control joints

[hoffman912]

so i had a new pad poured this fall, and i am starting to do research on what to do in spring when i paint it in rust bullet.

My pad did not have saw cut joints but the kind where they make a V shape trowl edge across the floor, dividing it in 4ths. I am assuming that is a control joint (correct me if there is another term for it). pad is 17x25.

OK, enough rambling and on to the question: Should i fill those in, or is it bad to fill it in? I like the idea of a floor i can roll across with out falling in a joint, but i dont want to hurt the pad if that needs to remain for expansion/contraction.

If it is OK to fill in, what should i use?

 

[streetdaddy]

Legacy ind. crack filler for sure. Easy to use and works great!

 

[Ch3No2]

I waited a year and filled them and sanded smooth with Ardex Feather Finish

 

[DC73]

I used this on my control joints before I put down the Rust Bullet:

http://www.homedepot.com/p/Rust-Ole...oncrete-Patch-and-Repair-Kit-215173/202097324

Put it down in early October. So far so good.

DC

 

[hoffman912]

Thanks guys. Does this defeat the purpose of having a control joint? Is patching it 4-6 mos after the pad is poured too soon? Is one product preferred over others?

 

[Shea]

Those are contraction joints. Here's an article that explains the difference between contraction and expansion joints as well as what type of filler is best to use for each one and why.

If you are going to apply the Rust Bullet over the joint, you don't want to use material that can crack if the joint moves. If you do, then the crack will carry on right through the coating.

 

[hoffman912]

So would you not recommend filling it then?

 

[boobag]

i wouldnt fill and grind the cracks, because the slab will move some over time. then the crack will reappear and show through the epoxy and look worse in my opinion.

 

[SunsetsAndFriends]

So would you not recommend filling it then?

One option is to prepare the concrete surface for coating but not filling/grinding the joints. After the epoxy is applied and cured, then fill in the joints with a good quality flexible caulking material, such as from Sika. The caulking could be selected to color match the epoxy.

This would give you the filled joints but with a flexible product in the case there is movement.

 

[Ch3No2]

i wouldnt fill and grind the cracks, because the slab will move some over time. then the crack will reappear and show through the epoxy and look worse in my opinion.

My initial post said wait a year before filling and grinding...at the bottom of the joint a crack did appear during that year. I then filled it and ground it smooth, epoxy and no cracks in 4 years.
This is my 3rd Garage floor with Ardex Feather Finish and not one failure.

 

[machsnell]

Ardex makes excellent products for sure. We use it to treat chips and scrapes in concrete flatwork all the time.

I wouldn't have imagined it working well on control joints over time but good to know. I don't think it has any flexibility but is strictly a mortar like. Nice work on taping it off.

I will use one of the flexible filler from legacy just to be safe when the time comes just to allow for slight movement.

Sent from my SM-G900V using Tapatalk

 

[LegacyIndustrial]

I will use one of the flexible filler from legacy just to be safe when the time comes just to allow for slight movement.

 

[DC_Gearhead]

One option is to prepare the concrete surface for coating but not filling/grinding the joints. After the epoxy is applied and cured, then fill in the joints with a good quality flexible caulking material, such as from Sika. The caulking could be selected to color match the epoxy.

This would give you the filled joints but with a flexible product in the case there is movement.

I agree.