Pic attached

Depends on council in many cases.

Personally I'd be considering to remove the tree completely or even better design around them.

You'll upset the tree whatever you do. Sometimes they recover well sometimes they don't.

Sounds expensive. Did your designer do any type of site analysis before commencing the design? This issue should have been flagged by your designer at an early stage. Perhaps your new extension could have been designed to avoid this conflict. I think you need to chat to neighbours and council. If you were my neighbour I probably wouldn't want to cut down my significant trees to accommodate your extension.

Best of luck,

Dr Retro

of Dr Retro House Calls

If they are Gums they won't be missed in a built up area, they can be extremely messy and very dangerous

100% agree with Retro - the first thing you (should) do as a designer is survey and analyse the site for constraints. Existing significant trees, whether your own or actually more importantly neighbouring trees, should be negotiated and managed as a constrain not dissimilar to a planning setback constraint or similar. You may be able to negotiate the dig or foundation design with $$$ but potentially it may be proven not financial viable or worth it.

Established trees can be considered very valuable to a property landscaping, gums or whatever species, in that they create a particular natural outlook.

That said I think technically the law is that you have the right to remove branches or roots of a neighbouring tree on your boundary. BUT depending upon your local planning policy the trees may be protected by vegetation/design overlay or significant tree objectives.

I'd be seeking advice beyond just your building designer - ie council/building surveyor/legal etc

Gums were part of the development, planning, landscaping process from the 70-80's, which have been shown to have been a bad choice in residential areas and your average block, no one considered their size and how unstable they can be, dropping large limbs and being uprooted in storms. Sydneys North Shore is testament to that.

Our current house is from that period and the obligatory Gums were planted one of which when it was very large came down onto the roof of the house causing major damage, the others were promptly removed.

I'am all for preserving trees but the right ones in the right situation, I have my fingers crossed that these trees are the right type for this position, good luck

Thanks for all the comments

We have been considering the trees the whole way through the design process and moved our pool recognising that it would be unlikely to get through near the trees...

The arborist and designer both think our plans are realistic and the house is built no closer than what the neighbours have done. The garage is closer but canary palms can usually be transplanted so unlikely to be too disruptive to its root system.

We don’t expect the neighbours to remove the trees (one is a ghost maple and the other two are canary palms that are only 1.5m apart) although that would be amazing as I hate them being so close.

I am more curious to understand anyone else’s experience and the logistics of being tree sensitive during the building process and the costs incurred. Is it normal for the arborist to be onsite for demo and excavation? Are we better to dig a trench prior to the build to go in with our eyes wide open rather than wait and see approach....

The problem with trees is they create movement in the soil in comparison to areas of the slab where there are no trees. This can be resolved with piers. Then there are species of trees that have invasive roots. In this circumstance you will need to install a root barrier.

The Palms can be moved and even sold onto a nursery, if access is difficult they would need to use a Crane but all included with sale.

It would be amazing if they could even transplant one of their palms however I’m not holding my breath!

The TPI - tree protection zone is in place for a reason. The TPI aims to protect existing trees at all costs.
Trees are valuable in our suburbs not only for aesthetics, but also the positive environmental impacts engendered.
Do you know what the trees are? If they're short-lived species, negotiation with neighbours could be helpful.

I have just read that they are Palms. Most palms have very contained root systems - that's why they transplant better than some plants.
A palm is not a tree. But they can still get big, and often have a very long life.
I don't believe that you can expect your neighbours to remove them for your build. You will need to work with them in situ.