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Forum topic by leftcoaster posted 02-02-2020 12:07 AM 672 views 0 times favorited 16 replies Add to Favorites Watch
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leftcoaster

360 posts in 1762 days


02-02-2020 12:07 AM

My shop has a concrete floor which has four “parts” that are divided by what I think is called an expansion joint. It’s one slab but there are 1/2” wide joints that are supposed to be where the cracks happen with contraction.

What kind of product should I use to fill these joints for a smoother ride with machinery on casters? The joints still need to perform their function!

Candidates I know of – concrete caulking. “Crack sticks” and various kinds of grout.


16 replies so far

View Scap's profile

Scap

131 posts in 812 days


#1 posted 02-02-2020 12:39 AM

Try looking at a product called “Slab Gasket”. It may work for your application.

View bandit571's profile

bandit571

26736 posts in 3569 days


#2 posted 02-02-2020 12:55 AM

Actually called a Control Joint. We used to just mix up a batch of drywall mud. Later, we had a contractor come in with a foam gasket and epoxy….for the open joints between the slabs on tilt up walls we were building.

-- A Planer? I'M the planer, this is what I use

View CaptainKlutz's profile

CaptainKlutz

3733 posts in 2380 days


#3 posted 02-02-2020 01:25 AM

Those grooves are bane on my wood working existence! X^%@#$%^&%&@&^([email protected]!!!
Thanks, now I feel better.
Not really. ;)

Those cracks destroy small casters:
Dust Collector rubber wheels:

Shop Fox mobile base:

One solution I find works: Bigger casters!
Dump the wimpy 3” OD stuff and use nothing less than 4” OD.

Hate to recommend anything Rockler, but the All Terrain Base is only commercial base with large enough wheels to get over those [email protected]$%^&(@! cracks.

Flexible crack filler is expensive. Have lived in 4 different homes in last 7 years, and larger casters was cheaper solution than filling in [email protected]$%^&(@! driveway and garage cracks added to every house to meet local building code.

Hate those [email protected]$%^&(@! cracks!!

YMMV

PS – Sorry to be so passionate about control joints. But have all I see is RED when they are mentioned.

-- If it wasn't for bad luck, I wouldn't have no luck at all, - Albert King - Born Under a Bad Sign released 1967

View therealSteveN's profile

therealSteveN

6473 posts in 1459 days


#4 posted 02-02-2020 03:56 AM

Klutz, chilll…...... 4” casters or larger, and the problem goes away, well maybe a slight ga-dump as you go over them.

They do kind of make you buy a better grade of casters though.

There is a plus side to this conversation. If you didn’t have them to begin with, it would mean you are working out of a 8×8 floor plan, and wondering how to get anything done…..

-- Think safe, be safe

View Snipes's profile

Snipes

459 posts in 3130 days


#5 posted 02-02-2020 03:01 PM

Epoxy

-- if it is to be it is up to me

View j1440's profile

j1440

21 posts in 605 days


#6 posted 02-02-2020 03:14 PM

I filled my groves about two years ago with “Quick-crete” that I got at Home Depot.
So far it has held up great.

-- Jim, Kingman, Az

View gmc's profile

gmc

75 posts in 3042 days


#7 posted 02-02-2020 05:04 PM

You are supposed to use a self leveling joint compound on these joints. If you fill them with epoxy you defeat their purpose. Here is one of many on the market you can use;
https://www.lowes.com/pd/Sika-29-oz-Gray-Self-Leveling-Sealant/999977080

Since my son is a concrete finisher, he told me this was the best way to level out the joint and fix the problems with pushing machines across them. It worked fine for me and I don’t have everything on 4” wheels. Hope this helps.

-- Gary, Central Illinois

View Snipes's profile

Snipes

459 posts in 3130 days


#8 posted 02-02-2020 05:52 PM

“You are supposed to use a self leveling joint compound on these joints. If you fill them with epoxy you defeat their purpose”

Well unless this shop is like 300’ long you don’t need any expansion joints. Control joints yes. Epoxy would work great.

-- if it is to be it is up to me

View LesB's profile

LesB

2627 posts in 4328 days


#9 posted 02-02-2020 06:16 PM

There are two types of “joints” in concrete slabs. One is expansion joints that go all the way through from top to bottom and they are often filled with an flexible material that divides large spans of concrete into smaller sections so they can expand and contract without buckling. The other are crack control joints which as the name implies control or direct any cracking along shallow recessed grooves intentionally made in the slab….other wise you have those zig zag cracks. When the contractor poured the slab for my shop they were not going to add the control grooves but at my insistence them did. That was 25 years ago and today the only cracking I have is along those control grooves.

There are a number of concrete crack fillers available. For cracks in a garage floor I have successfully used one of the semi flexible types which should also work in your situation. I don’t recall the specific brand but it came in a can (cheaper then the tube type) and I applied it with a putty knife. I would not recommend a hard filler because the concrete will continue to move and only pop the filler or cause it to crumble….dry wall mud is quite soft and will not stand up well either.

-- Les B, Oregon

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LesB

2627 posts in 4328 days


#10 posted 02-02-2020 06:18 PM

error

-- Les B, Oregon

View Snipes's profile

Snipes

459 posts in 3130 days


#11 posted 02-02-2020 09:41 PM

Not sure how big this shop is but if your going to use a tube of caulk to fill a half inch gap your going to need a lot of tubes.

-- if it is to be it is up to me

View leftcoaster's profile

leftcoaster

360 posts in 1762 days


#12 posted 02-02-2020 09:44 PM

Thanks all – I only have 20 feet of joint to fill. Looks like this

View cowboyup3371's profile

cowboyup3371

173 posts in 1083 days


#13 posted 02-02-2020 10:10 PM

View bandit571's profile

bandit571

26736 posts in 3569 days


#14 posted 02-02-2020 10:42 PM

Ok…there are 2 ways to do a control joint….float it in like above…or…saw the joint.

sawn in…casters will barely feel them….and usually fill up after the first couple times you sweep the floor…( usually 1/8” wide kerf, depending on the saw. We would seal it, then, if we were “casting” tilt up walls on the slab, we’d dry wall mud the kerfs, instead of going over the finished walls, sanding down the ridges left by the saw kerf. )

OP’s… was “floated” in….(pita to do, too) Epoxy to fill. You can use the quickrete stuff…IF you add the latex adhesive to the mix….BTDT….

Expansion joints: foam ( indoors) Asphaltic ( outdoors) Landscapers would use a treated board in the walkways….and, without a rebar dowels in the joint…..slabs will heave and settle without bother their neighboring slabs. And, yes they still will rot.

-- A Planer? I'M the planer, this is what I use

View teetomterrific's profile

teetomterrific

107 posts in 1247 days


#15 posted 02-03-2020 01:57 AM

Self Leveling Concrete Polyurethane Sealant

Self-leveling, weatherproof, resilient polyurethane formula Designed for joints/cracks in concrete floors

-- Tom, Adams, TN

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