I have a few Montane Terra Stretch equilibrium shirts, which are an unlined Pertex Stretch Equilibrium pull-on shirt and are good for cool or windy days. I've used these in the past for running with good results, since the Pertex wicks up moisture and dries it out quite quickly.
I re-proofed one of these on the outside with the spray-on version of Nikwax TX Direct recently. The outside is now satisfactorily water repellent but so is the inside - when running, sweat pools inside the fabric rather than seeping through to the outside where it can dry off. It's a very unpleasant effect.
Of course, poor Nikwax can't make their solution tell the difference between the inside and outside of a shirt, and this effect is presumably inevitable if enough of the DWR solution soaks through to the inside. From forum threads on here, I'm aware of similar problems with the lined variety of windshirt (like the Montane Litespeed or a Buffalo) and the wash-in variant of Nikwax, where DWRing the internal pile effectively drives moisture back against the skin. But has anyone encountered a similar effect with an unlined shirt and spray-on applications? I can't decide if I've just been too gung-ho with the spray bottle and soaked too much onto the fabric, or if this is just an inevitable consequence of reproofing.
