My neighbour requests to plant an olive tree eight foot from my house extention. should i be concerned? ...

How much is mulch for your ground for...
Answers:    It would appear that the common inference for trees being implicit a house would be, House + tree = worried homeowner.

A poplar or a willow or some other large tree would inflict me concern. In the case of the two I mentioned it would be because the roots of these species desire water and are great at finding dampen and sewage pipes.

Olive however is a tender tree in the UK and I would guess, most cooler parts of the US. Therefore it is slow growing and contained by the case of the UK more potential to die of cold winters than threaten your home.

No I wouldn't worry. It's never going to win that big and modern foundations are more than a match for such a small tree.

Believe it or not I have a surveyor (yes a paid professional) once decline a mortgage because a Magnolia was growing 15-20 foot from a building. The tree may of been lower than threat from the building or the occupiers, but it be never going to be the other way around.

If the Olive ever get really big there are ways to... erm.. restrict its progress, but I wouldn't verbs for the next 20+ years. See what the winters do to it first.

Hope that help.
How do you plan and grow an life...
I don't think an olive tree would do much at adjectives. It wouldn't hurt anything.