Owner and Operator
Eric’s career in home building started some 25 years ago while living in California. He had opportunities to work on luxury homes in Balboa, high-rises in L.A. and cliff-hanger houses in Malibu. It was in 1997, after working with the Union on Honolulu’s Inter-Island Terminal and under private contractors for several years, that he became a licensed General Contractor and established Levora Builders, doing primarily home building.
Micropile technology first came to his attention during a major remodel of a Waialae Iki home. It seemed the perfect solution for so many 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 methods commonly used, and was perfect in difficult access situations such as underneath structures or even inside occupied dwellings with the typical 8’ ceiling. 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 he decided to try it on his own residence.
Eric works closely with an engineer to determine how best to approach each job: How many Micropiles are needed & at what intervals, how to handle sub-terranian voids & water run-off, whether a retaining wall is salvageable with micropiles and buttresses, etc… This, he has determined, is the most low-impact and cost effective method available today, and so, Anchor Systems Hawaii has gone from home building to foundation saving!
Hawaii Home and Remodeling Interview with Eric Levora
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 soil away 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 wrecks 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.
What are Weep Holes? Should these be installed as well?
Weep holes are drainage holes which allow water that accumulates behind retaining walls to escape rather than sitting & soaking causing soil to expand, etc. Another way to accomplish this is to excavate behind the wall, install gravel, set perforated pipe along the length of it running to daylight, back-filling with more gravel, geo-cloth then soil & grass or landscaping..
Why do failing retaining walls seem to be an ongoing issue here in Hawaii?
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 up-slope neighbor can influence how rainwater sheds off their property and into yours. Be aware, and make adjustments as needed.
Can your company repair walls? How do you know when to repair or replace?
Yes, we pride ourselves in aesthetically pleasing wall repair. The decision to repair vs. replace usually comes down to comparing 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 for repair 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, and of course cooperation between neighbors is a lovely thing in those situations as well. We are adept at helping the permit process along and writing the letters needed to allow for, say, sub-terranean encroachment of Micropiles (where the Micropile crosses the property line sub-grade) – which would qualify as encroachment, even though it can’t be seen.
Describe some of those fixes to repair a wall.
The material the wall is made of, it’s condition, the depth/girth of the footing, accessibility, aesthetic requirements, and owner’s budget all play into the ultimate remedy. Whatever the plan, we employ Grout-injection Micropiles to hold structures in place. We generally use 30/11 hollow steel bars in residential applications. That’s 30mm outside diameter, 11mm inside diameter, and ribbed on the outside like a screw. The bars come in 10’ lengths which we can “couple” together to reach required depths. The Micropile is fitted with a carbide bit with pukas in it, that can be drilled through rock. We load the bar with bit into one of a range of rock drills we have, and drill vertically or at angles, as the plan requires, all the while pumping high pressure grout slurry through it and into the surrounding material, filling voids and fissures as we go. We can ‘feel’ resistance as we advance the piles into the ground and will generally drill to 20’ or into rock, whichever comes first. Micropiles are spaced no less than 8’ apart, cut several inches above grade or face of wall, finished with steel bearing plates & nuts and tied together with rebar creating a system of anchors to keep the wall from moving further. We then form and pour concrete, or in some cases apply ShotCrete to encase the steel, sometimes carving and staining it to look like natural lava rock.
Let’s say a moss-rock retaining wall at property line has cracked and offset in three places, and if left for another wet season would likely wind up in the down-slope neighbor’s Jaccuzzi. (This was an actual job.) We got the neighbors agreement to allow Micropiles to be drilled and Buttresses constructed on their side of the property line. We excavated down to the bottom of the footing in three places 8’ apart along the base of the wall and drilled a vertical Micropile in each puka. Straight up the wall from each of those we drilled an angled Micropile, through the wall back into the hillside. We then created a rebar cage incorporating the top of the vertical Micropile and the top of the angled Micropile in three places. Each was formed and poured with concrete creating Buttresses that looked quite architectural, almost intentional. CMU or “cinder block” retaining walls should be built with reinforcing steel and cells should be grouted, but often aren’t. We’d first assess drainage issues and pull cap pieces off to see whether cells need filling.. Let’s say a CMU wall has cracks between blocks kind of stair-stepping their way here and there, looking like it’s pooching out a bit. We can ‘stich’ the cracks together by drilling holes on either side of them and inserting rebar stirrups secured with Epoxy. We would excavate to reveal the footing and drill vertical Micropiles along its base, inserting a rebar cage to incorporate the top of each one, bonding the whole thing to the wall footing and pouring concrete to encase the steel. We’d also drill Anchors through the wall, back into the hillside at 8’ intervals, above the lower ones and tie steel to face the entire wall. We’d then apply ShotCrete to cover the whole wall and as it starts to cure, carve it to look like a natural lava flow. Days later we’d return to stain the raw ShotCrete to a natural looking mottled brown.
What’s the worst thing for Retaining walls? Is it rain? Wind? Sun?
Yes, yes and yes. Add to that Banyan roots, unchecked leaking irrigation, a rotted out tree stump creating a highway for water to run through and undermine the integrity of a wall.. Movement, exposing reinforcing steel to oxygen and worse yet, salt..
Any other messages you’d like to be sure we get out in this piece?
Primarily, be observant. Call us for an assessment if there is a concern. Install gutters if you haven’t already. Route rainwater away from walls and all improvements. It’s much more fun to spend on remodel projects – things you can see and enjoy!