Condensation & sweating.
Even in cold weather, your horse will perspire, and if a garment does not have sufficient breathability, the moisture (from perspiration) and difference in outside/inside air temperature will build up as condensation on the inside of the rug. This will make your horse uncomfortable. For any turnout rug to keep your horse comfortable on the inside, both the outer fabric and the lining also need to be breathable.
If your horse decides to take a quick gallop, or get worked up, the perspiration they generate will be more than a turnout rain sheet can breathe away. Also be aware that regardless of the rugs breathability rating - in wet conditions, it will be reduced to almost zero as water covers the rug's fabric pores. This can cause condensation to accumulate on the inside of the rug. This extra moisture on the inside may also give the illusion that the garment is letting water in from the outside, when in reality it is your horse’s perspiration and condensation from the difference in outer air temperature.
When using rain sheets, we always suggest using a cotton under rug in humid, extended wet or cold conditions as this style of rug will help wick away the horse’s perspiration and condensation that needs to be transported away from their coat. A horse can perspire up to 1 litre per hour.
If you have ever worn a raincoat yourself on bare skin on a cold day in the rain, you will know how clammy and uncomfortable it feels as the condensation builds up against your warm skin.
Water will eventually wick its way up a horse rug's interior lining or via under rugs.
The inside linings of the rugs progressively absorb moisture by a natural capillary action when water collects on the drip lines and bindings of the rug.
This is accelerated if you have an under rug hanging out a few millimetres from the top rug. This fabric functions something like a sponge, sucking up the rain as it falls off the outer rain sheet. It's more important to consider the amount of time spent than the amount of rain needed for this to occur.
For example, 10mm of rain falling in 5 minutes won't have much of an impact. Nevertheless, 5mm spread out over 10 hours gives more opportunity for capillary action allowing water to wick its way in.
At Canter for Cancer we use large tail flaps, but water entry around the tail flap is unavoidable. A tail flap is a separate attachment to the main rug, and it's normal in any horse rug to get some water entry in via the stitching that attaches the rug and tail flap together. We are yet to find a fool-proof way to get zero water entry in via the stitching (as is any other manufacturer). On a correctly fitting rug the tail flap seam should be situated below the top of the horse's tail.
How long does a denier rugs waterproofing last?
Treated correctly you should get a good life out of your turnout, but it depends on a few factors.
- washing a rug will shorten a waterproof membranes life. Avoid top load washing machines that agitate and twist rugs.
- avoid harsh detergents
- never use water over 35ºC, hot water will destroy the membrane.
- leaving rugs out in the sun, when not in use, will cause the membranes, overtime to get brittle
- some shampoos and coat conditioners can be acidic and damage the membrane.