Galactic wrote: ↑28 Sep 2022, 3:23pm
Definitely seepage from below rather than condensation - the floor fails your bucket test
If it fails the bucket test then it's a duffer, whether that's from accumulated wear and tear (in which case you need it replaced at your own cost) or faulty manufacture (in which case it should be replaced by the seller).
On to condensation...
Tent fabrics will have a stated hydrostatic head figure, well in excess of a meter for groundsheets, which means the fabric will withstand water of a column over a meter high. Bear in mind that a fairly flimsy carrier bag (assuming no holes) can pass the bucket test and you can see that "waterproof" isn't actually that big an ask... but that same carrier bag can give us some insight as to how much condensation can be an issue. Put something cold and wet in your bag (a trip to the fishmonger shows this perfectly) and even though the bag doesn't leak, the outside gets wet because you've got an excellent heat trap (the cold, wet thing that is an excellent conductor of heat), a good condensing surface (the bag) and typically quite moist air (in the atmosphere) all together.
And that's what tends to happen to tent floors when they're on cold, wet ground, and the thinner they are the more they suffer. You tend to get condensation [Edit to clarify: "obvious wet patches", you get condensation other places, but not in obvious wet patches] under pressure points (i.e., under mats, and under knees when kneeling) [Edit to clarify: think of the fine mist of droplets on a "steamed up" window, push a finger against it and you leave an obviously wet-looking spot].
I've never had a leak from the floor in any tent (variously classic Force 10s, Saunders and Hillebergs). I've quite often had wet floors from condensation, with the thinner floors more prone. Footprints help because even though they're thin it's insulation from the cold that causes moisture to condense out of the air.
But there are times when even with a fairly stout groundsheet and a footprint you'll get condensation, because physics. To eliminate condensation in lightweight tents, don't go camping...
Pete.
Often seen riding a bike around Dundee...