Trees and Concrete

By Adrianne Bauer

This article fist appeared in The Communicator, Spring 2023 Edition. 

There is no product more commonly used than concrete.

We can’t exist without trees providing this little thing called oxygen.

Therefore, trees and concrete exist in the same environment – sort of like cats and dogs. Trees continuously grow both up and out as they become older, changing their footprint. Concrete is a finite object that is most often damaged by trees. So, how do we make it all work?

DEVELOPERS – HOW COULD THEY DO THIS TO US?

During development, landscape architects and developers put together their brilliant plan to create a beautiful community, knowing that eventually there will be issues. Most developers/landscape architects install fast-growing trees in order for the property to sell quickly. Unfortunately for us, these fast-growing trees with fast-growing root systems create future issues that we find in almost all communities.

Once these trees reach a certain age, they use up the available root space and begin to expand their structural roots. Unfortunately, this happens in all areas all at the same time. I liken trees to bananas. When you go to the store and buy your bananas they are all perfectly the same ripeness. In what seems like three minutes later, they all seem to go brown at the same time. Trees are like that. All the ‘milestones’, growth, and issues seem to arise at the same time.

Depending on the types of trees, these issues will continue as long as the trees remain within the community. Homeowners are often shocked when they are left to pick up the pieces – and the costs. To me, this is an avoidable issue that should be forecasted and planned to minimize the pain.

HOW DO YOU STOP A TREE FROM DOING DAMAGE?

The answer is – you don’t. Let’s get one thing straight, there are no bad trees, just bad locations, and some species of trees are planted in the wrong location. Don’t despair; there are solutions if you are strategic. The process should be a long-term strategic collaboration that will require cont ributors to work together for a common goal. Homeowners, board members, HOA management, arborist/tree company, and cities must buy in (in some cases). This can require some tree removal and rerouting of existing paths/sidewalks to give the trees more room. It will take a long-term commitment and strategic decision-making that will ultimately make the property safe and beautiful.

TREE ROOTS AND CONCRETE – A SUPERHIGHWAY!

Concrete and trees coexist in our world begrudgingly, but we need them both. What people don’t realize is that theirs is an organic environment that continues to change as the property’s trees continue to grow. Removing all the trees is not a viable option (no city will allow that, nor will the homeowners). Eliminating the concrete walkways won’t work either, as homeowners, the disabled, guests, and all need paths to navigate the community.

As the tree grows, its structural roots grow with it. Tree roots are impressive, interconnected systems that support the tree’s overall height and width. The bigger the tree, the wider and deeper the root systems. If concrete is within the root zone of a tree (under the canopy), there’s a high probability of lifted and/or damaged concrete. Paths that once were unaffected when the tree was planted become damaged once the tree’s growth increases. Communities must have forward-thinking solutions regarding preserving their trees and hardscape and ensuring that all who use those sidewalks remain safe.

BENEATH THE SURFACE OF CONCRETE AND SOIL

What is beneath both soil and concrete impacts everything above the soil. During our multi-year droughts, our soil has continued to compress. Compressed soil is much like a brownie that you’ve left in the oven that has continued to cook.

CONCRETE BUSTERS

Concrete is most often damaged by tree roots growing beneath it. There is a base layer of rock, which lends structural support to the concrete. Tree roots find it easier to go through the base rock rather than the highly dense grass/soil. Most of our Northern California soil is clay based and it has been steadily condensing from years of drought and loss of groundwater, leading to soil compression.

STRATEGIES TO KEEP YOUR CONCRETE IN GOOD CONDITION

• Come up with a strategic plan of the goals for your community; for example, a safe environment for homeowners, pedestrians, and visitors who come to your HOA community.
• Budget concrete work EVERY YEAR.
• Grind concrete every year.
• Grind each piece no more than three times. After it’s ground too much, concrete begins to break off, leaving holes. Holes are as much of an issue as the lifted concrete.
• Just because something can be ground ask yourself if it should be. Pools? Overly ground areas?
• Companies that only grind will tell you to grind. At some point, the cost doesn’t make sense to grind something that should be removed.
• Americans with Disabilities Act (ADA) should be considered in all areas. ADA is applicable on city sidewalks. ADA is a requirement of all sidewalks.
• Remove (not grind) anything that is lifted more than 1". If you grind anything that is lifted more than 1" the ADA grade and slope is compromised (more than 5% front to back and 2% side to side).
• The longer you wait to remove concrete, the more you will have to remove to meet the ADA slope and grade.
• Never grind curbs. Curbs are expensive given the volume of concrete within them. Curbs are comprised of 6" of concrete above the ground, and 4" below the surface to provide stabilization to the curb. When adjacent concrete is sinking and/or lifted above the curb, it usually is a result of soil compression, water, and/or tree roots. Once the curb is ground, eventually both the curb and the adjacent concrete will need to be replaced.
• Small pieces in driveways usually break as there is not enough concrete to disperse the weight of vehicles. That may not be the most cost-effective method of dealing with a broken driveway.
• Concrete professionals and arborists will not agree. Each will have wildly different opinions on what should or should not be done. Find someone you trust and craft solutions together.
• Whenever possible, try to share what you have to spend. Every property I’ve ever been to needs more concrete work than they have $$. Partner with your vendors to craft a clear and consistent direction.
• Technically, every hazard should be addressed; however, this is most likely unrealistic. Help your vendors narrow down the true priorities. Create priorities that remain consistent and move forward with that plan. For example, mailrooms, pools, etc. are always a first priority based on the volume of people who use them.
• Never grind a pool deck. Ground concrete becomes slippery. Slippery concrete and water = a slip and slide!
• If your concrete is 25 - 40 years old, it’s considered elderly. Start to increase your budget in accordance with your tree size. Older properties = bigger trees. Bigger trees = more $$.
• Make sure your vendors are providing forecasting for your next year’s budget that continues with the same agreed-upon plan.
• Downspouts are the second most common reason for sinking and lifted concrete. Make sure downspouts do not deposit onto concrete.

RULES FOR CONCRETE / ASPHALT VENDORS TO FOLLOW

• Have new concrete ‘dowelled’ into the existing (adjacent) pieces. Metal rebar provides structural stability and tethers concrete together. It does cost more to use the rebar to connect pieces together, but it results in stronger concrete.
• Always ensure that any time concrete work is following California State law, requiring contractors, to mark all removals and utilize 811/USA Dig prior to starting the work. The State of California also requires that all people working on projects that are below ground must call in this work to 811/USA Dig to prevent underground damage.
• Ensure that all contracts for new concrete stipulates that newly installed concrete has no trip hazards (a trip hazard is 1/4"). All transitions should be smooth with no raised concrete where existing and new concrete meet.
• Asphalt hates water. Many times, several layers on asphalt (overlay) is added. This oftentimes results in compromised drainage, which leaves pooling water. Pooling water breaks down the asphalt and shortens its lifespan.
• Ensure that all asphalt vendors understand that all transitions between concrete and asphalt must be even with no trip hazard. Build this into your contracts!

CITY SIDEWALK TIPS

All city sidewalks require encroachment permits. Make sure your vendor provides you with a copy of the permit.

• Fines are administered when city sidewalks are not completed in a timely manner. Don’t wait – it won’t go away.
• Even if the city takes care of the sidewalks (Sunnyvale, Pleasanton, to name a few), it is advised that your vendor provides a copy of the locations to the city. The property is still liable if someone trips and falls even if the city takes care of it.
• City sidewalks (in almost every California city) are the responsibility of the homeowner that is adjacent to that concrete, in accordance with California State and Highway Code 5610.
• Work with the city on crafting strategic plans for addressing damaged city sidewalks. Ask if they’ll consider bulb cuts, removing and replacing the tree, etc.
• Lifted sidewalks at the curb still count as damaged.

MARKING CONCRETE – NEVER ALLOW IT

Never allow any vendor to mark a hazard for estimate purposes. It connotes that there is a hazard and the property is aware of it.

LAWSUITS

• Trip and fall lawsuits follow the economic environment and they are increasing. As our economic environment becomes more challenging, lawsuits become more frequent. There are a lot of figures out there, but each lawsuit is based on the injuries.
• If the owners of the property have consistent documentation of concrete repairs and corrections, this shows that the community has consistently maintained the adjacent city sidewalks. Trust me - it helps!

Adrianne Bauer is a strategic partner, providing strategic approaches and out-of-the-box solutions to aid her clients. She has a unique background, with many years of experience in a variety of fields. An ISA Certified Arborist and the regional manager of Trip Hazard, Bauer uses her tree knowledge to implement long-term solutions.