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Unread 04-21-2021, 01:59 PM   #7
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Join Date: Mar 2021
Posts: 16
Mapei Aqua Defense over Kerdi membrane seams (2" overlap exposed Thinset spots)

Hi all. I know, I know, it is not recommended or "required", in their opinion, I want to hear your opinions.

I hope we can agree Thinset is not waterproof. All these 2" overlaps rely on the perfect application of Thinset which is granular, even smoothed out close to perfect it has been shown that water can weep through the thinset, and more than the 1/4" max some say it should.

After deeply researching this for the last 2 months and watching many failure videos I just feel like putting liquid water proofing membrane over the 2" overlap seams, especially where thinset is exposed makes perfect sense and would keep it more waterpoof, especially in the case of a slow leak failure.

Is anyone out there doing this? What are your thoughts?
For the average shower, that does not fail, and so not a submerged application, probably 1/4" is all that would happen. I am doing a steam shower though, which kind of is a submerged application.


Last edited by jayjonbeach; 04-21-2021 at 02:21 PM.
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