Hi,
I have several cracks in concrete driveway. Some of these I have filled repeatedly. Also, have joints where the foundation meets the concrete. I have used many different products from Lowe's and Home Depot...polymers, latex, Portland based, etc. I follow the directions on the products,but the cracks reopen, material washes out, the caulk, itself, cracks. Is there a good, long lasting, caulk that anyone would recommend for me? Also, would I use a different product to caulk the gap between the concrete drive and the house foundation?
Thanks!

 

Repost:

The important thing to remember is that you are constructing a specific type of engineered joint, not just pouring goop into a slot.

The design parameters are specific and demanding, and if done correctly you will have a joint that will last for 5-10 years. Done via the pour-the-goop-into-the-joint, it will probably not last a year.

Here it is in a nutshell:

Remove the existing expansion joint material which you have done.

Clean the joint like you would clean your kitchen table, using mechanical means, then water, then air.

For a pool area, prime the joint with the recommended primer.

Insert the proper sized backer rod to a depth of one half the width of the joint. For your 1-1/2x1-1/2 joint, you would be best off by using 2" round backer, and cutting it in half.

Fill the joint with the sealant, and tool to provide a concave profile on the surface that will match the underside profile formed by the backer rod.

Your design goal is to have 100% adhesion on the sides with an hourglass shaped slug of sealant, that has NO adhesion to the backer rod and proportions of 2x width to depth in the center.

This is the only way that the sealant can perform to design specifications. Preparation is the most important thing, and a lack of proper preparation is the cause of 99% of joint failures.

Good luck!

 

Thank you so much for your reply. That certainly details the "how-to" for expansion joints, and I assume that method works as well for a joint wide enough to pack with backer rod.

The gap where the concrete drive meets the foundation of the house is minimal- when the drive was poured, it was poured right up to the foundation- no joint. The gap originally wasn't there at all. The first time I filled it, it was so narrow, I had to force caulk in with the pad of my finger. Two years later, the gap widens a bit more, I scrape out the old caulk, blow with a compressor, fill again. Next year, caulk is cracked. Repeat.

The other "cracks" I am referring to are from frost heave. Those are also very narrow and not deep. I just want to keep them that way.

I really don't think it is my application, as I said, I do follow the directions. I just thought someone might give me an opinion of a better caulk that I might buy someplace other than the home centers. Thank you, again. Connie

 

Sonnoborn NP1, but if you do not do the prep correctly, it will not work much better than the cheapos. You have to increase the width of the joint to a minimum of 1/4" (3/8" is best) and depth 1/2" to 3/4", and make it the proper shape, or you will never create a flexible joint that will last.

 

Thank you again, Tscarborough! I'll make note of that name, and perhaps will need to use that product at some later date. I don't think I want to widen the gap to a quarter inch on a 24 foot stretch! (That's the width of the house where the concrete driveway abuts the house.) I appreciate your time. Connie

 

personally i like sika or silicone but its a tossup,,, nevertheless, if you don't follow his advise, no mtl'll work properly,,, mtl doesn't fail when its specific for the use AND the crk/jnt's properly prepp'd,,, just my opinion & i've done 1,000s of miles asphalt & conc.

btw, its NOT caulk,,, sealant's what's needed,,, if its not properly tool'd or the spec'd mtl width:height ratio's not follow'd, it'll fail long before the expected 7yr life.

 

Thanks,so-elitecrete. Now, please tell me...What is mtl? I searched the web for companies who sell the Sonnoborn product that tscarborough recommended- I found a Dow Corning contractor's concrete sealant that appears similar, but there are no suppliers in the area..at least not according to the Concrete Network, listed over there on our right.

Connie

 

mtl = material,,, for sonneborn, try here: http://www.sealantsandcoatings.com/p...fm?CSICode=118 - no financial interest, just a quik google.

Dow Corning has product in large tubes at any const supply house,,, don't use conc network - more geared towards consumers/h-o's/diy'ers - am fairly ignorant of what's post'd.

the absolute best sealant, imo, is polysulfide but nothing'll work if the conc's not prepp'd right or the sealant installed correctly.

 

so-elitecrete,
Thanks so much for the website!