Seam in Garage floor
 

Not sure how to word or ask this, but here goes:

The garage floor has 4 sections to it, with a "seam" running vertically and horizontally across the middle. This seam (or crack) is quite wide (1/2 to 3/4") and not filled in with caulk or anything.

My question, should it be filled in, it's getting a lot of dirt and other debris in it. Eventually I plan to have the floor painted but right now the garage is still filled with boxes and other junk.

Mine were just a saw cut (1/4 inch wide), and I bought a grey silicone seal and used that to keep the dust and dirt out, has been in place for over a year, and seems to be working. This material is available at Home Depot, Lowes, Ace hardware, etc.
Hope this helps.

If your seams are really that wide, something has settled a lot. The garage floor is poured as one solid piece of concrete. Than after about 12 hours they use a concrete saw to cut those seams to prevent cracking. So they started out the width of a saw blade probably around 1/8 of an inch wide. You may get some settling and they open up some, but if they are 1/2 inch or more there is a problem. If a new house call warranty, if an older home might want to get someone in to check the structural integrity of your foundation.

As others have already posted, these are the relief cuts made in hopes that by putting a cut in the concrete that makes a specific area where the concrete is weaker, thus increasing the chance that the concrete will pick this "seam" to crack. Most of the time the concrete will crack at it's weakest place, which would be where the relief cut is. One should have relief cuts for every 100 sq ft approximately.

This does not always work out this way, and concrete could crack anywhere.

Some folks will caulk this crack, especially near where it meets the garage door to minimize chance of pest intrusion. You can easily do this just under the door without doing all of the relief cut if all you care about is bugs getting in this crack.

If you do caulk this "seam" I would be leery of using 100% silicone, as if you down the road want to paint the floor or apply epoxy it will not adhere well to silicone. I suggest applying a more expensive two part epoxy resin product making sure it is flush with the floor. Then if you do paint or epoxy coat later you will not be able to even tell where the relief cuts are.

Understand that most folks never do this. There is no harm of leaving them as is. You can blow out or vacuum these cuts every so often to keep them clean.

I am assuming that you were exaggerating about the width. As previous posters have stated if that relief cut IS really that wide, you may have more serious issues that will need attention.

Hope that helps...Frank D.

Frank,
Thank you for your excellent advice, I should have clarified my reply, I had already coated my garage floor, and the silicone sealant actually matches the coating very closely. Frank is correct, if you intend to paint/stain/epoxy the garage, use a suitable product.

We had an unattractive crack where the relief cut was made. I got some concrete repair in a small tub, applied it down the crack, then smoothed it with a finger (wearing gloves). I did it because of its appearance. Looks much better now, with no debris collecting.

Sonaborn NP1 or SL1 this is a caulk that is specifialy designed for concrete there is nothing better, Local 11,Cement Masons,retired

I would be careful about filling the cuts with a non-compressible material, because the slabs do expand and contract with temperature changes. If the cuts are filled solid, their purpose is defeated. Handyman has the ideal solution for sure. One possible alternative might be to stuff the cut with a foam backer sized correctly, and finish with a surface leveler.

Thank you handyman....that is great info. I will research it. I agree with mulligan and should have mentioned about slab movement. This is one of the best things about TOTV, good people helping neighbors and all of us learning as a result.

Respectfully, Frank

I should have checked TOTV before i "fixed" my seam!

Thank you all, great advice and I feel much more calm (unless of course it's structural?) Mulligan, what's a surface leveler?
Handyman, does Sonaborn allow the concrete to expand with the temperature?

A surface leveler is a portland cement product meant to be applied in a thin layer(usually 1/8" or less) to straighten minor defects in a concrete slab.

After reading the spec sheets on both the Sonaborn NP1 and the Sonaborn SL1 both allow the concrete to expand/contract, but the SL1 is a self leveling product. Handyman since he has vast experience with this product beyond just reading the spec sheets he might explain it better, but here are both....

http://www.bestmaterials.com/PDF_Files/np1_tdg.PDF

http://bestmaterials.com/PDF_Files/n...-datasheet.pdf

Looks like both are quality products. Note that because the SL1 is self leveling, for very deep cracking a foam backer may be needed. This is why they make both the NP1 and the SL1

Hope this helps...

When you say foam backer, does that mean stick a piece of foam (or is it in a spray can) in the crack before applying the product? Sorry, this is all new to me, learning as I go.

Generally, you would use a strip of foam that would fit in the slot, and below the top surface, I would say at least 1/4 inch below the top. If you try to use spray foam, this is designed to expand, and it will completely fill (probably over fill) the slot, leaving you with a mess to dig out enough to put in the filler.
Anticipating your next question, I have seen foam at the craft stores, like Michael's, it is sold in sheets, so you will need to by the thinnest foam you can find, and use sissors or a very sharp knife to cut into strips.
Hope this helps.