Caulking Expansion Joints

[brone1]

Does anyone have a good way of caulking expansion joints. I will be doing this after the epoxy and clear is applied. Just want to do it as clean as possible and have it level with the concrete floor. The joints are 1/4 inch saw cuts.
Thanks,
Brian

 

[mhoffm911]

I am looking for this also. Lowes has tubes of product from Sika Corporation that are supposed to be self leveling. The box they come in depicts a guy doing this exact project. It looks like you put it in with a caulking gun and then it levels out. I'm about a week away from doing mine, so looking forward to other replies.

http://www.sikaconstruction.com/con/con-repair.htm

 

[PAToyota]

The one secret is expansion joint backer rod - a foam rod that is placed in the joint before the caulk is applied. This allows the caulk to seal to the two sides - and not the back/bottom - of the joint and allow movement. If movement is not allowed, the caulk will pull away from one or both sides and not seal properly.

 

[Steve in Mi]

I had about 125' of ~1/4" X 1-1/2" saw cut to fill in my shop floor and decided that would be a BUNCH of caulk to buy if going that route.

BTW, to those that will be cutting for control of stress cracks use as narrow a saw cut as possible in your floor.

I filled the cut lines with mortar, mixing it right in the crack until it filled flush with the floor. It will shrink some and be slightly concave when it dries. I plan to use a clear sealer throughout (only 25% is sealed so far) so I needed to avoid getting any mismatch in color on the floor surface from filling. I first wet the crack with a water from a large syringe, next, introduced the dry mortar thru a flattened (slit) funnel, adding more water with the syringe as necessary and mixing with vertical strokes of a putty knife to accomplish this. Once the mortar started to set/dry I kept it damp for a few days along with the cement on each side of the cut line. It came out okay but a thinner cut would have been best all around. When rolling tool carts etc. over the wider cuts the steel wheels tend to break off the edges. Both filling the cuts and applying the clear acrylic sealer have reduced this tendency.

I think (but really don't know for sure) filling the cut lines before putting down your epoxy might give you a better chance of keeping the edges of your cut lines intact, particularly if the filler is relatively hard. If you use a soft material for the filler my guess is the edges will abrade/break off. Someone with actual epoxy experience will know better what works best.

 

[PAToyota]

As Steve brings up above, there is a difference between a sawcut control joint and an expansion joint...

 

[mhoffm911]

Where do you get the backer rod? Will the guys at Lowes or Home Depot know what I am talking about?

 

[boiler7904]

Lowes and Home Depot both carry it. Make sure you buy a size larger than the joint you're trying to fill i.e. use a 1/2" backer rod to fill gaps between 1/4" and 3/8". You want the foam to compress so that it is friction fit.

The other thing that I would recommend is to pick up some 1" blue painters tape for new / delicate surfaces - usually has an orange core. Run a strip down each side of the joint as straight as possible. Remove it immediately after applying and tooling the caulk. Your joints will look a lot better and you won't have to clean up eroneous caulk from your new floor.

 

[PoorOwner]

Backrod is sold at lowes near the weather striping.

My garage is old and the expansion joints were felt or some kind of fiberous material, I dug it all out. The joints were almost 1" wide in some cases, I stuffed it with backerod if needed and just used silicone caulk (GE XST?)

1/4" I would consider filling with caulk and putting the epoxy over it though.
Use latex caulking because they are paintable, I did this for the cracks on the slabs BEFORE epoxy. The problem with the latex caulk is that will shrink a bit over time, but it held up well. That was before I knew about GE XST paintable silicone, I imagine you will get less shrinkage with that. But sounds like you can use masking tape in your application and do a very clean job.

The sika product is very good and seems more suitable for wider joints than 1/4", they are costly tho, that's what I SHOULD have used because no matter how much you tool a 1" wide gap of silicone, it doesn't look very good.

 

[POR-15 Chris]

POR-15 has a Flexable seam sealer Called POR Patch It will do fine in this type of application.

 

[mhoffm911]

I spoke with Rustoleum tech today. She said that the Sika sealer would not let their product adhere. Basically, you need a concrete or epoxy based product for their Epoxyshield to adhere to.

This ticks me off because I just used Quikrete patch/sealer on about 50 spots in my floor - she says I have to grind them off now.

I found the backer rod at Home Depot and bought the tube sealer (which I am going to have to take back now).

Any other recommendations??

 

[KELLHAMMER]

Pool supply stores carry caulking to do gaps up to 3/4". Backer-rod is available also thru masonry supply company's. The kind that deal with contractors. Sika has a good website that explains how to caulk properly

 

[SteveL]

I spoke with Rustoleum tech today. She said that the Sika sealer would not let their product adhere. Basically, you need a concrete or epoxy based product for their Epoxyshield to adhere to.

This ticks me off because I just used Quikrete patch/sealer on about 50 spots in my floor - she says I have to grind them off now.

I found the backer rod at Home Depot and bought the tube sealer (which I am going to have to take back now).

Any other recommendations??

I'm curious why they say the Quikrete patch/sealer won't work???? Is it not a concrete based product? I can see not using a water based product but Quikrete stuff is supposed to be concrete/motar based as far as I know.

Also, will the POR15 seam sealer work with a two part epoxy product?