Does anyone have any suggestions for products or process around re-waterproofing GoreTex? From what I can see the basic process is this:

Wash the garment by itself with a cleansing product to clear all the pores.
Hang and allow to dry.
Spray with a waterproofing agent. Allow to dry and spray again.
Either tumble dry or iron the garment to ensure a good seal on the waterproofing spray.

Has anyone had any particular success with this process? Any recommended products? Any to avoid? I've heard that washing in a waterproofing agent is a bad idea because it stops the garment being breathable.

Thanks 

I think you are screwed

Basically Gortex jackets have some number of layers.  Good ones using pro shell have 3.  So that is an outer protective layer, then the gortex membrane that is bonded to the outer layer then an inner meshey type layer to protect the gortex from your body.  What basically happens is when the coat is good and new, the water beads on the outside and it is nice and dry inside this is where the gortex membrane fibres poke through the outer layer.  After about 3 trips water starts soaking into the outer layer and no longer beads and you may feel a little damp but not wet.  You can somewhat revitalise this by washing the coat and giving it a warm iron (or tumble dry) that ‘re water proofing stuff helps’ or the washing stuff you get helps too .  Gortex doesn’t really like body oil and that does cause it to break down so regular washing of your coat will help the life of it.  Once you get to the stage where you are at where the coat leaks, the gortex membrane has probably broken down (particularly on shoulders and back of the neck) sometimes if you look carefully you can see perishing but often it is not obvious apart from your coat feeling like an expensive sive when it rains.  At the leaking stage the revitalising stuff does little to help, you spend money on it, douse your coat in it and it may give a half reasonable effect for about the first 15min of rain.  I have heard of other people giving this stuff a go with their leaking coats and I havent heard of one sucess story.

So basically gortex is expensive crud that doesn’t really last very long… is it really worth the money??  Well there are not really many other alternatives apart from PVC (where you will get wet on the inside through sweat).  If you get more than 3 years out of your coat before it leaks you are doing really well.

If your membrane is degraded from too many sweaty bush tramps then you are, indeed a bit fucked. Best bet is to not sweat :)

But otherwise, good jackets only wet out (don't beed, absorb!) once dirt (hydrophilic (likes moisture)) gets in the pores. As you said, a wash with grangers 30 deg (what arcteryx recommends and seems to work well) should sort that out. I think its best to wash it, spray it with a DWR (avoid wash ins for a few reasons) and then tumble dry.

 But yeh, wash your jacket every 10-20 days of use i think, good to get the oil out of the 1st layer and dirt out the face fabric, and shouldn't need DWR if its washed properly.

I've also heard (and it makes sense to me) that spin drying is not a good idea as it forces water through the membrane at high pressure. Drip dry only.

Not practising self arrests in your good jacket probably also helps.