Help me out on Polyurea Install before I start.

[Corvette Dad]

So....I've got some Polyurea that I bought out of the classifieds section here. 4 gallons....I'll still need to order about another 5 or 6 gallons. My garage floor is about 750 sq. ft. and I plan to do my stem wall that is built out of concrete block.

For the floor prep, I have decided a shot blaster is the best option for me. I plan to use #330 shot and will either buy or rent an angle grinder to do the corners.

I plan to do the floor in sections, IE, the single car side, will be done and I'll stop at the expansion joints that I do NOT plan to fill. Then I can switch to the larger section of garage floor and do that. Before I do any of the floor, I will do the foundation wall. My thought is that I can do the block wall in a full day, then I can do 1/2 the garage one day and the other half the next day once the floor is prepped.

So, for planning purposes, how do I prep the block wall? It's already got a textured surface, so is it as simple as just cleaning it and then doing a tinted coat and the clear?

Any good, DIY'er, step-by-steps on the Polyurea install or threads on after thoughts. I've searched and can't find a ton of DIY stuff....it's mostly 3 minute long pro stuff.

What else am I not thinking of and need to prepare for?

 

[Shea]

So....I've got some Polyurea that I bought out of the classifieds section here. 4 gallons....I'll still need to order about another 5 or 6 gallons. My garage floor is about 750 sq. ft. and I plan to do my stem wall that is built out of concrete block.

For the floor prep, I have decided a shot blaster is the best option for me. I plan to use #330 shot and will either buy or rent an angle grinder to do the corners.

I plan to do the floor in sections, IE, the single car side, will be done and I'll stop at the expansion joints that I do NOT plan to fill. Then I can switch to the larger section of garage floor and do that. Before I do any of the floor, I will do the foundation wall. My thought is that I can do the block wall in a full day, then I can do 1/2 the garage one day and the other half the next day once the floor is prepped.

So, for planning purposes, how do I prep the block wall? It's already got a textured surface, so is it as simple as just cleaning it and then doing a tinted coat and the clear?

Any good, DIY'er, step-by-steps on the Polyurea install or threads on after thoughts. I've searched and can't find a ton of DIY stuff....it's mostly 3 minute long pro stuff.

What else am I not thinking of and need to prepare for?

Is there a specific reason you decided to shot blast? Shot blasting is typically not recommended for a DIY installation, particularly if one has limited experience with using a shot blaster. Also, because the hardness and density of concrete can vary across the surface, a shot blasted profile can vary in depth. This is why shot blasting is usually is reserved for high build coatings such as epoxy.

Have you checked the data sheets for the recommended CSP profile of the polyurea you plan to use? #330 shot creates a minimum CSP 3 profile. The reason I ask is that most DIY polyurea will not sufficiently self-level over a shot blasted surface.

As far as the block stem wall, just make sure it's clean. The polyurea will adhere well, but it may require two thinner coats to prevent runs. You won't be driving on the wall (hopefully ), so peeling will not be an issue.

 

[Corvette Dad]

Hey Shea -

Was going to go shot blasting mainly for the cleanliness factor. I don't really want to deal with all the dust and respiratory aggravation of renting the floor machine and diamond wheel from Home Depot. Acid Etch, I didn't want to run the risk of un-neutralized acid getting outside the garage and/or running off into the grass/flowers and killing anything. Came across shot blasting and it seems pretty tame. Messy, but with limited dust. No risk of acid getting somewhere I don't want it. Have watched several YouTube video's and it seems like the best of both worlds. You get the preferred surface prep of diamond wheel/grinding with the less mess of acid.

 

[Shea]

Etching usually provides a CSP-1 profile and grinding a CSP-2. A CSP-3 profile may be too aggressive for the polyurea. That is why I asked what the data sheets state. Shot blasting does not always turn out as easy as it looks in the videos either. It's too easy to make cornrows, create deeper pockets, and other irregularities that thinner coatings will not cover. That is why it's important to match up the coating with the recommended CSP profile. It's one of the primary reasons that most professional garage floor coating companies grind while using dust shields and proper HEPA vacuum equipment. They achieve specific control of the desired profile for the coatings used.

I'm just trying to make sure you are aware of all the things you need to consider before deciding to shot blast.

 

[Corvette Dad]

Product instructions say surface between CSP-1 and CSP-2.

Instructions say acid/grinding/shot blasting are all acceptable methods.

I appreciate the questions Shea - it's exactly what I needed to make sure I'm not missing something or getting in over my head.

 

[FJ4FUN]

Renting a proper twin head diamond grinder and HEPA dust extraction set up will get you the surface profile that you are after. Big Box store tool rental depts will usually have the Edco and a compatible HEPA vac available. We've also had excellent experience with SunBelt Rentals. When it comes to managing concrete dust the biggest offender is the angle grinder, finding a properly shrouded one at the local hardware store is difficult and the "universal" shrouds available are pretty weak and typically break down in short order.

As Shea has already mentioned, and I agree 100%, avoid shot blasting for your application.

 

[Armorpoxy]

We also would recommend staying away from a shot blaster. In the hands of a novice user it can leave significant 'lawnmower lines' that epoxy will not fill. Rent a grinder with a PROPER self cleaning vacuum and shroud and you will get a much better result.

 

[Corvette Dad]

Thank you. Shot blaster idea is officially dead.

 

[Armorpoxy]

Last suggestion, if you have problems finding a proper rental vac, buy an inexpensive 'Dust Deputy' online which acts as a pre-filter and will capture 90% of the dust which will keep your vac's filter from getting clogged up too soon. A standard shop vac can plug with grinding dust in five minutes so then it loses suction and you could end up with a huge dust cloud!

Also wear a proper particulate respirator...silica dust not good to ingest!

 

[mogandave]

The acid sounds scary, but it seems pretty easy to me. That said, I don't think it will remove any grease or paint.

 

[Armorpoxy]

Acid will do nothing to grease or a coating. Acid only etches bare concrete.

 

[Corvette Dad]

Luckily, the floor is 6 years old and has no stains or issues with it thus far.

 

[lukel99]

I rented a shot-blaster, did 10% of my floor, saw how badly I was pitting it and returned it. Wasted about $300. Ended up wet grinding and it turned out much better, but takes much, much longer. I spent about 10-12 hours grinding 960 sq ft and wish I had the time to take another full pass at the entire floor. This is with 4000 psi concrete, not sure how much compressive strength has to do with the amount of time it takes to get a good profile.

 

[Armorpoxy]

Thank you for confirming the problems with shotblasting a garage floor. Even in the hands of an experience operator, 'lawnmower lines' are common. Just delaying the movement for a second can cause pitting and uneveness in the floor with a coating will not fix. A shotblaster in the hands of a novice operator can really lead to problems we have seen.

We strongly recommend staying away from shotblasting a garage floor for this reason. Plus shotblasters don't get near the edges and corners easily if at all.