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>Cement/Concrete (based on Portland cement) is water proof That's patently untrue. Otherwise we wouldn't need concrete sealants.
by meindnoch 2mo ago
>Cement/Concrete (based on Portland cement) is water proof
That's patently untrue. Otherwise we wouldn't need concrete sealants.
- amszmidt 2mo agoThe key here is “based on Portland cement”, which is generally has water repellent added to it making it water proof. Normal cement, concrete .. Is a different story.
- lazide 2mo agoConcrete is generally porous and definitely not micro-waterproof (aka lots of water vapor makes it’s way through). Including if using Portland cement. It is generally macro-waterproof, however, unless there are large cracks.
- dnemmers 2mo agoI'm not sure exactly what you're saying is correct. 'Concrete' is a combination of sand, cement, water and aggregate, that cures together to form. When the water migrates away from the curing concrete, it leaves open pores behind that future moisture can move through. https://en.wikipedia.org/wiki/Portland_cement https://en.wikipedia.org/wiki/Portland_cement
- iknownothow 2mo agoYou are correct. I'm not sure why I remember cement to be water proof. Its possible I infered from how its been used around me. I have seen cement very often used where water contact is expected (bathrooms etc). I have also seen brick walls plastered with an extra layer of cement as putty considered to be rain proof and any leaks were thought of as poor workmanship rather than poor material choice. P.S. I'm not a builder. I've taken an interest in the topic a few months ago.
- dnemmers 2mo agoHydraulic cement is made for some of those occasions: https://www.quikrete.com/productlines/hydraulicwaterstopcementpro.asp https://www.quikrete.com/productlines/hydraulicwaterstopceme... But I wouldn't want to make any sort of building that only relied on it for waterproofing.
- DivingForGold 2mo ago[dead]
- Groxx 2mo agoMight be because it's water tolerant, i.e. it doesn't break down with exposure to water? Roman über-concrete stories are always full of "check out the concrete that's sitting in sea-water, it's still going strong! maybe it even helps!" cases too.
- DannyBee 2mo agoYou can also just see it with cement board - if you pour water on top of it, it will eventually migrate through and drip.
- throwaway173738 2mo agoAlso if you put a slab basement in a hillside in a rainy area. Water will percolate up through the slab unless you make good drains to divert the water around your foundation.