SKJOLDR™ is Jöttnar's new proprietary windproof, waterproof, breathable fabric. In this article we take a closer look at its performance and how it works.
Key technical stats:
Hydrostatic Head: 20,000mm
Breathability rating: 20,000g/m2/24h
Durable Water Repellent (DWR) treated face fabric
What is this all about?
We don’t use Gore-Tex in our waterproof, breathable clothing. We have used Polartec NeoShell in the past and we like it a lot. It breathes well.
But the time came to develop something in-house which fulfilled our own strength, breathability and waterproofing criteria exactly, based on our own use cases and feedback from our customers. So we developed SKJOLDR™ for winter 2018, our new windproof, waterproof, breathable fabric.
What is SKJOLDR™?
SKJOLDR™ is our name for our new windproof, waterproof, breathable fabric. It comes in different grades, but the membrane is the same. The membrane provides a hydrostatic head of 20,000mm and a breathability rating of 20,000g/m2/24h. The face fabric is treated with a Durable Water Repellent (DWR) treatment.
What does hydrostatic head mean?
A hydrostatic head (HH) rating of 20,000mm means that the membrane can withstand a water column of 20m in height. This guarantees that the membrane will not be penetrated by heavy rain, even when wearing a rucksack or climbing harness with a hardshell jacket or trousers (these create pressure points in a fabric that could potentially cause leaks in a membrane with a lower HH rating in extreme weather).
What is the breathability rating?
The breathability rating of 20,000g/m2/24h means that the membrane allows 20kg of water vapour to pass through a square metre of the fabric in a 24 hour period. This high figure allows highly aerobic activities without creating a clammy, damp feeling from sweat vapour becoming trapped.
What grades does it come in?
SKJOLDR™ comes in two fabric weights, 98g/m2 (used in the Asmund jacket), and 171g/m2 (used in our Odin jacket, and the Vanir LT pants). These garments use SKJOLDR™ in a 3 layer form (with a tricot backer to protect the membrane from abrasion from midlayers).
We use 2 layer SKJOLDR™ in our Ragnarök ski jacket (this dispenses with the backer, as the membrane is protected from damage by the down fill). This helps save weight.
All the grades have a Durable Water Repellent treatment on the face fabric. This causes water droplets to bead up and run off the surface of the fabric, preventing the garment from becoming saturated (known as ‘wetting out’). A saturated face fabric massively reduces the breathability of the membrane, so a working DWR coating is essential to keep the membrane working correctly, keeping you dry and comfortable.
How does the waterproof membrane work?
SKJOLDR™ works by layering a very thin sheet of polyurethane (PU) between a face fabric and a nylon backer. The PU membrane is covered with holes which are small enough to prevent water ingress, but large enough to allow sweat vapour to escape. The face fabric and backer’s primary role is to protect the membrane from damage, which would compromise the waterproofing of the garment. All the seams are sealed with tape, to prevent water ingress through the stitch holes.
How do I look after my SKJOLDR™ garment?
As with all waterproof membranes, SKJOLDR™ requires simple, but regular care to maintain its performance. We would advise washing a jacket that is actively used on a daily basis once a month, using an appropriate detergent. At the same time, re-treating the garment with a water-repellent treatment will restore the DWR on the face fabric. Jöttnar recommends Storm waterproofing products.