Thanks for your review!
For some clarification our books sleeves are NOT water proof nor are they advertised as such. They are made out of cotton or cotton blends & wadding which is porous and will not protect against water. Even if we were to add a zip the water could easily seep through the fabric and cause damage. Please do not rely on book sleeves to protect against water unless they are made from leather, vinyl or another water proof material.
We do not add zips purely because of the damage they can cause to your books. During our testing period back in 2018 we trialled zips and found that they can easily tear or mark the covers, especially the dust jackets on hardcovers and soft paperbacks. For that reason we will not utilise these on our products.
Hope this clears things up in regards to your concerns
Thanks,
Eliza