UKH

Please, when responding to this query, imagine I am a really dim country bumpkin. I know this will not require a great quantity of imagination for many of you who have read my other contributions to this forum. 

Just ordered some nikwax techwash and some TX direct wash in. I've used techwash previously. No worries there.

However, the TX direct wash in is intriguing. Previously, I've used a spray on to revive the DWR on the outside of the jacket. How does the TX direct wash in work though? Does it not apply a DWR to both the inside and outside thereby ruining breathability?

Please help!

Yours,

Confused of Devon

I believe breathable fabric work by allowing water vapour to pass through the fabric but not allowing liquid water so shouldn't matter if it has DWR treatment on both sides as only the vapour will be passing through anyway.  

That seems logical. Thanks Andy!

The tiny holes in fabric itself is where the breathability comes from. The techwash unclogs the pores in the fabric that over time get blocked by body oils and dirt. The wash-in gives the jacket water repellency, which makes the water run off it (like a teflon pan). If the DWR treatment is starting to go, water can saturate the jacket, which can block the tiny pores in the jacket prevent it from breathing. This stops sweat from escaping and gives you an unpleasant day out.