Yes, you can use a waterproof spray on a down jacket, but it's important to understand what it does and what it doesn't do.
Using a waterproofing agent, such as a product designed for technical outerwear like Nikwax TX Direct, will apply a layer of DWR (Durable Water Repellent) coating to the fabric surface of your down jacket.
What Waterproof Spray Does
- Adds or Replenishes DWR: Most down jackets already come with an initial DWR coating applied by the manufacturer. Over time, this coating wears off, causing the fabric to absorb water instead of beading it up. Spraying replenishes this layer.
- Improves Water Beading: When the DWR is effective, water droplets will bead up and roll off the fabric surface, preventing it from becoming saturated or 'wetting out'.
- Helps Maintain Breathability: By preventing the outer fabric from absorbing water, the jacket's breathability is better maintained, allowing internal moisture vapor to escape.
Limitations: Not Fully Waterproof
It's crucial to understand that applying a waterproof spray will not make a down jacket fully waterproof.
As the reference states, to be fully waterproof the seams also need to be taped. Waterproof spray only treats the surface fabric. If the seams are not sealed or taped, water can still seep through the stitching holes, compromising the jacket's water resistance, especially in heavy or prolonged rain.
Essentially:
- DWR Spray: Makes the fabric water repellent (water beads and rolls off).
- Fully Waterproof Jacket: Requires water-repellent fabric AND sealed/taped seams to prevent water entry at stitch points.
Why Apply Waterproof Spray?
Applying a DWR spray is primarily used to restore the original water-repellent function of the outer fabric, extending the jacket's life and performance in light rain or snow. It helps the jacket shed moisture effectively and prevents the down insulation from getting wet, which would cause it to clump and lose its insulating properties.
How to Apply DWR Spray
Applying a DWR spray is usually a simple process:
- Clean the jacket: Wash the jacket first using a cleaner designed for technical outerwear, as dirt and detergent residue can impair DWR effectiveness.
- Apply the spray: Follow the product instructions carefully, typically spraying evenly onto the damp or dry outer fabric.
- Dry the jacket: Allow the jacket to air dry or tumble dry on a low setting if recommended by the jacket's care label and the spray product instructions (heat often helps activate the DWR).
Key Takeaways
Here's a summary of using waterproof spray on a down jacket:
| Action | Outcome | Limitation |
|---|---|---|
| Use Waterproof (DWR) Spray | Adds/refreshes water-repellent fabric layer | Does not make the jacket fully waterproof |
| Effect on Fabric | Water beads and rolls off | Water can still enter through unsealed seams |
| Purpose | Restore surface water repellency | Not a substitute for taped seams in heavy rain |
Using a DWR spray is a good way to maintain the water-repellent performance of your down jacket's outer fabric, helping it stay drier and warmer in damp conditions, but remember it doesn't provide the same level of protection as a jacket with taped seams designed for truly waterproof performance.
