Tree Roots - CHANCE Foundations
The use of helical pile and beam foundations is a very effective manner of constructing your building with no disturbance tfrom tree roots near buildings. CHANCE based mini pile foundations are the ultimate tree friendly eco foundation as there is no vibration no removal of soil (as it is not a CFA pile), minimal concrete used, no cutting or damaging of existing tree roots and the piles can be placed in between existing tree roots as seen below. As the helical pile supports the ring beam foundation from a depth of ~5m below the ground your building and the existing trees can live side by side - meaning foundations near trees aren't a problem.
Foundations Near Trees Don't Need to be an Issue
We work with a number of arborologists to ensure that the CHANCE helical pile and beam foundation solution is correctly designed and installed for the ultimate tree preservation. As tree roots generally lie between 0.6 to 1m below ground level with some roots exposed on the surface we can carry out our mini pile installations using a restricted access handheld rig carried through a doorway. The installation of each pile takes as little as 30minutes for tree roots near buildings and with a new construction bracket placed on top of the helical pile the foundation is instantly ready for ring beam foundations.
222kN (Ultimate Capacity) end bearing CHANCE Helical screw pile installed to a depth of 6m terminated with pile cap ready for ring beam. a 5inch grout column surrounds the solid steel shaft which acts also as a friction pile adding additional capacity
Handheld drive head and torque arm carried through a standard doorway and installed without mechanical digger to protect tree roots near foundations.
CHANCE helical screw piles installed between tree roots to support 2 storey building, Our CHANCE Helical screw piles are the only LABC approved screw pile system in the UK meaning that local authority building control approval of helical screw piles can be guaranteed with our installations allowing your building works to continue without delay.
Tree roots and foundations are often not compatible. Attempting to build on a site where numerous trees exist can pose a series of challenges.
The fact is that trees as well as other types of vegetation have the ability to impact moisture levels a great deal, with heave/soil swelling and shrinkage being among the most prevalent risks. The end result can include foundation shifting and cracking as well as harm to entire structures. It is not just foundations near trees that have the potential for serious ramifications. Trees that stand as far as 30 meters away from a site can pull moisture from soil, producing a host of problems.
Key Issues for Tree Roots and Buildings
It is indisputable that trees are known for drawing moisture from all of the soil surrounding them and even beyond. They do this through their system of roots. When soil has moisture drawn out of it, it tends to experience shrinkage. The precise amount of shrinking that occurs will be determined by a number of factors.
Soil type matters. Soils that are comprised of clay see significantly more shrinkage than other sorts of soil. As a result, the excessive shifting of the ground has a propensity to cause foundation damage as well as to harm the structure sitting atop it. A roots foundation can be created with mini piles foundations to stop this.
Tree size is important. The eventual height of a shrub or tree as well as its type will have a large role in the amount of moisture it is able to draw from surrounding soil.
When trees are present in clay-based soil, it may be necessary to dig foundations much deeper than they normally would. Alternatively. A solution such as mini pile foundations or raft foundations can help alleviate this.
Of course, if the trees are a substantial distance away from the site, this might not matter. It should be noted that if trees are greatly reduced in size through pruning or if they are removed altogether, it is possible that some or even all of the moisture within the roots will still make its way into the soil. If clay soil is involved, this could result in soil swelling and foundation/structural damage.
We often field questions about the impact of tree roots and buildings for new structures and additions to existing ones. This often is a concern when there is an interest in keeping a significant/mature tree or one that is protected by conservation policies.
Critical considerations under such circumstances may be taken to assess whether the tree is indeed worth saving or actually embodies serious defects or dangerous traits. Tree roots and foundations are a complex issue. Fortunately, our mini piles foundations can actually be a savior here as they are easy access foundations that can provide the structure with support without the need to remove the tree.
First, it is necessary to assess the tree's root system to determine its reach in relation to foundations. Certain tree species have a high tolerance for root loss, so this should be considered as well.
Because tree root systems tend to be found just in the first 600mm to 1m of soil, beam and small bore pile foundations may suffice to keep most of the root systems of a retained specimen while also working to support the building far beneath the roots themselves. This can be done by having holes drilled into the existing soil and sinking piles into that area of ground.
After they are in place, these piles work to support beams which then will hold the building itself. Beams will sit above ground level so that there is no damage done to the root systems. Construction of this type can impact the internal floor level heights of the new structure, it should be noted. A Pile and beam foundation is a smart way of getting a building erected while keeping root disturbances to a minimum.
Mini Pile Foundations for Trees and Restricted Access
Our strategy involves arranging for the top Helix to sit no less than 2.5m below the ground. There is no movement of soil at this depth, and additional Helices will sit even deeper. While a relatively thin shaft could damage small parts of root systems, the aeration that results near tree roots and building might in fact boost tree health.
Average piles tend to be roughly 4m in length at a minimum. Therefore, if we make the assumption that the top 1.5 meters of shaft sits within soil that does shift, the skin friction can be cancelled out by the impact on the 2.5 m below. The outcome is zero net movement. Capacity of the piles will not be dependent on skin friction from the pile shaft, as the helices will bear the weight.
Structures are usually designed in such a way as to sit above ground, therefore soil movement will not impact them. A mini pile foundation system will have compression and tension capacity, making it able to resist upward pressures. Piles are driven to predetermined torques. As such, capacity is already known as opposed to traditional foundations in which capacity is only testable once they are installed.
Foundations Near Trees and Damage Due To Settling Of Concrete
It must be observed that foundation damage is not caused simply and directly by the existence of roots, though lots of people make this assumption. Rather, the roots foundation damage is actually the result of soil changes. Concrete settling is a perfect example of this. Often times, this type of settling is unattractive to the eye, but also quite dangerous.
As concrete starts to settle, it has an increased propensity for cracking and shifting. Based on how substantial this sort of movement actually is, a home's structure can be impacted a great deal. Generally speaking, if concrete has cracked only because of root presence, newer structures are unlikely to have any issues whatsoever.
If concrete has shifted due to settling problems, home foundations can see much more serious effects. Older homes in particular may suffer harm to the entire structure. Supporting beams can start to shift, walls can begin cracking and ceilings might develop unevenness. While settling of concrete is not always a major problem, it can lead to real trouble in older residences. This is why foundations near trees should ideally use a more dynamic foundation from the piling industry.
Problems With Traditional Concrete Footings Near Root Systems
Lots of reasons exist for avoiding traditional concrete footings where tree roots are prevalent. Trees can produce desiccation of surrounding soil during dry spells and trigger expansion when it rains. The end result of this is movement of the soil. When trenches are excavated, essential root areas may be severed. Concrete can harm trees as well, and will limit access to nutrients and oxygen. The example of Kew Gardens reveals that the first metre of any soil is essential to tree health. Because trees are always going to grow larger, it is necessary for the design of foundations to respond appropriately.
Other Solutions for Tree Roots near Foundations
When you are worried about the possibility of foundation damage due to tree roots, there are things that can be done to stave off this type of harm. Generally, people grow concerned once a foundation is in place and neighboring trees have long been in existence.
A possible solution is to construct a root barrier. In doing this, it might be necessary to dig completely down to the foundation of the structure. Roots can be cut near the foundation itself while the digging is being done. This can be an arduous undertaking, but it provides peace of mind and relief from worrying about root expansion and weather conditions.
Should you desire to plant a tree in the area of your home, you may be able to prevent root risks by choosing a species that is slow-growing and features weaker rooting inclinations. Avoid silver maples, willows and elms that are known for their extremely deep rooting tendencies. Opt for sugar maples or oak trees that demonstrate slower rates of growth.
Alternate preventative strategies for keeping root damage at bay include redesigning your garden space so that trees are in different places than originally planned. Think hard about your yard's actual size before doing any planing. Many believe that tree roots will spread as broadly as the height of the tree itself, but this is not accurate. Trees can actually form root systems that are 2-3 times their true height.
Should you lack sufficient space to allow for these types of roots, reconsider your tree species or select a different type of landscaping scheme. If a new structure is in the offing, there are many things that can be done to stop root damage from emerging.
If root damage has you worried, the answer is not to begin chopping down all of the surrounding trees. In many cases, this is not needed, and alternative strategies such as mini piles foundations, can accomplished the desired outcome.
The bottom line is that roots are not the dire threat that many believe. By conducting an assessment of the type of soil present and finding the best foundations for near trees, it is possible to avoid unnecessary elimination of trees and still provide structural protection.
Both pile and beam foundations and mini screw piles foundations can be the perfect solution for tree roots and foundations and the issues caused.
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