Can Washable Nappies Be Re-Waterproofed?
Modern reusable nappy wraps are made of PUL which is a breathable but waterproof fabric however over time the waterproof layer can become less reliant as the factory waterproofing treatment wears.
How quickly this can happen varies by brand but is also affected on how often you wash and use your cover. You may also find that an older waterproof wrap happily copes over a daytime nappy but over a saturated night time nappy with extended wear time your older wrap could be struggling.
Before considering treating your wraps I would recommend you do some experiments and test the wrap over different nappies and at different times in the day. I would also consider boosting your nappies if they are feeling very wet in the area of any leak as often boosting takes the pressure off a wrap and solves the issue.
Reproofer can be bought in out and about stores, designed for use with waterproof jackets etc. I have met customers who have tried this on their nappy wraps but I am yet to meet one who has found it has worked.
Mother-ease Cover Revitaliser
Mother-ease make a product called Cover Revitaliser which is especially designed to revitalise waterproof covers. If your nappy wrap has delaminated (waterproof layer has separated from the outer nappy layer) the revitaliser will not fix this. Please note that as long as the inner layer of PUL that has delaminated hasn't torn it will still be waterproof and if used with care will continue to work. I was given an old delaminated cover for my second child, it actually lasted through that baby and onto baby 3 as well. I just used it at times when I knew the nappy wouldn't get super wet and was careful with handling it. If you have tears in your PUL the revitaliser will not be able to fuse the tears either. In the case of tears or crumbling PUL then the wrap is only destined to be recycled.
The Mother-ease cover revitaliser is a one time use product. You must use all of the revitaliser in one go regardless if it's one wrap or 5 that need reproofing. The product isn't cheap so it is important to consider if reproofing will be cost effective for you.
All In Ones
All in ones are NOT suitable for use with reproofer of any type. Reproofing an all in one washable nappy will result in the fabric becoming water resistant which is a recipe for disaster and lots of leaks! Only products where the waterproof PUL section can be completely separated from the absorbent part are suitable for attempting to reproof them.