Question on Filling Cracks

[Hawkins]

So I was looking at undertaking a garage project to epoxy my floors (finally after a year of research). I have a 4 car with a decent amount to do...plus have an area between house foundation and garage floor on edges which need filled.

My question is two part:
1) I've watched a lot of videos and it seems like people grind the floors first, fill the cracks/control joints, then grind the areas where they filled. Is there a reason for this? To me it would seem easier to fill cracks/voids first, then grind entire floor, then apply more crack/joint filler if a new crack opened up?

1a) Any recommended joint filler. Note that my floor only has a couple hairline cracks but has a decent amount of control joints just because of the area. I dont have exact liner foot but not sure what best bang for buck is but would have decent amount when factoring in doing the seam between foundation and garage floor. I know there's some gel, there's some where you put sand in then squirt with a poly, some caulk-like, etc. What works best?

2) What is best degreaser to use. Floor is 3 years old and doesn't have a ton of oil-based stains but I do have a "larger" spot where chainsaw oil leaked on the floor. I tried "Pour N Restore" and got bad results. Should I do an overall floor degreaser prior to the project and focus heavily on the spot -- or just focus on the spot without doing overall degreaser.

3) Tagging on Grinding Questions -- I plan to Wet Grind since I don't have the appropriate vacumn to dry grind. Would it be appropriate to wash the floor with a pressure water (or a hose) after finishing the wet grind? I know floor has to be dry prior to the primer coat going on but how long can a ground floor sit prior to apply the first primer coat? This is in case I can't get to the floor for like 2 weeks after the grinding is finished and just want to clean off any dirt/debris between grinding and coating.

Thanks for your help!!!

 

[Shea]

1) If you are grinding with diamond impregnated discs or a turbo cup wheel, then most repairs and fills can be done first and ground flush as you go. However, if you are using a wheel with flexible blades such as the Diamabrush, then you will need to grind the repairs and fills separately. The reason is that the flexible blades tend to follow the contours of the concrete and don't cut across them well.

1a) I suggest you read the article in the link below. It explains what types of filler to use for what type of joint.

How to Fill Expansion and Contraction Joints in a Garage Floor | All Garage Floors

We discuss the proper sealer and filler to use for each joint type. This includes how to fill garage floor joints to achieve a seamless garage floor coating.

allgaragefloors.com

2) Purple Power is known to work well. If most of the floor is fairly clean, then there is no need to degrease first. Just focus on the spot.

3) DO NOT WAIT to rinse the floor clean if grinding wet and do not let any part of the concrete that was ground and not rinsed yet start to dry. The slurry will settle into the pores and is a real B**** to get out and get clean. Grind in sections and rinse in sections as you go. You will have quite the mess on the driveway.

 

[Hawkins]

1) If you are grinding with diamond impregnated discs or a turbo cup wheel, then most repairs and fills can be done first and ground flush as you go. However, if you are using a wheel with flexible blades such as the Diamabrush, then you will need to grind the repairs and fills separately. The reason is that the flexible blades tend to follow the contours of the concrete and don't cut across them well.

1a) I suggest you read the article in the link below. It explains what types of filler to use for what type of joint.

How to Fill Expansion and Contraction Joints in a Garage Floor | All Garage Floors

We discuss the proper sealer and filler to use for each joint type. This includes how to fill garage floor joints to achieve a seamless garage floor coating.

allgaragefloors.com

2) Purple Power is known to work well. If most of the floor is fairly clean, then there is no need to degrease first. Just focus on the spot.

3) DO NOT WAIT to rinse the floor clean if grinding wet and do not let any part of the concrete that was ground and not rinsed yet start to dry. The slurry will settle into the pores and is a real B**** to get out and get clean. Grind in sections and rinse in sections as you go. You will have quite the mess on the driveway.

1) Thanks. I am using these from the rental company. I think they may be diamabursh but not sure: https://artsrental.com/products/diamond-grinding-dots-for-floor-grinder-6-each

1a) Thanks for the article. I've just read it and very helpful re: the flexible stuff. I think i found my product

2) I'll look to buy this.

3) Thanks for tips on this. I realized there would be a slurry but didn't think about the cleanup of that. And the fact that concrete slurry is considered "toxic waste" (I think). While I realize my original question wasn't necessarily clear, your response is very valuable. To rephrase my original question, I plan to grind the floors one weekend, then I think I may have to wait 2 weeks or so to apply product. I plan to keep usage at a minimum; however, is a wait a dealbreaker? Of course, i'd have to re-wash/clean floor if debris is picked up but not sure what thoughts are on this.

 

[SolarColumbia]

I didn't want to park outside overnight so I put cardboard down anywhere the car tires would touch the concrete to prevent oil, etc getting on the floor from the tires or from dripping off my Jeep's valve cover . If it's rainy you can use plastic sheeting. During the day I parked outside and removed the cardboard. You want to let the concrete dry for a few days. Once I was ready to coat I gave the floor a good sweeping to remove any dust, etc.

 

[Shea]

Just keep it clean and dry and you will be fine.

 

[Armorpoxy]

A comment on filling joints (not cracks) is that we recommend filling them after the epoxy is down for the reason that control joints are there for a reason so if/when the slabs move and you have filled the joints and epoxied over them, then your inflexible epoxy will develop cracks along the joint lines.

For this reason we normally recommend either not filling them at all and leaving be, or filling them after with a color-coordinated joint filler. Sikaflex available at home centers has a colors or a company called Metzger & Mcquire makes a joint filler in about 100 colors, it's called RS-88.