Ava, our old screened porch had a concrete floor. Rain wasn't so much an issue as the high humidity. The concrete would "sweat" during the summer months and was just plain nasty. Dh eventually covered the concrete with pressure treated pine and it made all the difference in the world. It brought the floor a couple inches off the ground and totally changed the "feel" of the porch. Made it much more inviting.

A couple months ago we tore down that porch and the attached garage in prep for the new addition that's going up right now. We'll have a new screened porch 18" off the ground and this time floored with Ipe.

Here are a few pics of the old one.

Natal -- Thanks for the word of warning and for the great photos! It gets pretty humid here in the summer, so I'll bet sweating would be a problem for us too. (I remember our awful sweaty basement floor when we were growing up -- must've been a mold factory).

Your porch and landscaping are beautiful! I do think some sort of wood flooring is the way to go -- I just have to figure out 1) how to get it into my renovation budget and 2) what material is relatively sustainable since I'm trying to do the "green" thing whenever I can.

Good luck with your addition!

Ava

springvillegardens -- Wow! That's a fantastic paint job. Thanks for sharing your photos and knowledge. Do you know if it is the case that if you seal the concrete from moisture below the slab (e.g., with a vapor barrier if it is on grade) and from above with a sealant, you essentially prevent the concrete from ever having "sweat" problems?

Ava

Ava, thanks for the compliment - I am still perfecting some of my "tiles". We are so happy with before and after - we are now painting our garage inside.

I have been reading up on concrete products and there are some new onces on the market - but I also think that sweating has to do with moisture condensing - not being a scientist - I am not sure that you can prevent sweating in all situations - but I have been told that a moisture barrier underneath helps. We don't have that problem so much in California - but when we lived in Arkansas which is more humid - we had that problem and folks there used a thick mil plastic under concrete to prevent moisture from coming up from below. I would assume that if no moisture wicks from below and the concrete is sealed from above then you shouldn't have sweating - but condensation comes from changes in temperature - so maybe you would still get sweating ???

This is more technical than I have knowledge for - maybe someone else knows - too bad there isn't a concrete forum - that's a whole other topic and since concrete is being utilized more and more - we sure could use one.

Update - Invisoseal and Ultrapel are not suited to painted or non pourous surfaces - the branch manager is going to send me a sample of Crystal Seal so I can test it on my patio - I will post after the test to let you all know the results.

springvillegardens--Thanks for the follow up. I happened to speak to a Portland Cement rep at a building expo today, who confirmed that we should use a thick moisture barrier, followed by a layer of sand, and then the conccrete, to prevent moisture from getting into the concrete.

I'm confused about the branch manager's comment about painting on non porous surfaces. Isn't the concrete porous? (Thus the moisture problem?)

Happy sealing,

Ava

Ava,

I think the branch manager meant, if the concrete is raw or unpainted - then it is porous, once it is painted with any type of paint including an acrylic epoxy paint it is no longer porous. Therefore the type of sealer I would use would be different than if I had used a stain on the concrete - with a stain the concrete is stil porous but with an acrylic epoxy the concrete becomes non porous.

Since that time I talked with the woman who originally put this treatment on her restaurant floor and she used an oil based varathane. However, I am going to use a water based or acrylic based varathane on mine. I have talked to several people and the water based sealer has less of a tendency to yellow than the oil based. Also I am thinking if I want to change the color or redo the concrete floor in the future, then I am thinking it will be less troublesome to redo a floor with a water based product.

One point - I have tried using varathane with a roller before and it tends to put little bubbles in the finish, so I am going to use a flat sponge to apply the varathane. The woman doing the restaurant floor used a flat applicator to apply the varathane too.

I am going to try my garage floor this week and will let you know how it turns out.