Best caulk for concrete surface cracks, Silicon????

Discussion in 'The Duck Hunters Forum' started by Bands rule, Jun 6, 2011.

  1. Bands rule

    Bands rule Banned

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    I have been using silicon to go over the small cracks in my concrete driveway. Seems like it last about 2 -3 years then I power wash them off and re-apply.

    Anything better I should try?
     
  2. Jsw

    Jsw Refuge Member

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    Sika flex is about the best I've used just make sure it's not the self leveling kind. And if there deep I would use foam rope and push it down into the crack first hope this helps.
     
  3. WoodieSC

    WoodieSC North/South Carolina Flyway Forum Moderator Flyway Manager

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    What's the problem with the self-leveling kind of caulk? :scratch
     
  4. h2ofwlr

    h2ofwlr Elite Refuge Member

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    It can "run" (slag downhill) over the surface easier if there is a pitch on the drive way.

    But being it is runnier, it can also flow down into the cracks better.

    So disdavantages and advantages.

    Myself I like Polyurethane caulking.

    BTW--the concrete MUST be completely dry and no dirt/dust to interfear with the bond of the caulking to concrete for it to be effective on whatever oil based (polyurethane) caulk that you use. Most water based caulks can tolerate dampness, but IMO are not as good (durability) of a cualking.
     
  5. Jsw

    Jsw Refuge Member

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    You can use self leveling if you put the foam rope in if not it will take 300 tubes cause it will flow down the crack and fill any void under the slab. Sika flex is made for this kind of application that's all I've ever used in concrete parking lots and cracks, most any gas station that has the saw cut control joints has sika flex. Even an 1/16 inch hole will sink down and you'll have to keep putting more and wasting the product.
     
  6. TEAMGTG

    TEAMGTG Senior Refuge Member

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    Sikaflex 2c NS is what we use for the repair of concrete ditches and it works awesome under full submersion, and I have it in all the expansion joints in my driveway, and the gap between my foundation and perimeter sidewalks on my home. It's really great stuff, and its a good decoy fix as well. You can also get away with the Sikaflex they sell at Lowes and Home Depot #106711, but this product is self-leveling and as mentioned it will run if you apply it above 65 degrees on any type of grade. IF you apply it below 65, many times you can apply it on a pretty good angle, and it will not follow the crack and pool. As with anything else in concrete for the best adhesion use a bit of muratic or citric acid, and powerwash the joints before application. Being that silicone was in the joints I don't see that you would get very great grab at all without mechanical removal of stubborn silicone. Where the self leveling feature is great is where you have a bunch of spider cracks on flat surfaces. Make sure the temp is above 70, poke some foam rope into the cracks with a screwdriver down 1/2", and fill it full of the self leveling adhesive. Often I'll buy cheap painters grade caulk, and use it to plug off an area where I would use foam, and often find it much less expensive and less labor intensive.
     
  7. Empty Skies

    Empty Skies Elite Refuge Member

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    Haven't tried the sikafex & it sounds like a great product. NP-1 with a little sand thrown on to match texture is great also.
     
  8. ncmallard78

    ncmallard78 Senior Refuge Member

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    what are the benefits of calking cracks in a driveway? thanks!
     
  9. 10GAGENUT

    10GAGENUT Elite Refuge Member Flyway Manager

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    Keeps water from getting down in the cracks ,freezing and making bigger cracks. Basically as I learned when I first got in the construction industry there are two kinds of concrete, concrete that is going to crack and concrete that has cracked already.....age, intial pouring and finishing usually determine how fast or slowly it's going to crack on you.
     
  10. h2ofwlr

    h2ofwlr Elite Refuge Member

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    Unless in a northern (frost heaving) climate, very few bebefits really. Up North you need 3 things for forst heaving--cold and water and fine soils (clay). So if you help keep the water out--less heaving in the winter.

    But one area that it really shines is between the slab and the garage/house. At the garage it keeps out the salt from running down along the foundation--as the salt eats away the foundation-so a big plus. At the verticle places on the house where it butts up it helps to shed the water away from the foundation for a drier basement. And away from the garage on the driveway it helps to keep the weeds down from growing up on the control joints between the slabs.

    Also I see a misconception that should be cleared up on the use of foam backer rod. It is used for both vertical and horizontal applications. It really comes into play on vertical areas. Because on a horizontal crack you can use sand as a backer. Meaning fill the open joint to within 1/2" from the top and then caulk it. And also backer rod is used for both self leveling and standard bodied caulking.

    Also, as mentioned sand sprinkled on top of the caulking right away as you are caulking (before it skims over) can indeed make it look more natural. In foot traffic areas I use Silica sand. if mataching on an old slab then the natural sand it better. Also--many guys may not be aware of this--there are a many colors that caulking comes in. So you can often come close in color to the slab or whatever area you are working on--like gap sealing on wood with stain--some use for example redwood color.

    Another thing--so why does concrete crack? Well several things come into play. First is that a good % of the concrete mix is water--and it evaporates. Thus shrinakage cracks can happen (these look like spider webs type of cracks). Movement - this can be from soils setting, expansion/contraction due to heat/cold. This is why architects specifiy that 80 s.f. at mopst per slab between the control joints. The control joints are the grooved joints made when finishing the concrete. Also sometimes a day later they come in and saw the control joints into the slabs. Commercial projects the joints may be plastic strips in the floor. Depth of "cut" is critical, as too often they are not deep enough and thus you get cracks not at the control joint. As the name implies--the purpose of the control joint is to control where the concrete slab cracks.

    Control joints are not to be confused with expansion joints as they are 2 seperate things and serve to do 2 different purposes. The expansion joint is used to keep the concrete from buckling under the pressure of expansion. Once in a while you'll hear about highways heaving up due to the expansion of the concrete due to the heat. We just had that happen yesterday here where 3 of 4 lanes were closed as it heaving upwards dramatically. So the purpose of using expansion joints is so to lessen the chances of buckling upwards or basically so the slabs stay in place.
     

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