1. Stormproof And Water-Resistant Bivvy Sacks
The bivvy sack is as simple as outdoor shelters get. It allows you to be closer to nature while being
protected from the elements. They're very light, easy to set up and can be pitched anywhere there's
enough room to lay down. Most people set up their bivvy in order to get a good view when they wake
up in the morning.
Storm proof Bivvy
If no water can come into the bivvy sack, it can be considered as storm proof. It can be used in the
worst weather as a standalone shelter. Water can get inside a bivvy either through the fabrics, the
seams or the opening of the sack. Gore-Tex is commonly used as a waterproof/breathable fabric in
storm proof bivvies. Fabrics like these not only prevent water from seeping through but allows vapor
to escape as well to prevent unwanted condensation.
The floor does not need to be breathable so all it needs is a waterproof fabric. Silicone-coated nylon
is typically used for the floor. The main function is to keep water from seeping through from the
ground. It's important for the floor to be able to maintain its waterproof properties so it has to be
durable as well.
A bivvy sack can only be considered as storm proof if it can totally prevent water from seeping in by
having sealed seams and waterproof closures.
Water Resistant Bivvy
A water resistant bivvy sack does not have sealed seams, waterproof fabrics and waterproof
closures. You don't need waterproof bivvies all the time. Waterproof fabrics, seam sealings and
waterproof closures add weight to a bivvy sack. That's why water-resistant sacks are much lighter.
One less obvious advantage is that water-resistant bivvies are less prone to condensation. The type
of fabric used removes vapors very quickly before it has the chance to condensate. Combined with a
tarp, this type of bivvy works very well. This may mean you have to carry some extra weight but only
a small amount of tarp is required and you may not have to worry about condensation so much.
The bad news is, no fabric is good enough to completely eliminate the risk of condensation inside a
bivvy. Condensation occurs when a warm body in a confined space is mixed with cold temperatures
outside. The head end and the foot end of the bivvy sack is susceptible to condensation. The risk is
increased when the weather is humid but if there is good ventilation it is less likely to occur.
Bivy Tent