Houses and Roots

One end of my house is built on a massive Moreton Bay fig root which runs horizontally under a corner of the house. As the tree has grown over the last hundred years to be truly massive, clearly so has the root over which the house was built 60 or so years ago. So with long dry spells or unusually rainy seasons the whole corner of the brick house lifts and drops, and this shows most clearly in the front door which is right on that spot. Rebuilding the corner of the house is not an option and killing the root and/or the tree may not be either. Difficult … but it is surely not a small job! Any advice much appreciated.


Hi @ghsouvigny, since your question is not about finding services although is about getting quotes I created a new topic for your query. I hope you get some good advice even if just an expected - get a few pros to offer their solutions.

But from the previous posts it seems the magnitude of work being clear could be important to attract inspections and estimates.

A problem bring when companies are busy with east jobs, do they want hard ones?


This is a very difficult problem. Big old trees put pressure on your foundations from their roots directly but also indirectly. They soak up a large amount of water and depending on your soil this can have a great effect on the house if it is nearby. The roots of a big tree travel out a long way. If the soil has a high clay content then the tree can exacerbate the swelling and shrinking of the soil as rainfall changes. When in dry times the tree extracts water from the soil as well as evaporation and so, if it is reactive, the soil shrinks even faster.

If you kill the tree everything changes. It stops taking water and eventually the roots decay leaving hollows. So getting rid of it is something to take much thought about.

The obvious thing is to not have big trees near the house but there are times when the previous owner, or several back, should have taken that decision. When that doesn’t happen it leaves you with a big problem. This may lead to where you are wondering if you ought to have bought the house.

I don’t have an answer but can only say get some expert advice and be prepared to do harm minimisation as there may be no affordable cure. The size and place of the tree, the type of soil and many other questions will matter.

This leads me to a broader observation that big trees near houses can look lovely and provide shade but they also cause this kind of problem as well as drop branches - or the whole tree. Each time there is a big storm we see footage on TV of houses in leafy suburbs and sad advice given as part of the house is under a few tons of wood while the emergency services stand shaking their heads. “If little Tommy had been in bed and not got up to have a pee he would be underneath”.

I live out in the country and have room to do whatever I like. Visitors ask me why I don’t have trees near the house. My answer is I want to sleep well during storms and not worry about my foundations, and I don’t want my heirs to have those problems either.


Have you considered trenching out from the house footings to cut all roots and then installing a root barrier. This will stop roots continuing to grow under the house.

It may be worth getting engineering/geotechnical advice as it sounds like the root could be, in some ways, supporting the corner of the house and cutting the root might result in soil/house subsidence in the long term if the root system is extensive. If the root system is supporting the house corner, things like underpinning may be required.


It may be best to first consider the tree, and whether it is possible to live with it in some way. A professional tree arborist will be able to advise if there are options for managing the tree. These may include root surgery and barriers, if at all practical. Stability of the tree will be important. Being a fig it’s roots will work along any barrier and ultimately try to go around it.

Ask at your local nurseries for recommendations if you don’t have any knowledge on who to contact. Your local council environmental staff may also be prepared to advise who they use for such services.

On what might be the outcome for the corner of the house.
If the fig is removed or the invading roots cut free and treated, they will eventually decay and leave a void, as @syncretic and @phb have commented. How the foundations of that corner of the home will settle, IE how quickly and how far, will be difficult to predict. Remedial work to correct and stabilise in the short term will be an added expense. Leaving works until any settlement occurs may be less expensive initially. If left, there may be minimal settlement, a return to near original or uneven movement. All have some potential to cause cracking of the brickwork, and structural issues. You may be lucky with the soil type, foundation design and future movement being minimal.

It’s open for the advice of another experienced professional. It’s likely they will recommend an excavation to establish the extent of disturbance and footing conditions, prior to any further remedy to ensure the footings remain stable. There are specialist businesses who design footings and foundations. They will inspect and provide a recommendation/report on what is required. Search the internet on those terms for your area and or contacting local architects for advice on who they may work with. If you know a building professional who is reliable or a personal contact they may be able to offer some options.

Alternately there are also businesses which specialise in footing repair - underpinning being one common remedy. They will inspect and quote, but are more likely to advise more extensive work out of uncertainty to be sure.


All the advice so far has been good. Getting professional advice and quotes are the way to go. Is your house on stumps/poles or concrete slab? Just be mindful that a 60 year old on-ground slab house did not use the same building techniques we have today. From what you have said, I would get a soil test first. If your house moves, thats clay expanding and contracting with moisture. 60 year old concrete would have most likely been mixed on-site. Depending how tired the worker was putting the right amount of cement to sand and gravel at the time, will allow cracks to form over time where tree roots can enter. Once a root expands and cracks concrete, it does not contract.