Removing neighbor's tree branches over my rental property?

Rehabbing, Fix and Flip, Rental Properties
1

Here’s a real dilemma…the only way to improve one of my small resort properties is to raise the roof and put on an addition over the first floor. Unfortunately these are typical resort properties (a lot of house for the size of the lots.) In this case, the neighbor’s large older tree has branches where
our two new bedrooms will be. Can I ask the neighbor to remove branches? They look to be substantial in size. What if that impacts the tree’s health? I am not sure what to do.

I always intended to do this at some point, but I’m just now thinking seriously about it since it would really help in expanding a very small house. Zoning should not be an issue since there are other two story homes (older and newer) on the same street.

I am in the formative stages and have not located an architect or determined if I can afford this. How costly is it to raise a roof and add a layer? This is a property that I hope to hang on to for a very long time and this will greatly improve on the rent I can ask for. The location is good so the improvement is warranted for the long term.

2 
 I would first contact the neighbor and ask them if you could remove the branches. Offer to have a reputable tree company, that is a trained aborist, or certified arborist do the work.
3

Yes, I would definitely talk to them about this - we have a pretty good relationship. The tree roots are also wreaking havoc under our stone patio. I’m a fan of trees so I think an arborist is in order. This tree just grows like crazy. I worry that this is perhaps a hopeless situation :banghead.

4

In my area, I can cut any branch hanging on my side of the property line.
I’ve always asked the neighbor first to be nice.