Friday, 18 December 2009

Groundsheet on the Inner Tent, why?

I never gave it much thought before but looking at the various Tarptents from Henry Shires I got the idea that you could easily add a floorless inner tent to create a double skin tent, in fact Henry provides something similar, a Clip-In Liner for the Double Rainbow.

That got me thinking about double skin tents in general, why have the groundsheet and for that matter the mesh doors attached to the inner tent? Imagine if the groundsheet and mesh was permanently attached to the fly to which you added the floorless inner. You could use it as a single skin with full groundsheet and midge protection if you wanted to reduce weight and simply add the inner when needed.

There doesn't seem much to be gained by attaching a groundsheet, which will probably end up wet and muddy, to the inner tent which ideally you want to remain clean and dry but thats how every tent I've ever seen has been designed, any ideas why this is? wouldn't it make more sense to have the fly/groundsheet together as both are likely to be wet anyway.

The best reason I can come up with is that maybe historically tents were canvas/cotton with a sewn in ground sheet to which they later decided to add a nylon waterproof 'Fly' and thats how they've remained, just conventional. Is there any logical reason why it couldn't be done the other way?


  1. Condensation.

    At some point you'll get condensation on the inside of the fly, and you want that to run down the walls and drip off onto the ground. If the fly and groundsheet are together, it'll just run off and pool on the groundsheet.

    Saying that, there are some all-in-one shelters similar to hooped bivvy-bags, but these tend to utilise a 'breathable' fabric that is supposed to prevent condensation. Apparently.

    Also, it's quite nice to be able to turn the fly inside out for drying, either putting it back over the inner inside out or laid out seperately, and this becomes much more tricky if there's a floor involded.

  2. The point about condensation is a fair one although I was visualising the groundsheet attached to the fly with a mesh section similar for example to the Contrail/Rainbow/Moment etc with the groundsheet not directly attached to the bottom edge of the fly.

    Drying the inside of the fly would become more difficult although reversing the fly over the inner isn't easy (if at all possible)if the tent pitches fly 1st, I must admit I haven't tried.

    There are going to be compromises which I hadn't considered but personally I think I could accept them for the versatility, my Laser for example didn't allow for the inner to be detached from the fly at all with the result that condensation/rain on the fly saturated the inner once packed.

    Good points though :-)