Garage Doors - Concrete Gaps - Repair Options?

[giradman]

Hello All - this is our 40th year in this house - we've replaced the garage doors recently - gaps of variable widths have developed over these years between the garage foundation and the concrete slabs, as shown in the pics attached.  I would like to fill these in when spring comes and the weather if warmer.  I would clean out the loose cement and debris first and fill-in any deep gaps w/ sand - should I just mix up some cement and troll into the gaps or use a different product - would a silicone caulk or similar material in the minimal gap areas be advised - thanks for any comments.  Dave

[Cooler]

I have a similar problem, though I suspect mine is worse.  I have those short concrete slabs and a blacktop driveway.  The slabs don't have a sufficient footing and they heave.  I now have two slabs, where before I had one.  It split right in the middle.  

One extremely cold winter had my garage doors closing and then re-opening.  The slab had heaved and the garage door safety sensor was indicating an obstruction.  I had to adjust the closing to accommodate and again in the warm weather because then I had a gap.

If the gap is a heaving issue then only tar or some rubber-like product will work.

I would try something like this:  http://www.dsbrown.com/Pavements/Delpatch.aspx

Note that the larger gaps are usually filled first with special foam tubing and then the patch is applied.

[EdL]

The small gaps I would use the Sikaflex & backer rod......the large one, I've got nothing.

Probably should've mentioned it in the other thread, the Sikaflex is not a caulk. It's a very thick self-leveling liquid so it will flow into the gap easily. I try to leave the tube in the sun for a while to make it dispense easier. Check the date on the tube if you use it, there is a shelf life and they're not kidding.

Ed

[Mr_Mike]

Yet again. Sikaflex and backer rod. Works everytime. There should never have been a hard boundary there anyway.

RE: Ed's comment on sikaflex flowing. It will absolutely flow and drain out if not properly dammed. If I can't really dam up the location, I'll squirt in some sikaflex to fill in the bottom and come back the next day and fill for effect.

[giradman]

Yet again.  Sikaflex and backer rod.  Works everytime.  There should never have been a hard boundary there anyway.  

RE:  Ed's comment on sikaflex flowing.  It will absolutely flow and drain out if not properly dammed.  If I can't really dam up the location, I'll squirt in some sikaflex to fill in the bottom and come back the next day and fill for effect.

Thanks all for your comments - I'll take a look @ the product Sikaflex - Amazon seems to have a LOT of options, so not sure which one to pick - assume that the recommendation is for filling the smaller cracks?  So, still need a solution for the places the 'cement' has broken?

@ Mike - put in bold your comment above - what should have been done?  This house was about 6-7 years old when we bought it so early 1970s construction - what was the practice back then for this type of interface?  Should I get a professional opinion to remove the entire length of the cement and replace w/ a 'modern' alternative?  Sounds costly but may be a better option - just spent $2K on some professional landscape lighting, so willing to obtain some estimates.  Thanks again.  Dave

[Mr_Mike]

Any place you can have relative movement, especially changes in direction, one should allow that movement. I suppose back then they should have used an asphalt based expansion joint.

But, it has lasted 40 years. I assume if you packed the joint with cement or grout it would last that long again.

My personal opinion would be to caulk the thin joint and use backer rod and sikaflex on the thick areas. Longer term, perhaps chip out and do the whole joint when it warms up.

[giradman]

Any place you can have relative movement,  especially changes in direction,  one should allow that movement. I suppose back then they should have used an asphalt based expansion joint.

But,  it has lasted 40 years. I assume if you packed the joint with cement or grout it would last that long again.

My personal opinion would be to caulk the thin joint and use backer rod and sikaflex on the thick areas. Longer term,  perhaps chip out and do the whole joint when it warms up.

Thanks Mike - sounds like a job that I can do myself - will wait a few months for warmer weather - Dave

[geek2me]

what should have been done?  This house was about 6-7 years old when we bought it so early 1970s construction - what was the practice back then for this type of interface?

What you have is normal and fine, still done that way today.  No real need for an asphalt filler strip, the concrete doesn't really bond to the foundation and shrinks a bit as it cures, creating the natural small gap shown in your photos. 

The bigger concern is the broken parts - which suggests the preparation was insufficient.  Take a carpenter's hammer and tap around the broken areas.  You are listening for a hollow sound.  Use this technique to map out the void.

If the void is very large, you should have it fixed.  Look up "slab jacking" to find companies that will inject a flowable concrete to fill the void and stabilize the pad.

If the void is small, just caulking the broken part will work.  Not a bad idea to caulk the gap as well, to control water infiltration.

[giradman]

What you have is normal and fine, still done that way today.  No real need for an asphalt filler strip, the concrete doesn't really bond to the foundation and shrinks a bit as it cures, creating the natural small gap shown in your photos. 

The bigger concern is the broken parts - which suggests the preparation was insufficient.  Take a carpenter's hammer and tap around the broken areas.  You are listening for a hollow sound.  Use this technique to map out the void.

If the void is very large, you should have it fixed.  Look up "slab jacking" to find companies that will inject a flowable concrete to fill the void and stabilize the pad.

If the void is small, just caulking the broken part will work.  Not a bad idea to caulk the gap as well, to control water infiltration.

Thanks for the reassurance and comments - will certainly check out the area w/ the larger broken pieces to determine the depth and size of the wider gaps - Dave

[Lynden]

In addition to reducing the amount of sealant needed, the other reasons for using backer rod in a joint or crack are to prevent three-point contact of the sealant, to control the thickness of the sealant and to give the sealant the desired hourglass shape. 

Backer Rod:

If the joint or crack to be sealed is 1/4" wide or wider, it is best to install foam backer rod in the joint - to the proper depth - before applying the caulk.
The reasons are:

1) It saves money. Backer rod is generally cheaper than a good quality caulking compound, and most of the joint can be filled with the backer rod before the actual sealant is installed.
2) It provides the means to form an "hourglass" cross-sectional shape to the bead of sealant. This geometric shape allows the sealant to handle the inevitable joint movement much more easily than any other configuration. (The reason: Large surface areas of adhesion are established at the sides of the joint, while a relatively thin cross-section of sealant is left in the center of the joint to allow for easy flexing)
3) It provides a "bond-breaking" surface at the bottom/rear of the joint or crack that prevents the sealant from establishing three-point adhesion which, if allowed to occur, can lead to early failure.
5) It allows for additional pressure to be applied to the sealant during the "tooling" process, which further favors more sealant being forced into intimate contact with the sides of the joint for better adhesion.

http://www.chamberlinltd.com/media/files...detail.jpg