Option 3 is Trim-A-Slab, and the cost as of August 2013 is $2.49/ft for the size that replaces 1x4"s. Smaller sizes are cheaper, larger sizes cost more (up to 2x4 size).
Using spray foam insulation does what backer rod and even playground sand does - it limits the amount of sealant being used, primarily because the sealant is expensive. A 3/4" wide x 3/4" thick bead of sealant will cost as much as Trim-A-Slab 3/4" size, on a per foot basis (still $2.49/ft in the spring of 2018). The press-in, elastic sealers like Trim-A-Slab will be much quicker to install; you will finish in the time it takes to install just the backer rod. You can also drive on them right away, and peel them out annually to run your extension cords for holiday decorations. The liquid sealers will have to be used if you are filling jagged cracks, however. The press-in elastic seals are good for expansion joints which were originally wood, fiberboard or saw cuts.
YOU CAN NOT USE SPRAY FOAM OR SAND OR ANYTHING BUT BACKER ROD UNDER SEALANT IF YOU WANT THE SEALANT TO LAST. You absolutely HAVE to use backer rod. Things like this is why sealant has to be redone so often. When properly installed sealant will last 20 years or more.
You don’t necessarily have to use Sika, Vulkem and master seal both make quality self leveling sealant too. ( I have installed many miles of flat work sealants).But you are absolutely correct.
Both caulk and the rubber-like sealers will do a better job at keeping water out than wood. A perfect seal is not really required, though. The soil beneath the slab can get wet, but better not get washed away, as that will leave the slab unsupported. Take away the support,and the weight of your car will crack the slab.
yeah I'd use the backer rod just to eat up space and keep cost down and pour in some grout and then take a demo saw and cut a relief cut on either side.
Very bad idea. These are called “ expansion joints” for a reason. They allow the slab to move, hopefully without cracking. Putting non shrink grout defeats the purpose and will cause cracking eventually.
@@genecarden780 hey I had a question. My concrete joints won't allow backer rod to go far enough down because inside where the concrete cracked there are still edges on the crack. Do you think its fine to just fill without backer rod or should I take an angle grinder or chisel and break those crack sides off in the joint so I can get enough room for the backer rod
Wood seems like an extraordinarily bad choice for an expansion joint. Not only will it rot but isn't the point of an expansion joint to expand & contract with the temperature changes?
I have seen individuals use the low build window and door insulation foam in the crack, leaving the 3/8 in or so depth and topping that with the regular seal such as sika it seems to work well and be cheaper than the backer rod method. Prep would be the same.
You HAVE to use the proper sized backer rod. Period. Cutting basic corners like this is why sealant has to be replaced so often. Properly installed sealant WITH BACKER ROD should last about 20 years.
Dirt and sand can be used, but they won't necessarily stay in the gaps unless covered, and if not covered, will obviously be a place where weeds will grow. To prevent weeds, you either pull them out, or spray something like Roundup, which will inevitably wash into storm drains, and get into the local watershed. These chemicals may be toxic to aquatic life (en.wikipedia.org/wiki/Glyphosate), and debate is still ongoing whether or not glyphosates are carcinogenic. Covering with a cure-in place liquid sealer requires that the concrete you are bonding to be clean, and free of dirt. This will be tricky if you have just filled these gaps with dirt. If the sealant is not bonded well to the concrete, it will pull away from the slab edges, and you are back to the weed control condition. You will also have to do this in good weather, and keep kids, pets, and wind-blown debris out until the stuff cures. The cost per foot will be a wash if the sealant is about 3/4" deep, in a 3/4" wide gap, so there will be no cost savings unless the coating is thinner than that. The lower cost option of using a thin coating of sealant will just take more effort to make it effective and look nice. Yes, it is possible, but not everyone has the time or skill to make that work for them. That's the choice that is offered by Trim-A-Slab.
Backer rod will stay playable and will not absorb moisture. That eliminates two of the main contributing factors to joint sealant failure. There are good reasons why professionals use it.
@@badlandskidYou are forgetting backer rod also provides another essential function. It gives the sealant the proper profile. Absolutely necessary for the proper functioning of the sealant
@@genecarden780 I didn’t forget. I chose not to mention it because the average person isn’t going to be cognizant of how sealants perform symmetrically verses asymmetrical. And they likely won’t care
