 |
 |
|||
|
|
||||
 |
 |
|
|
|
|||||||||||
|
Home >> Articles >> More on wall problems
 From The Best Times - July 2003By Don Carter, Structural Engineer “Home Front” ran a recent piece about “ugly basement walls” — and based on the level of inquiries and reprints, this was a topic of substantial interest. The most frequently asked questions concerned methods of repair when wall damage exceeded our recommended limits. In this and future issues, we will describe the most commonly accepted wall repair systems. Problem: leaning walls Basement walls that rotate inward do so because earth and water combine to push against them at a rate that exceeds their design capacity. When this happens, the wall typically splits, then leaks, and eventually disconnects from the house. These flaws never get better on their own, and once disconnection happens, the wall is unstable and will move even more. There are two pretty good fixes for this condition, described here in order of preference:  Helical tieback. This is a modern-day version of what your grandfather may have called a “dead man.” It works by anchoring the wall into the yard, much like a big lagbolt spun into the dirt.Installation starts with a 1-inch hole drilled through the basement wall, into which a 3/4-inch rod is inserted. A screw-type end piece (helix) then gets attached to the outside rod end. The whole assembly is then turned into the earth, much like turning a screw into wood. When force required to turn the rod reaches a predetermined number, the helix has twice as much holding power as the force pushing against the wall. I like this system for several reasons. First, the installer is able to validate capacity during installation. Second, it is often possible to bring a crooked wall progressively back into alignment by periodically tightening the plate nut. Finally, with only a flat plate against the inside wall, repairs are not overly obvious and it is easy to finish the basement walls for living space. I-beam braces. For about half the cost of helical tiebacks, steel I-beam braces mounted against a leaning wall’s inside face will stop movement. The beam is potted into the basement floor for bottom support and bolted to floor joists for top support. Beams are shimmed tightly against the wall so it can’t move without displacing the entire sub-floor—which it won’t do. Beam braces are something homeowners with reasonable skill can do themselves, but several companies install them at competitive prices, often for slightly more than you would pay just for materials. Beam braces are unattractive and call attention to the problem, so there is a potential for buyers to wrongly assume that the beams represent an unsafe or protracted condition. Regardless of how you stabilize a leaning wall, when all of the movement is arrested, cracks need to be pressure-injected with two-part urethane to keep bugs and water out and major breaks need to be rejoined with a carbon fiber overlay. Don Carter is a licensed structural engineer and managing general partner of Foundation Engineering Specialists LLC, a company specializing in residential design and assessments.  |
|
 |
||
|
|
||
 |
||
 |
||
5525 Raytown Road • Raytown, MO 64133 • 816.358.3300 • Toll-free: 800.373.9800 Visit Pro Concrete Design for the best concrete engraving, concrete staining & concrete polishing. Web site design by Big Ape Studios. Concrete Resurfacing |
