We had a bid from Tom the Contractor to install four root barriers to stop the underground tentacles of nearby trees from sucking moisture out from under our concrete slab foundation. We accepted his proposal and are tentatively scheduled to have the work done next week.
His crew will also dig out a row of Nellie R. Stevens holly bushes that grow right next to the house foundation along the west side.
You may recall that whether the hollies should be removed or not is a point of disagreement between the Mike the Engineer who inspected the foundation and this contractor. (more…)
The inspection I had done on my concrete foundation calls for one root barrier to go between the slab and one live oak tree that is 12 feet from a corner of the home. One of the contractors I called for bids thinks I should have four root barriers. Two of them for other trees on my lot and one to protect the foundation from a neighbor’s tree.
One of the trees is in the front yard, is pretty big, and frankly I’m surprised that Mike The Engineer who did the inspection wasn’t concerned about it. It is a maple, and he doesn’t think the roots of that species of tree are all that invasive. Tom The Contractor thinks they are.
Another point of disagreement is the row of hollies along the west side of the house. They can get huge. I have to trim them back at least twice a year. For reasons I can’t recall but were most likely based on laziness, I let them go for a couple years without a “haircut.” They grew a good twelve feet tall and were peeking over the roof line before I delivered their next whacking. Mike The Engineer said if they were red-tipped phontinias they would have to go, but hollies are ok. Tom The Contractor says both types of shrubs are bad for foundations because they can draw enough moisture from under the slab to contribute to settling.
The biggest point of disagreement between these two professionals is whether or not I need underpinning, or piers, installed. Tom The Contractor, who sells and installs piers, doesn’t think I need them. He thinks by cutting all roots headed under the slab, installing four root barriers, removing the row of hollies next to the house and installing a good quality soaker hose system he can get enough water back into the clay soils under the slab to reverse the settling and get some lift.
Mike The Engineer also thinks the foundation will benefit from a root barrier and soaker hoses and suggests waiting a year after installing those items to see if there won’t be some lift. But his report calls for piers after that. 21 of them. Many U.S. dollars.
So I’ve had two experienced professionals come out and look at the foundation and have two different opinions on what to do, both based on “I’ve been doing this for many moons and I know what’s best.”
I emailed the engineer’s inspection report to another foundation repair contractor for a bid on the root barrier a week ago, but haven’t heard back. I guess they are busy. Stay tuned.
The structural engineer who inspected my foundation Monday is recommending a root barrier be installed in a back corner of the yard to keep roots from a nearby live oak tree away from my concrete slab.
They are also called root walls and root caps. The idea is to cut any roots that are reaching under the foundation, then put something in the ground between the tree and the slab to keep the roots from returning.
The hope is that by keeping the tree from drawing moisture from under the slab, the clay soil will re-hydrate and give the foundation in the back of the house some lift. Not much, but some. The tree is 12 feet from the corner of the foundation. (more…)
You hear a lot about tree roots causing concrete foundation problems for houses that sit on expansive clay soils and may be wondering how that can be.
In my travels around the Internet I’ve learned the trouble is two-fold. Large trees can suck huge amounts of water from the soil. If thirsty roots get under your slab, they can reduce the moisture content of the soil and cause settling.
Tree roots under the foundation can also worm their way into the plumbing causing leaks and again changing the condition of the soil under the foundation. Heaving of the slab can occur. (more…)
These are photos of oak tree vs. sidewalks in my neighborhood.
In some cases, the tree roots are winning. In other stretches of the sidewalks you can see slumping as the soil underneath erodes or settles.
The question is can tree roots do damage like this to the concrete slab foundation of your house? There seems to be a debate. (more…)