SikaFlex Disappearing Into Control Joints

[Metallitubby]

The title can be a little misleading, but what are some of you "pre-filling" your 1/8" control joints with prior to using a product like SikaFlex? I started filling my control joints and noticed that the product just keeps sinking into the joint.

Do I:

1. Just keep filling the joints with Sika?
2. Use a backer product (note that I've only been able to find down to 1/4" foam rod.
3. Use something else soft and pliable like 1/16" or 1/8" nylon rope before filing the joints?

It appears that the joints are 2-3 inches deep in most places, which may require 20-30 tubes of Sika product. If this is what must be done, then so be it, but is there an alternative?

Thank you in advance!

 

[Toolfool]

You can push the 1/4" rod in, using a putty knife or drywall blade, to the depth you want. Then Sika.

 

[Metallitubby]

You can push the 1/4" rod in, using a putty knife or drywall blade, to the depth you want. Then Sika.

I thought about this, but didn't want to buy the roll of 1/4" just to find out it didn't compress enough.

 

[benwah]

Don't know what kind of floor you have or what you are doing, but backer rod and 100% solids epoxy joint filler works great. Is the floor already coated?

 

[Metallitubby]

Don't know what kind of floor you have or what you are doing, but backer rod and 100% solids epoxy joint filler works great. Is the floor already coated?

Sorry for not specifying.

- 8month old new build/new slab
- Polyurea coating already applied

and I've got 12 tubes of SikaFlex already with two tubes "wasted" already on one small section trying to backfill a lost cause. Lesson learned.

 

[LegacyIndustrial]

Backer rod. Go to the local store and get a small piece and do a test before you buy the whole roll.




Sent from my iPhone using Garage Journal

 

[rlitman]

I thought about this, but didn't want to buy the roll of 1/4" just to find out it didn't compress enough.

Worst case, you can slit the 1/4" roll in half with a razor.

 

[Metallitubby]

Backer rod. Go to the local store and get a small piece and do a test before you buy the whole roll.

Is this product normally sold at hardware stores "by the foot"? If so, then I have no problem trying it. Otherwise, the big box stores seemingly only sell it in 100ft sections (at only $10 mind-you).

 

[Metallitubby]

Worst case, you can slit the 1/4" roll in half with a razor.

I thought about this as well. I'm glad I'm not the only one who thinks like this.

 

[BillK]

Most of that foam backer rod will compress almost flat. If not then you should be able to find something that will work in the weatherstrip section at Home Depot.

 

[Shiftless]

1/4 inch foam backer rod will definitely compress easily into a 1/8 inch wide crack. Use a putty knife. Ace hardware sells 25 foot rolls if for some reason you want to try it out before taking the plunge.

 

[Metallitubby]

Ace hardware sells 25 foot rolls if for some reason you want to try it out before taking the plunge.

This is good information. Thank you!

 

[mobiledynamics]

U want to buy the correct size rod ...though. Not too compressed.

 

[Metallitubby]

U want to buy the correct size rod ...though. Not too compressed.

I haven't seen anything under 1/4", and I'd imagine that it would hard to push anything smaller into the joints.

 

[jollygreengiant]

I used 1/4 foam backer rod and pushed it into the joints with a screwdriver.

But before you do any more, use something else!

I put sikaflex down in my control joints last July after my floor was poured. It is now separating and cracking everywhere and looks like garbage.

 

[rlitman]

I used 1/4 foam backer rod and pushed it into the joints with a screwdriver.

But before you do any more, use something else!

I put sikaflex down in my control joints last July after my floor was poured. It is now separating and cracking everywhere and looks like garbage.

15 years ago, I put Sikaflex SL into the expansion joints (not control joints, so we're talking at least 1/2" wide) of my sidewalk, so I'd have less weeds to remove from cracks. 90% of what I applied is still holding up fine today, after all that time exposed to the elements.

What destroyed yours?

 

[jollygreengiant]

15 years ago, I put Sikaflex SL into the expansion joints (not control joints, so we're talking at least 1/2" wide) of my sidewalk, so I'd have less weeds to remove from cracks. 90% of what I applied is still holding up fine today, after all that time exposed to the elements.

What destroyed yours?

I haven't applied anything to my floor so it's not that it's reacted with something.

 

[mike93lx]

I thought about this, but didn't want to buy the roll of 1/4" just to find out it didn't compress enough.

You are considering buying 20-30 tubes of sikaflex but don't want to spend $3 to try some foam backer rod because it might not fit?

 

[Shea]

You can also use clean silica sand to fill the joint part way first if the backer rod does not want to cooperate.

 

[Metallitubby]

You are considering buying 20-30 tubes of sikaflex but don't want to spend $3 to try some foam backer rod because it might not fit?

"considering" is a loose use of the word. More like "had thought about what I would have to do to get the job complete".

Also keep in mind that 100% of the stores I've visited over the past month do NOT have 1/4" backer rod in stock. I went to two Ace locations, two Home Despots, and two Blowe's locations.

 

[mike93lx]

"considering" is a loose use of the word. More like "had thought about what I would have to do to get the job complete".

Also keep in mind that 100% of the stores I've visited over the past month do NOT have 1/4" backer rod in stock. I went to two Ace locations, two Home Despots, and two Blowe's locations.

https://www.amazon.com/dp/B000DZHF4Q/?tag=atomicindus08-20

It would be there tuesday

 

[Metallitubby]

It would be there tuesday

Gee, what would I ever do without you... and your condescending responses?

 

[mike93lx]

Gee, what would I ever do without you... and your condescending responses?

No sweat, happy to help

 

[Ak Jim]

Like someone above posted. I used sand. Seems to be doing fine after several years. I asked at the place that sold the Sikaflex and they recommended sand. I didn’t think of using backer rod.

 

[NUTTSGT]

Got any sill seal leftover from your build ?

 

[welder4956]

If you want to use rope or string, that will also work. Nothing magic about backer rod. It only needs to support the caulk till it dries. Just about anything that fits in the crack will work.

 

[Hammer]

If you decide to go the backer rod route a cutting wheel off of a hand grinder works well to push it in the crack

 

[Lonnies Performance]

I used the 1/4" rod without any issue.

I also used a tool made for putting in window screens.
It has a roller to push the rod it & worked very well for the $4 I spent on it.

https://www.lowes.com/pd/Saint-Gobain-ADFORS-8-in-Plastic-Screen-Rolling-Tool/3094501

I put in about 600ft of rod with one of these.

 

[rlitman]

I used the 1/4" rod without any issue.

I also used a tool made for putting in window screens.
It has a roller to push the rod it & worked very well for the $4 I spent on it.

https://www.lowes.com/pd/Saint-Gobain-ADFORS-8-in-Plastic-Screen-Rolling-Tool/3094501

I put in about 600ft of rod with one of these.

Now that's good thinking!

 

[dogdog]

I do my joints 4" deep so I don't have to deal with it for years... and I haven't have to deal with it for past 12 years.

Backerrods is the proper answer.. make shift a paint stick with a dowel drilled 4" or around 4" that will be your set stop to push the backerrod down to depth.

if you can't find backerrods and it was too expensive for me... I did have used these as a ghetto solution, and it worked fine, not as nice as backerrod

https://www.homedepot.com/p/Owens-C...ti-Use-Ridged-Sill-Plate-Gasket-2FS/202080947

Peal it in strips and twist them then stuff them down with the paint stick tool you just made. works. cheaper, but not as effective.

 

[Lonnies Performance]

You do not want the sealer 4" thick. That is a huge waste of money.

Proper ratio is 1/2 as deep as the width...
On an 1/8" width, you can't do a 1/16" depth, nor is under 1/4" deep recommended.
I went the depth of the tool I recommended, which was about 1/2"
4 years later, not one of them has split.

I did have some separation where my slabs joined, which were more like 1/2" wide tooled joints, but I sort of expected that on a floating joint.

 

[mobiledynamics]

I may be wrong on this but it was always my understanding the rod not only provided the correct shape but also the correct dept of the sealant for BEST longevity.

 

[rlitman]

I may be wrong on this but it was always my understanding the rod not only provided the correct shape but also the correct dept of the sealant for BEST longevity.

That's my understanding as well.

 

[Zmann]

I had the same and I used a cheaper caulking that had some body to it to prefill the lower crack in the radius trowed expansion joints

the saw cut relief joints I also had issues with did not allow for the caulk prefill
for those i found backer rod was too finicky to set to depth but I did have some thin wall tubing that fit perfectly and was easy to tap down 1/2 inch using a long flat stock

on the shop floor sawcut joints I overfilled a bit and trimmed with a flat scraper 5 days later ( stuff stays gooey for a long time)

the exterior slab radius joints I let itself level to 1/2 thick and sanded the top

 

[p00p]

https://www.amazon.com/dp/B08GX7RJTS/?tag=atomicindus08-20

stuff that in the crevice & inject the tubes on top.

 

[dogdog]

You do not want the sealer 4" thick. That is a huge waste of money.

Proper ratio is 1/2 as deep as the width...
On an 1/8" width, you can't do a 1/16" depth, nor is under 1/4" deep recommended.
I went the depth of the tool I recommended, which was about 1/2"
4 years later, not one of them has split.

I did have some separation where my slabs joined, which were more like 1/2" wide tooled joints, but I sort of expected that on a floating joint.

I may be wrong on this but it was always my understanding the rod not only provided the correct shape but also the correct dept of the sealant for BEST longevity.

That's my understanding as well.

Not sure, All I can say is the "other" neighbors that did the sealant and use the that ratio... their stuff lasted about 2 winters on outside sidewalk..

doesn't matter... you can still do the same, make a stop stick at 1" and push it down to set the depth.

hmmm... indoor floor might be different.

 

[Steve in UT]

I've been thinking about using tile grout and sealer to fill my saw cuts. Anyone see a problem or why that wouldn't work? It just seems like it would be so much easier and less grief getting it even with the floor. Cheaper too!

 

[benwah]

I've been thinking about using tile grout and sealer to fill my saw cuts. Anyone see a problem or why that wouldn't work? It just seems like it would be so much easier and less grief getting it even with the floor. Cheaper too!

I've never used tile grout, but have used waterborne epoxy grout. It's essentially the same texture, but epoxy. Tape your joints with Frog Tape, 1/16" back from the joint on both sides. Burnish the tape with your finger so it has a tight seal. Use a 1-1/2" plastic flexible putty knife to apply.

Get you a buddy or two, a case of beer, a couple large sponges and some buckets of clean water. Once the epoxy grout starts setting up, wipe clean until you're satisfied. Works best over an already sealed floor, or else the grout will be absorbed into the unsealed concrete.

 

[Armorpoxy]

Hi, how much lineal footage do you need? We may have some 1/4? backer foam in our warehouse. If we do we will send n/c. Please email not PM.

Alternately we have recommend the use of sand to support joint filler. Pour in sand and run a screwdriver or similar tool or cut up an old can to make a tool which leaves about 3/8" depth so the filler has support.