Solid Solutions: Expert tips on micropile technology and retaining walls

Eric Levora of Anchor Systems Hawaii shares his expertise.

Eric Levora’s career in homebuilding started some 25 years ago. Micropile technology first came to his attention during a major remodel of a Waialae Iki home. It seemed the perfect solution for so many of the foundation problems he had come across during his career. It required no excavation, took less space, had less of an impact on the grounds than other commonly used methods, and was perfect in difficult-to-access places such as underneath structures or even inside occupied dwellings with typical 8-foot ceilings.

Where can micropile technology be used?

Due to ultra-low soil displacement, it can be used adjacent to pools without cracking plaster or tile. The system worked beautifully on the Waialae Iki home, so Levora decided to try it on his own residence. He works closely with an engineer to determine how best to approach each job: how many micropiles are needed and at what intervals, how to handle subterranean voids and water runoff, whether a retaining wall is salvageable with micropiles and buttresses, etc. This, he has determined, is the most low-impact, cost-effective method available today to shore up walls. With that determination, Anchor Systems Hawaii has gone from homebuilding to foundation saving!

How often should you inspect your retaining walls?

Seasonally. When it comes to movement, the culprit is usually water in combination with expansive soil and good ol’ gravity. Water can, of course, wash away soil and undermine retaining walls, but it’s most often changes in the soils’ moisture content behind and/or below that will cause the swelling and shrinking that wreaks havoc on them. Check your walls as the weather changes from dry to wet, and wet to dry.

Why is that important?

Because you want to catch clues of movement earlier rather than later. Be sure not to allow vegetation to obscure your view. If you notice a crack and want to monitor it for further movement, an easy way is to paint a line across it, take a picture, and make note of recent weather conditions.  Go back regularly to check and document whether the line is still straight, or has offset. This really helps in determining the level of priority to assign the issue.

What should you look for during this inspection?

Look for cracks, bowing, and whether the wall is plumb. Look to see if tree roots are infiltrating cracks or weep holes and get them gone. Also, generally look at how rainwater moves across your property. So often, we see situations where if rain gutters had been installed, water would have been directed away from foundations and walls and costly problems could have been avoided.

Why do failing retaining walls seem to be an ongoing issue in Hawaii?

It’s our geology, topography and tropical climate. Our volcanic islands are eroding. We’ve got a lot of clay, which is expansive. Hydrostatic pressure is an amazing force. Constant humidity would lend to stability but we have wet and dry cycles. Being that our ridges and valley walls are favorite places to build, we really need to plan how to move water across our properties without causing problems. Changes made by an upslope neighbor can influence how rainwater sheds off their property and into yours. Be aware, and make adjustments as needed.

How do you know when to repair or replace?

The decision to repair vs. replace usually comes down to the cost of each. Sometimes the deciding factor is the property line in relation to the wall, and the relationship with the adjacent neighbor. Permission to gain access through a neighbor’s property can make a huge difference in price as well as the safety of our crew.  Sometimes an encroachment agreement makes the most sense. We are adept at helping the permit process along and writing the letters needed to allow for, say, subterranean encroachment of micropiles (where the micropile crosses the property line subgrade) – which would qualify as encroachment, even though it can’t be seen.

Any last words?

Be observant. Watch how water moves through your property and mitigate as needed.  If you find you need help, we pride ourselves in cost-effective and aesthetic solutions to wall and foundation issues of all sorts

Anchor Systems Hawaii, Inc. | Base Yard: 907 Kalanianaole Hwy, Kailua HI, 96734
Office: 44-011 Aina Moi Place, Kaneohe Hi. 96744 | (808) 330-9002  | Eric@AnchorSystemsHawaii.com