Questions: Concrete Prep, Propane Heaters

[Tidybuoy]

I'm in the process of prepping my garage for epoxy coating which I will be doing the weekend after next. So far, I've ground the edges with an angle grinder and diamond blade. I rented a floor polisher with a diamond blade and sanded the floor last night.

Unfortunately, the floor polisher was not abrasive enough to sand down the 1/2" lip in the center so I will be renting the "big" machine this weekend to finish. I will follow everything with acid wash and many rinses.

The product states that I need 48 hours drying time before applying epoxy. And, it should be applied between 60 and 85 degrees. At this time, the low temps at night is around 50 degrees and so I was going to use a propane heater to keep the garage warm overnight. Although, my garage is insulated and seems to be warmer than the house in the morning.

A friend of mine (an engineer) tells me I have to use an electric heater and not propane because propane will increase the humidity.....Does that sound reasonable? I figure I will have at least 3 fans running and the heater and I can't imagine the humidity increasing so much as to ruin my project. He started quoting the elemental table so he may know what he's talking about but I don't think I will be affected. Out normal humidity this time of year is around 35%

My one worry is that my garage has a wood sill plate (not concrete) and so I want to make sure it is completely dry before my epoxy job (even though it's not getting painted). And, I will have fans running for about a week before painting.

Some progress photos:




The Dust:


My Baby's:

[Tidybuoy]

One more question:

Should I repair this concrete with some type of concrete patch or and epoxy filler?

This is my tool shop which was originally a tool shed outside of the house. When I rebuilt the shed, I opened the wall to the garage and this is why there are two separate slabs. The step up will be dealt with using some type of threshold and I will not be epoxying the 2" gap between the slabs.

[cabmandone]

I tried to tell ya those things don't get the plan... but did ya listen? Nooooooooooooo.

For the spalling and other repairs, I used an epoxy product to repair the floor. I think it was Rustoleum epoxy shield floor patch.
After you use the floor grinder that is right for the job, don't bother with acid etching. You're effectively doing with the grinder what the acid etch does which is open the pores to allow the epoxy to soak in somewhat and bond. If you feel you must use acid, rinse with a baking soda/water rinse to neutralize the acid. I'd just clean up the dust, rinse the floor down well and let it dry. Once dry, place a piece of plastic taped down on the floor to make sure you don't have moisture trapped in the concrete. After 12 hours, remove the plastic and see if water vapor is present. If it is, get a big home dehumidifier and let it run for a day to pull out the moisture.

The important thing here is floor temp as well as ambient air temp. If the floor temp is too low, you won't get a good cure before you topcoat with clear.
OH! And for the heater, I'd go electric. Moisture is a byproduct of combustion. Any ventless gas heater will add moisture. I think can rent those 220v hanging heaters (the ones that are small squares like 16"x16") at a lot of rental places. If you do go propane or gas, run a dehumidifier at the same time. The nice thing is, the dehumidifier will put off some heat as well to help heat the space.

[cabmandone]

Originally Posted by Tidybuoy

One more question:

Should I repair this concrete with some type of concrete patch or and epoxy filler?

This is my tool shop which was originally a tool shed outside of the house. When I rebuilt the shed, I opened the wall to the garage and this is why there are two separate slabs. The step up will be dealt with using some type of threshold and I will not be epoxying the 2" gap between the slabs.

For the step up, I'd probably use a vinyl bonding cement patch. It's compatible with most epoxy. I'll see if I can get a picture or a name of the Sakrete product I used for a large crack I had to repair.

[TimT]

I have to use an electric heater and not propane because propane will increase the humidity.....Does that sound reasonable?

Burning propane produces water vapor...

Why Burning Propane Makes Water

Use electric, or vented propane..

[cabmandone]

Okay! So to correct myself, I used Rock Solid Fast Patch kit. Bought it at Menards. I used it to repair spalling and as a finish for the large patch I mentioned I had to do. For the buildup patch I used Sakrete Fast Setting Cement Patch. This stuff can go on thick to repair the edge you pictured. This is where I'd etch, rinse and apply the product. The key is to keep it moist while it cures. I used plastic taped to the floor to hold moisture while it cured. You might consider using a concrete bonding additive. All pictured below.Hope this helps

[Tidybuoy]

Thanks! This is a big help.

[billybek]

Look up"indirect fired construction heaters".
Looks like a fun project.

[cabmandone]

Originally Posted by Tidybuoy

Thanks! This is a big help.

I'm glad the pain I went through this spring can now help others.

If you haven't gotten a floor surfacer to finish the floor yet, Hertz Rental has a Husqvarna floor grinder that you buy cutters for that does an excellent job. It's a 10" head but it's FAST. I think there's a tool that Sunbelt Rentals rents that is made by edco or something like that but it has two heads and I was told they don't do well on uneven surfaces.