Just a minor issue and question.
I have an old driveway. The expansion joint materials between sections of driveway concrete slabs has deteriorated/rotted and washed away. Now the 1/2 inche gaps fill with dirt, leaves, and grow grass.
Does anyone have an idea as to how I could fill the joints to avoid collecting garbage and from growing weeds adn still maintain the function of an expansion joint?
I was thinking about tar. But roofing tar? Asphalt tar? and would that look odd or worse?
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Replies
If you google <expansion joint caulk> you'll see a variety of products to deal with the joints. SOP for the size crack you have is a backer rod topped with exterior-rated caulking, tooled smoothly. You first have to clean the joints well; compressed air is great for this.
The tarry substance you're contemplating would be a crap-catcher, for sure, and you REALLY don't want it on your shoe soles.
and you REALLY don't want it on your shoe soles.
LOL... Good advice, particularly the backer rod. Caulk without it sometimes doesn't cure, ever. Makes for gooey feet. I once had a pool client with that problem. It was a mess.PAHS Designer/Builder- Bury it!
tarry substance? Yes, I know. It would be a crap catcher and a pain on the shoes. That is why I asked. Roofing tar for sure would be a NO NO, it is pretty soft in the summer. So asphalt product? Maybe, but I will check out your idea! Never thought they actually had a product for such an occasion. Thanks again.
Do right, last year we put in some stonework for a landing and steps. The yard sold up some type of product that fills the wide gaps of the stones. It's like a soft grout, flexible yet able to stand up to the abuse of being walked on.
The stuff was very easy to use. It was so easy, I was skeptical that it would work. I followed the instructions, just like package and the guy told me: sprinkle the dry material on, filling the gaps up to the desired height. Sprinkle water till the material is wet. Don't disturb it till it cures....about one day.
I was pleasantly surprised at the look and the results. Over the winter, I noticed a few spots that didn't take the weather well and I have some left over stuff that I'll patch with.
It looks like grout, feels like soft putty.
In the bag, the stuff looks like cement or grout.
When I get up to that property, I'll find out the brand name.
Anyways, that's what I'd use on my driveway.
blue
Splinter (aka godess of Carhartts and battery cables) has you on the right track. Take careful note of the "no dust" advisory.
You want a urethane compond. Several are available at professional concrete supply houses. If you are anywhere near a big town that would have a concrete supply place you are better off than going to a big-box.
The professional-grade products turn into something that resembles a hockey puck in durability.
The importance of backer is; 1) This stuff is expensive 2) if you fill a deep joint it will sink when it cures 3) caulks are designed (dare I say engineered?) to function properly when they adhere on two surfaces, but not three. Adhesion to three surfaces causes failure. The foam backer rod makes that happen the way it's supposed to. Straight scoop from the manufacturers, folks. A little known fact, and no extra charge.
Another tip -- tape the edges of the joint before you caulk. The stuff can be messier than you think. And it does not clean up off of concrete worth cr#p.
3) caulks are designed (dare I say engineered?) to function properly when they adhere on two surfaces, but not three. Adhesion to three surfaces causes failure. The foam backer rod makes that happen the way it's supposed to.
Did you intend to say "designed....when they adhere to three surfaces, but not two"? Sounds like the backer rod is a third surface.
Backer rod will move with the bottom of the caulk. As the two adhereing surfaces move in/out, up/down or whatever direction the forces take them, the caulk should stretch or compress as needed. Since the backer rod is not adhered to either surface, only the bottom of the caulk joint, it will rise or fall as the caulk stretches or compresses.
Ever notice that some caulks say not for use on cracks greater than x/y" or deeper than x/y" ? Exceed either of those recommended limits and the caulk will likely fail because it is not formulated to stretch beyound that point at the recommended thickness. The use of backer rod also serves as the depth adjustment for the joint being caulked. Having that part as close to spec as possible is very important to the performance of the caulk, i.e. surviveability.
I have seen more caulk joints fail because someone just loaded a crack or joint up with caulking. The shear volume of caulk and the fact that it is bonded to both sides, all the way down, and the bottom of the joint doom it to failure, no matter what quality it is.
I once worked with a carpenter that called caulking an apprentices' "liquid scribe molding" or "carpenter in a tube" :-)
Dave
<<Did you intend to say "designed....when they adhere to three surfaces, but not two"? Sounds like the backer rod is a third surface.>>No.DaveRicheson explained the rest of it.Using backer rod makes all the difference of whether the joint will hold or not.
Home Depot sells a Sikka brand concrete joint caulk one qt. caulk tubes....but may not have backer rod in thick enough gauge for your expansion joints....
Backer rod if the crack goes through the slab,and if the crack is over about 1/2 " wide or 1" deep. Get SELF LEVELING caulk. This will flow into the crack and need no tooling. The reason you need backer rod is because it will flow completly out of the crack if there is a void. Go to a professional place and get polyurethane SL. You probably wont need the primer that they might try to sell you. Check rental places for this.
You be right.
Backer rod set from 1/4 to 3/8" deep in the clean, dry joint. Make sure each end of the joint is stopped with something. Pump in SL1 urethane sealant and let cure for 24 to 48 hrs. depending on temp.
Repeat the process in 15 years if needed.
I have done a mile or two of the stuff in the past 5 years. The SL1 is by far the best single package caulk I have used yet. There are some two package products that are better, but only sold in bulk, and you need extra equipment to mix, load and apply.
Dave
How does this work on a slope?
It can be a little tricky with SL1 on a slope. I have done a handicap ramp with SL1. It took 3 seperate applications to get all the way up the slope.
The ramp was between two brick walls. We did the side joints where the old expansion joints had rotted out. We started at the bottom, used a piece of backer rod sticking up as a dam, and went about a 1/3 of the way up with the first run. Second and third day we added the other thirds. It worked pretty well after we figured out that the actual finished joint can't be any more than 1/4" thick, and slightly less is better. We also got less saging when the temperatur went above 90 inthe afternoon and we got direct sunlight. The SL1 would skim over and start to set pretty quick then. Trying it in the cooler morning hours and shade produced a small pudlle at the bottom of the first two runs.
A better product for slopes and walls is a two package product, or a regular polyurethane caulk, that is not self leveling like the SL1. Both can be tooled with a margin trowel or jointing tool dipped in mineral spirits. We also learned a trick, from a tuckpointing contractor, to blend the joints into the masonary. Dust the joint with masonary sand using a wide piant brush. It will look like a motar joint after you are finished.
Dave
That confirms what i thought about the self-leveling aspects being too helpful in some situations. I' never used the self-leveling product you mention for cracks, only a similar one for patching...and whatever i was patching had better be level, i found out!