Ground cloth debate

[Franco]

If the groundsheet is a bit larger than the floor and or somehow gets water over itself , you could then , with your weight, cause some moisture to come through the floor. So the trick here is to make sure the grounsheet is a bit smaller than the tent floor and it is positioned so that it does not stick out.
To better understand how water can penetrate, keep in mind that a tent fly with a 1500mm waterhead will keep the rain out most of the time, a rain jacket needs to be in the 5000/10000mm range to do the same. Old timers will remember canvas fabric to be waterproof but you could brake that surface tension simply by touching it and then water would drip in.

[Patrickjd9]

If the groundsheet is a bit larger than the floor and or somehow gets water over itself , you could then , with your weight, cause some moisture to come through the floor. So the trick here is to make sure the grounsheet is a bit smaller than the tent floor and it is positioned so that it does not stick out.

This is the main problem with a groundsheet, having to be careful to make sure it doesn't protrude from under the floor.