Jalie 2321 Waterproof Pants

Back in the day, when we lived in Sacramento and spent a lot of time hiking along the coast or in Oregon, rain gear was essential. The only waterproof breathable pants available that were long enough were Arc’teryx Beta AR. I learned how vital breathability was when we bought just waterproof pants because they cost a lot less. Hiking in waterproof pants with little or no breathability was a big mistake! Eventually, we were able to save enough money and buy Arc’Teryx pants. Purchased in 2012 for $350, the pants have lasted us 10 years! However, it’s time to update our rain pants, and because there’s no way I’m spending $500 (current price for the Beta AR pants) on a pair of poorly fitting, boring black rain pants, here’s how I made my own pants cheaper and better.

Pattern

I used Jalie 2321 pattern. I sewed size V (33″ waist, 43″ hips, and 30″ inseam). The only adjustment I made was to lengthen the leg 3 inches and lower the center front waistband ½ inch. I also made the pants without a lining, which greatly simplified the sewing.

The size range for the Jalie 2321 is limited (23 – 53 inch hips), and right now, I can’t find the new company that’s making outdoor patterns for larger hip sizes. If you are familiar with the company, please let me know, and I’ll add it to this blog post. Found the pattern company that I wanted to highlight! The pattern is Borrowdale Trousers from Sew Outdoorsy. The size range for the Borrowdale is (51 – 80 inch hips). The pattern is similar to Jalie 2321 and gives you an extended size range!

I choose the pattern because of the side seam zipper that completely separates. You never get the inside dirty when you have to put on or take off the pants with muddy and wet boots. These rain pants are like those old-school tear-away sweatpants from the 90s.

Waterproof Breathable Fabric

Let’s talk about waterproof breathable (WPB) fabrics since not all fabrics are created equal. The features of WPB fabrics are (1) layers, (2) waterproofness, and (3) breathability. What do all those terms mean?

Layers

WPB fabrics with 3-layers offer the most durability, waterproofness, and breathability. The waterproof-breathable membrane is sandwiched between an outer face fabric, typically made of durable nylon or polyester, and an inner lining that usually consists of lightweight Tricot fabric. The Tricot lining protects the waterproof membrane from sweat and body oils. The 2.5-layer fabrics share a lot of characteristics with 3-layer fabrics. However, instead of a fabric lining, a print is applied to the backside of the waterproof membrane. This makes the jacket less heavy and improves packability. The 2-layer fabrics are made by applying a membrane to the face fabric directly, with no lining or print applied. Jackets with 2-layers are considered for emergency use only since durability is questionable. For sewing, a 2-layer fabric is great if you plan to include a lining on your garment. For my pants, I used a 3-layer fabric since I didn’t want to include a lining.

Waterproofness (Hydrostatic Head)

Measured in millimeters, the hydrostatic head indicates the pressure of water required to penetrate the fabric. Waterproof jackets range from 10,000 to 30,000 mm. The higher the value, the better. Wind, heavy rain, the weight of your backpack, and your movements put pressure on the wet fabric and will cause the fabric to leak. Therefore, waterproof garments are also treated with DWR (Durable Water Repellant) to repel the water and thus reduce the amount of water that passes through the fabric under mechanical pressure. Of course, the quality of the seams will also affect whether you will get wet; taped seams are necessary to maintain waterproofness. More on taped seams later.

Here’s a list of RTW brands plus fabrics available for purchase ranked from best to worst for waterproofness. Highlighted is the fabric I choose:

• eVent 3L – 30,000
• MONT Hydronaut / Pro 3 – 30,000
• GORE-TEX 3L – 28,000
• GORE-TEX Knit 3L – 28,000
• GORE-TEX Pro 3L – 28,000
• GORE-TEX Paclite 2.5L – 20,000
• Outdoor Research Pertex Shield 2.5L – 20,000
• Patagonia H2No 2.5L – 20,000
• North Face HyVent 2.5L – 15,000
• RBTR 3.3 oz Ventek 30 WPB – 10,000
• eVent DVstorm 3L – 10,000
• Helly Tech Performance 2.5L – 10,000
• Marmot NanoPro 2.5L – 10,000
• PolarTec NeoShell – 10,000
• RAB Proflex 3L – 10,000
• RBTR 1.4 oz 10D WBP – 9,000
• Nike StormFit – 5,000
• RBTR 0.74 oz MTN 7D Ripstop Nylon – 1,000

I’ll talk about which of these fabrics are readily available for purchase below, but essentially for a waterproof fabric, the only options are Polartec NeoShell and RBTR 3.3 oz Ventek 30 WPB. The rest of the waterproof options (10,000+) don’t have fabrics available for purchase. I don’t consider fabric waterproof if it’s rating is below 10,000.

Breathability (Moisture Vapor Transmission Rate)

Measured in grams per square meter per day, MVRT tells you how much water vapor can pass through the fabric from the inside out. Lack of breathability means you’ll get soaking wet with your own perspiration! Rain jackets with less than 10,000 g/m2/day are suited for minimal to no activity. Jackets with an MVTR of more than 15,000 g/m2/day perform superbly for highly aerobic activities such as skiing and running.

Here’s a list of the same fabrics now listed from best to worst for breathability. Highlighted is the fabric I choose:

• eVent DVstorm 3L – 30,000
• RAB Proflex 3L – 30,000
• RBTR 1.4 oz 10D WBP – 27,000
• GORE-TEX Pro 3L – 25,000
• RBTR 3.3 oz Ventek 30 WPB – 22,000
• eVent 3L – 20,000
• MONT Hydronaut / Pro 3L – 20,000
• GORE-TEX Knit 3L – 20,000
• Outdoor Research Pertex Shield 2.5L – 20,000
• Marmot NanoPro 2.5L – 17,500
• GORE-TEX 3L – 17,000
• GORE-TEX Paclite 2.5L – 15,000
• Patagonia H2No 2.5L – 15,000
• North Face HyVent 2.5L – 15,000
• Helly Tech Performance 2.5L – 10,000
• RBTR 0.74 oz MTN 7D Ripstop Nylon 7,000
• Polartec NeoShell – unknown
• NIKE StoreFit – unknown

When we look at breathability measures, the only fabric that is breathable enough (15,000+) is RBTR 3.3 oz Ventek 30 WPB. The breathability of Polartec NeoShell is unknown, but some suggest it is above 20,000.