Sealing an old concrete garage floor

[Pappy B]

I have tried a search for my exact question with no luck. So I will post it here.
I have a 1942 service station that has some additions from 1946. The whole thing is a perfect non cracked slab with appropriate expansion joints. I am enclosing about 800sf of the 2500sf from the rest of the garage for a clean club house. As I said the floor is perfect condition with the exception of cool patina from old paint etc. the section I am enclosing was already mostly enclosed for a storage/living qtrs. so there is not any oil or solvent staining to speak of. I plan on doing a deep clean on the floor and I will be leaving some of the old patina for character what little bit of paint that will remain has very very little millage. What sealer would one recommend for this? Also to note The space is not yet insulated or conditioned however it will be sometime this year. The floor has a tendency to get damp when its humid or the temperature has differential from outside to inside. This should be remedied once close, insulate and condition the space. until then I will be adding a ventilation fan in the whole garage in order to maintain equal temps between inside and outside. should I be concerned applying said sealer even if I do so when its dry?

 

[CombatNinja]

The first thing you are going to need to do is determine where the moisture is coming from. Condensation from a huge temp differential from the air in the room to the cool concrete is one thing and would of course be mitigated once you condition the whole space. Moisture coming up through the slab is quite another thing and will determine what kind of sealers you can and can't use.

Do the standard moisture test in a few areas to determine what you are dealing with. Get some good thick plastic sheeting, cut out a few sections 12" x 12" or so and tape them down with duct tape really well. Let it sit for a few days, preferably when you have rain going on and see if the plastic accumulates water droplets underneath it. If so, you've got water coming up through the slab.

That really needs to be your first course of action as it will determine your strategy going forward. Your space sounds really unique and should be great once finished. Good luck with the build!

 

[Pappy B]

Thank you. I will do that today!

 

[Shea]

Are you looking for a sealer that doesn't change the look of the bare concrete or do want something that adds a clear finish?

 

[Pappy B]

Are you looking for a sealer that doesn't change the look of the bare concrete or do want something that adds a clear finish?

Something that does not change the look, Yet still clean as in I want it clean enough to walk around in my socks if I want to. Keep in mind this is just the 800sf area that will be enclosed.

 

[Pappy B]

Shea did you have a suggestion?

 

[Shea]

A penetrating sealer will not change the look of the bare concrete. One problem, however, that it will not have any effect on the areas where paint is still on the floor. Another consideration is that the concrete surface will not change since penetrating sealers are non-film forming. That means that regular cleaning, sweeping for example, would be the same as bare concrete.

The other option would be a clear topical coating in a matte finish. If all this space is going to see is foot traffic, then an acrylic would work fine. The coating will darken the color of the concrete a little bit, but it will not be glossy. It will also bring out some of the character of the concrete. Acrylics do not require any profiling of the concrete either unless it is very smooth and will not absorb liquids. The paint would need some light sanding as well so that it would adhere. Since they are a topical coating, regular cleaning maintenance can be done with a dust mop and the occasional wet mop.

 

[Armorpoxy]

Perhaps take a look at our clear SPGX hybrid one part polyaspartic/polyurea coating which gives a terrific seal with little, if any prep and is low cost and easy to use.