Are you going to have soil,ground water, etc around the tank tested to make sure there wasn't any leaks or spills?

I'd stay away from travertine. because of concerns about its durability- it'll chip and scratch and is porous which can be troublesome if somebody spills something on it.And, I have to disagree with choosing ceramic tile because porcelain is less likely to chip and less likely to show damage if it does get damaged whereas you'll see a different color underneath ceramic if you chip that.I put in porcelain tiles in the most trafficked areas in my place because I thought it was going to be so durable and hassle free.

The time to resell it varies on the cycle of development for that dirt.Land with a slope if more expensive to build on than flat land generally because of leveling and certain slopes require more expensive grading and clearing equipment.The soil condition and makeup is key.

If any of you have questions about problematic soils / geology, please ask, I have seen it all (expansive soils, landslides, poor foundations, etc.).

I'd start with a few:Droopy ceiling fan blades - Excessive moisture trapped in ceiling and attic, possible mold spread inside, plumbing problem, roof leak, soggy studs, possible damage to electrical wiring.Cracks on the ceiling - Possible foundation problem, roof leak, or storm and hail damage to roof.Soft spot or dip on the floor on 2nd level - Workmanship on flooring cover, water damage to wood underneath, renovations done from down stairs ceiling created damage.House extension not built on slab or same foundation as the house - Difference in foundation and level.

ALSO, due to a recent storm a branch fell on overhead electric line which a pole that was attached to house and went through part of roof was partially ripped away from house and now you can see through part of roof for underneath house.

My contractor tried to convince me that the white patches were soil chemicals leaching upwards and was typical for the area.  

Unless the DWV system is scoped, the possibility of having a main soil line in the process of collapsing.

I am in the Charlotte NC area and basements in this region are usually day lighted because how bad the soil here is for drainage.

Second, I'm not even sure how to go about borrowing money from foreign soil.