Bowing Or Cracking Masonry Block Walls

Bowing Or Cracking Masonry Block Walls

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MASONRY BLOCK GROUTING / BOWED WALL REPAIR:
The Problem"

Masonry block foundation walls bow and crack due to exterior lateral soil pressures. These pressures or forces are caused by a naturally occurring active soil state when a soil mass is allowed to relax or move outward to the point of reaching the limiting strength of the soil. Winter freeze cycles, heavy rainfall, concrete driveways and stoops in close proximity to a foundation wall are all contributing factors to this force. Masonry foundations have difficulty resisting these pressures over an extended period of time due to low shear and tensile strengths comparatively to a solid concrete wall. Once the lateral forces cause cracking, a loss of structural integrity to the wall occurs. Shear and tensile strengths are greatly diminished and responsible for resisting lateral forces. Once a masonry wall is compromised in this way, continuing forces on the wall can rapidly (swiftly) cause further damage.

Over the years, numerous repair methods for masonry foundation repair have been developed and performed "" all with varying results due to contractor inexperience or poorly conceived corrective methods, or those that offer marginal benefits. Many of the methods focus on addressing water infiltration, a symptom of the bowing and cracking walls. Although these methods do inhibit and divert water infiltration, they do not address the structural damage to the wall, as well as the subsequent damage caused by continuing structural compromise. Once the wall has suffered the consequential damage, it continues be a detriment to the structure, unable to perform to its original design capacity. Some techniques such as exterior dead men, interior buttresses, and tie backs are focused on resisting lateral forces, but are limited to their area of influence, the area of contact, and its close proximity. However, each has its consequences of aesthetics, inconvenience and/or installation issues. For example, dead men require exterior trench excavation and interior buttresses require large open space without obstructions. Tie backs require property lines that are set back enough to allow for work without inhibiting property line egress of neighbors, as well as the ever-present underground utilities and tree root systems that exist in and around the home.

Recently, there has been some use of carbon fiber strip installation to provide structural resistance to lateral forces. The difficulty lies in the appropriate anchoring of the top and bottom masonry block courses. The floor slab and upper floor joists anchor to these courses of block as well. Due to the subsequent minimal surface available on these blocks, painted surfaces, conduits, plumbing, and numerous other wall obstructions, it is often very difficult to install the strips to the manufacturers recommended specifications, thus offering inferior results.

In short, all methods mentioned above address the symptoms, and are limited to localized resistance to bowing and cracking masonry foundation walls. The various methods referred to originated as alternatives to complete removal and replacement of the foundation wall with new masonry or formed and poured concrete. However, these methods and/or replacement create the need for additional work including but not limited to shoring the home, excavation, driveway or porch removal, landscaping, interior and exterior utility issues, wall debris disposal, window replacement, building permits, and so on. The one notion all can agree on is that although expensive, total replacement of the wall, either with new masonry or poured concrete, is the very best solution to the problem.

The Solution"

With total replacement as our best answer to the problem of bowed and cracked masonry foundation walls, let us turn toward yet another solution far less expensive than replacement. Masonry Block Grouting offers a process that responds directly to the lack of effective shear and tensile strengths lost due to bowing masonry walls. It is a method of repair that is cost effective, and "fills the void" so to speak, on attacking the cause of the problem with minimal disruption and project duration.

To stabilize and strengthen a block foundation wall, it is necessary to restore the foundation"s shear and tensile qualities. This is accomplished by placing vertical rebar"s in the wall and pumping a high-strength cementitious grout into the hollow cells of the masonry wall encapsulating the rebar"" filling the voids and hair-line cracks in the mortar joints. The process can turn a slightly bowed, structurally marginal wall into a uniformly solid concrete wall. The procedure resists further bowing and cracking, eliminates water infiltration, inhibits susceptibility to mold, and even insulates the wall.

The Process"

Small holes - one inch in diameter, are drilled into the upper block course to access the cavities from the exterior. When exterior obstructions exist, such as a porch or other structures, the holes can be drilled from the interior on an as needed basis. The high-strength grout is then pumped through a hose from a mix-on-site portable batch plant "" completely filling the wall solid. The pumping equipment is small, portable, and can be located street-side with no excavation necessary. The process is clean, fast, and far less expensive than replacement, and ultimately solves the problem long-term.

Masonry Grouting Advantages

"The grout material can be pumped from two hundred feet away, therefore reducing any inconveniences immediate to the work area and landscaping.
" The process provides a one-two punch in eliminating water infiltration
"Gives off no odorous intrusions or creates dust
"No disruption to household activities
"No excavation
"Lower costs than total replacement
"Creates a solid, uniform wall
"Seals cracks, bonding all blocks together
"90% of repairs can be performed from the exterior

About the Author:
http://www.lincolnllc.com/



Article Originally Published On: http://www.articlesnatch.com


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