Sealing Concrete?

[Dan Hunter]

I just had my shed completed. It's a 30 X 40 Mueller with a 10 X 40 lean to covered patio. I'll wait until it's completely cured to seal it but I'm confused by varying products and guidance. Some require sanding or etching to bring the surface texture to 200 grit. Well I don't have water to rinse acid or power to run whatever sander to rough it. Further, I've found a product for rough or hand traveled surfaces which is what I have - it didn't see a rotary polished and wasn't rained on after trowelling which might reduced surface porosity. So yes it's rougher than 200 grit everywhere.

I read a reference regarding spilling water on the surfaces to check porosity but couldn't find specifics.

What I'm wondering is if I can avoid etching and sanding if my surfaces weren't polished?

 

[Gary Fowler]

With most any coating on concrete, you will need to remove the "laitance" (loosely bonded cement on top of the concrete) prior to putting on a coating. I would suggest a high pressure washer in your case to water blast the top prior to putting on any coating. A 2200-2500 PSI pressure washer should do you fine.

 

[pinetree10]

I built a garage last year and the day after the floor was poured I applied a commercial product called Cure & Seal. The mason wanted me to put it on the day it was poured but I was not inclined to walk on it when it was that fresh. It took a long time to change from green to gray - several months - which I'm told is a good thing for strength. There's a little gloss to it but it's not as sealed as I would like it to be. I didn't do any etching or sanding. Check out this link:

http://www.euclidchemical.com/fileshare/elit/cure_seal_comp_guide.pdf

 

[mjcountrybumpkin]

As far as " spilling water on it" goes its simple. Pour any amount you would like from an once to a cup full. If the surface changes colors immediately or within 5 seconds, your concrete is open enough to seal. If not it needs to be etched.
As far as sealing goes a good $10 garden sprayer would work well for application. I always found it easier to seal when the sun was not at its hottest. If it get really warm or sunny the sealer can dry before it fully penetrates the slab, causing the finish to be weaker and not last as long.

Good luck

 

[Texasmark]

My first shop was sealed with a milky looking sealer applied as directed. It was not the kind of sealer you see folks use on their garage floor, basically painted on and thick. The floor still sweated even though I had a vapor barrier down prior to steel and crete. It still absorbed oil spills to the point of remaining visible after removal of the spill.

My current shop was built in '05 and I didn't bother. The floors look the same after a few years usage and still sweat on occasion....humid warm day after being cold.

HTH,
Mark