Rain Covers FAQ's
W1 Are White Mountain™ backpacks waterproof?
All White Mountain™ backpack materials have a polyurethane
(PU) coating and are waterproof to varying degrees. Please visit
our page on
Material Test Reports for further detail on this subject. The
only true waterproof packs are made of vinyl and have welded seams.
Waterproof zips are available, but are very expensive and can more
than double the price of the finished backpack. There are water
resistant zips now available on the market, but White Mountain™
have not approved the use of these zips in the manufacturing of
White Mountain™ backpacks.
W2 Are the seams on White Mountain™ Backpacks
While not entirely waterproof, all interior seams are bound with
a polyurethane proofed nylon webbing that reduces water penetration
to a bare minimum. If you think it necessary and wish to further
waterproof the seams, you can seam seal all seams with a liquid
silicon seam sealer, available from most outdoor stores.
W3 Are Internal Liners necessary?
Some backpackers avoid external rain covers completely and use
internal liners instead. These less expensive internal liners are
heavy gauge plastic bags similar to what you'd see as a garden waste
or a survival bag. Others opt for Dry Bags, which are actually designed
for canoe or kayaking trips. The dry bags are far more durable than
plastic, but also weigh considerably more. The advantage of an internal
liner? You still have ready access to the backpack. The disadvantage?
The backpack is not protected on the outside.
W4 Bivvy Bags
We recommend the use of bivvy bags in all circumstances, especially
with hiking backpacks. Bivvy Bags will protect your gear from water
and allow you to organise your backpack for ease of access. The
use of different colored Bivvy Bags is recommended and will enable
all your stored equipment to be color coded for ease of identification.
W5 Are Rain Covers Necessary?
Most backpacks have a waterproof polyurethane (PU) coating, that
means water won't penetrate the backpack, right? Well actually,
NO! Polyurethane (PU) coatings prevent water entering through the
fabric, but don't prevent water from getting into the backpack through
the seams and through the zippers. Bear in mind that lower quality
backpacks have less stitching over a given area, and use a inferior
thread. Inferior threads are not tensioned enough to form a tight
bond on the adjoining materials, and this can easily be demonstrated
by gaps formed when gently pulling on these adjoining materials.
When fully packed a lower quality backpack will expose these gaps
and allow greater water penetration. A backpack with higher quality
thread that is stitched and tensioned to prevent gaping will prevent
excessive water entering the backpack, particularly if bound internally
with a waterproof nylon tape stitched over the exposed seam, as
in all White Mountain™ backpacks..
W6 What is the correct Rain Cover Size Selection?
Care must be taken in selecting a Rain Cover size. If you strap
gear on the outside of your backpack, you'll want to make sure that
the Rain Cover will fit over all of the backpack, external attachments
and all. A generic XL Rain Cover should be large enough to cover
all the gear. A personal choice on size is one reason we do not
sew Rain Covers to the backpack, another is that Rain Covers are
generally only required in severe weather conditions.