily) and wind, as well as an understanding of the influence these environmental factors have on masonry and mortar properties, construction practices, and economics.
Diaphragm walls are composed of two wythes of masonry with a large cavity or void. The wythes are bonded together with masonry ribs or crosswalls in such a way that, structurally, the wythes function compositely—as though the entire thickness is effectively solid.
Masonry construction has been the material of choice extensively throughout the architectural world for years. And for good reasons. Dollar for dollar, it provides one of the best returns on your construction investment. Today, your choice between masonry construction and any other alternative is easy.
Providing safe structures for people during storm events requires many specific design provisions not typically needed for a standard building that must be coordinated with the entire design team. Masonry is a great option due to the inherent strength, durability, and fire resistance of the material as well as being largely available throughout the U.S.
Article by Cathleen Jacinto, PE, SE, Forse Consulting LLC
The Masonry Advisory Council gets several calls each year regarding the acceptability of masonry. An owner or architect thinks that something, about the masonry, does not look right! Was it installed correctly? Is it within the specification? Where are the guidelines for what is acceptable masonry?
Fall Protection in Construction – Rules for construction by OSHA
OSHA recognizes that incidents involving falls are generally complex events, frequently involving a variety of factors. Consequently, the standard for fall protection deals with both the human and equipment-related issues in protecting workers from fall hazards. This publication is intended to help workers and employers better understand the Fall Protection in Construction standard’s requirements and the reasons behind them.
By Cathleen Jacinto, Forse Consulting
When designing concrete masonry walls, one aspect that needs to be considered is the location of control joints. Control joints are continuous vertical mortar joints where a bond breaker is placed between the mortar and the units on one side as shown in Figure 1.
Grout for reinforced masonry walls is usually specified to meet the requirements of ASTM C 476. Only fine aggregate (sand) is allowed in fine grout, while coarse grout can contain up to 35% coarse aggregate. The aggregate used in masonry grout is specified according to ASTM C 404, and all coarse aggregate for masonry grout must be able to pass through a screen with 1⁄ 2- inch-square openings, making it equivalent to a 3 ⁄ 8-inch aggregate.
Corrugated wall ties are only allowed, by code, to be used in veneer work on wooden studs. If brick is veneered over concrete block, or concrete backing- only wire anchors, adjustable anchors or joint reinforcement is allowed by code. That is the LAW!
When we have a brick veneer over a wood frame and the designer chooses to have a wall begin with a brick veneer at the base and then transit on to another material such as wood or vinyl siding, the uppermost course of brick should be detailed with the same consideration as a window sill.
In today’s building climate, 4-6 story multifamily and office structures are common to the suburban Chicagoland landscape. Many builders wisely choose fire-resistance rated masonry walls and concrete plank floors for these structures. When it comes to roof construction, however, concrete is often overlooked in favor of a more aesthetically pleasing pitched roof system.
To secure masonry veneer to a backup system or to connect two or more masonry wythes, wall ties—made of wire or sheet metal—are necessary. Horizontal joint reinforcement also can be used to tie wythes together. But how do you choose from the thousands of available shapes, sizes, gauges, and steel types of masonry wall ties?
Many factors influence the method a contractorchooses to place grout in a reinforced masonry wall. The volume of grout involved, the number and location of door and window openings, and the type and size of masonry units all must be considered. But many contractors agree that grouting a wall a full story at a time is the most efficient method, and say they prefer it whenever conditions make it feasible. Architects and engineers recommend it as a way to eliminate cold joints in the grout that can weaken the wall.
The introduction of a Concrete Masonry banding in a clay brick veneer wall is a popular design element, as it is for using concrete masonry veneers for entire walls. Using 4”split face units, ground faced units, glazed block, half high concrete masonry units or simulated stone units made of concrete are all commonly used as a banding course or courses within a brick wall.
Getting mortar into a thin joint between already-placed units can be a difficult, messy and expensive operation. Some innovative companies, however, have developed equipment that eliminates much of the agony. This equipment comes in different levels of complexity and cost. The size and complexity of a project dictates which is most appropriate.
Commonly called “tuckpointers’ grinders,” small disc grinders are indispensable tools for repair contractors who do a lot of work repointing masonry. These electric-powered right angle grinders allow hardened mortar to be cut out quickly and efficiently.
Identify elements of a masonry wall that should be identified in a mock-up panel. Describe how mock-up panels can improve the outcome of a project. Consider criteria of ASTM C216 and their impacts on a project.
Brick with initial rate of absorption (IRA) less than 5gm/min/30 in2 can be used successfully when laid in mortar having low water retention. In this research program, brick with IRA near 1 gm/min/30 in2 and 4 gm/min/30 in2 were combined with seven different mortars.
Outdoor Stairs and brick walls: the good, the bad and the ugly.
For a cavity wall to function properly, water that collects on flashing must be able to drain through weep holes to the exterior of the building. If weep holes do not function properly, water collecting in the cavity can infiltrate to the building’s interior. For proper drainage, cavity walls must be detailed correctly and constructed to keep the cavity clear of mortar droppings and prevent weep hole blockage.
Re-anchoring brick saves money! When wall ties are missing or corroded or brick headers are broken, the exterior brick or portions of it can fall from the building
In a properly designed and constructed masonry wall, mortar joints can last 50 years or more without maintenance. Eventually, though, natural weathering by wind and rain will cause the mortar to erode. Inferior original materials or workmanship, design flaws, or traumatic damage to the building can hasten mortar deterioration.
To an architectural preservationist, the worst scenario imaginable is a masonry wall where the mortar joints surround deep impressions, pockets of eroded brick or stone. This indicates that little or no consideration was given to compatibility when the wall was repointed.
The maximum horizontal spacing between vertical control joints in concrete masonry walls is determined by: the local average annual relative humidity, whether the concrete masonry units are moisture controlled or nonmoisture controlled, as defined by ASTM C 90, the vertical spacing of bed joint reinforcement, exposure to weather.
Moisture entering buildings has the potential to cause problems for the health and well-being of the building inhabitants if the building envelope is not designed and constructed properly. Thus, the flashing of masonry for exterior openings is tremendously important to architects, engineers, and contractors.
When joints are weathered but not badly deteriorated, this technique can stop leaks more economically than repointing.
3 Points of Interest: Major changes in design using steel studs and rigid insulation, tolerance in masonry related to poured concrete foundations, good limestone cap details to be shared and learned.
The purpose of this publication has the following objectives: (1) to offer support for upgrading local building codes that will increase the fire safety of LRMFD’s, (2) to examine the superior performance of masonry and concrete under standard fire test conditions versus that of other types of building construction commonly used in LRMFD’s, (3) to show that masonry and concrete LRMFD construction is not overly expensive as compared to wood frame due to the property insurance savings that are associated with masonry and concrete.
Water in masonry walls creates numerous problems: freeze/thaw fractures, cracks form, efflorescence appears, wall stains, insulation failure, material swelling, wood warp, gypsum decay, metal corrosion, paint peels, mold grows, mildew forms, and odors reek. Much thought is given to warding off wind-driven rain by using wall drainage cavities, flashing, and weep holes.
Utility Brick Bonding
This article illustrates how 1/3 bond is more economical than 1/2 bond when using utility sized brick.
Abuse Resistant Drywall ? Any School Board, which allows a construction manager to sell them on the idea of a guaranteed maximum project cost, should be required to visit previously constructed “guaranteed maximum” school projects. Then everyone could see the extent of damage and associated increases in necessary repair costs.