OK, as I suggested in my preview post. ...... So I am fairly certain that people "finish" their basement because it does not leak, rather that the process of finishing it preventing leaks.

Conversely if a finished basement leaks it makes an unholy mess, requiring demolition and tear-out to find, remove and/or prevent potentially dangerous mold.

Most basements I have seen in the US so far would not be up to scratch in the UK regarding water ingress/damp.

From our perspective in design (Architect) basements are rarely included provided primarily due to the cost of construction and waterproofing. Insurance warranties can also be fun to contend with.

Had one recently where we needed the space in the basement to hit the sqm required but had to de-water the ground at a cost of over £40K. If it hadn't had a final price tag of £1.3mil it wouldn't have happened.

Given the choice I'd always put basements in as it seems like a no-brainer for maximising land value/living space but as mentioned above: cost nearly always plays the defining part.

Just about (if not absolutely, can't remember for sure) every house I've been in in Illinois and Wisconsin has had a basement of some sort. Our current house has a full basement, of which the garage is a part, but due to the grading it's not fully underground - only about 4' at the deepest part is below grade, and less than 2' at the shallowest. We've been there 6 years, the house has been for 15 and so far no sign of leaks, though

One of these days, ours will be like that. Hopefully we can avoid having to put in a drop ceiling as well ...

Not sure if this is what you mean or not, but with regard to the houses that I have lived in, the basements were completed as an integral part of the living space when the house was built, this was not something done after the fact. (Though obviously companies advertise every day that they will waterproof your basement and give you added living space!)

Correct. The only part of my basement left unfinished is where the water pipes are.......the time it flooded due to a frozen pipe the water went down a drainhole in the unfinished laundry room floor, though apparently there was enough water to drench the carpet at the bottom of the stairwell. There is also a small 3/4 bathroom that does have drywall and tile floor. That part was also flooded but obviously was easily mopped up.

OK, so that it slightly different because if the intention at the outset (prior to the foundation being dug), was to "finish" the basement then the grading, drainage, and waterproofing would (should) be to a higher standard. It is not uncommon though for houses to be built with a basement not dissimilar to a garage - concrete floor, concrete block walls, and then to later "finish" it, and if there is later a leak it can cause a big problem.

The later finishing of basements become more common in areas where the price of housing has skyrocketed and people have been tempted to take what had originally been intended only as a cellar or utility space and turn it into "living space", or even a self-contained living unit.

That's the other "finishing" aspect I should have mentioned -- our basement has a completely "normal" ceiling like the rest of the house; it was constructed with everything hidden in the way that is usual between the formal living and sleeping levels.

I think 99% of the conduit and piping running along the ceiling of our basement is 'above' the bottoms of the studs, and those parts that aren't can, I believe, be moved. It looks like, apart from framing around the I-beam, we should be able to have a normal ceiling in ours and take advantage of the fact that that built the house with the same 8' ceiling they have upstairs down there too.

Plus, we plan to add a 4th bedroom in the basement as well, and who wants a manky old drop ceiling in their room?

You can only have a bedroom in a basement if there is a means of escape other than the door, in the event that there is a fire that blocks the usual doorway/access.

It'll have a window. Our basement is mostly above grade.

Of course once you've finished your basement you will inform the local assessors office who will come round and measure it to add that area to your square footage and adjust your local taxes accordingly... just like everyone else does *cough*.

Of course I will ...

FIFY

You know what though, I doubt our assessors would even know what to look for anyway. I just checked our address on the county website and apparently we don't have a garage.

Not sure what that thing I park my car in every day when I get home is then. Judging from their listings, they seem to think it's the 'finished lower level'

From what I know, most checks on such things involve the assessor driving by slowly. So if it can't be seen from the street you should be ok.