Any water lines in a crawl space that don't have insulated walls should be insulated unless you live in climates that temperatures don't go below freezing (32F). I recommend that you use all the inside walls as much as possible for your water lines. You can also insulate your crawl space walls then you shouldn't have a problem on your non insulated water pipes as long as your crawl space is below your frost line. In colder climates its against code to plumb water lines in exterior walls.
Most is concealed in the walls. The remainder is in the attic space and crawl space or on the ceiling of a full basement.
Lice do not crawl on walls but if they ecscape from your hair they will die within two days.
construction insulation is the insulation that would be used in the walls or crawl space to keep the cold out and heat in or the other way around. it also helps with the noise level in a home.
It should be lighter. This opens up the space more.
No. Are there undetectable walls in outer space? Possibly. We can't detect them.
Spiders have little hairs on their body that allows them to crawl up walls.
It's safe to be in ceilings otherwise it will kill by human hand.
A walk-in bathtub should not take up much more space than the regular bathtub it will be replacing. It does have higher walls, though that should not be a problem. Many models have doors on which open inwards, so they do not require extra space.
They can still crawl, they have a "foot". Please refer to the recommended sites for more detailed information.
Instead of pouring a concrete slab for your floor you can have it built out of engineered i-joist. They do this by building concrete footings with a stem wall on top of that. They will then pour footings for pony walls or post and beams to support the i-joist's. They will then run the joist over the pony walls which will create your CRAWL SPACE. This also gives you the ability to fully insulate underneath the floor and have access to your plumbing if you run into problems with that later on. its also a little more forgiving when your children take those tumbles to the floor.
In my opinion just leave the ceiling white. If you paint it the same color as the walls it makes that space seem smaller or enclosed like a box.
No, that would be a terrible mistake, piping is sized by fixture units (7.48 gallons) and just to reduce the size and leave a space for bacteria to incubate is not the greatest idea