Vertical Concrete Repair
Vertical Concrete Repair
(OP)
I need to present method and materials to repair on the vertical surface of a chipped corner at the top of an exterior concrete foundation wall.
Previously, the exterior brick veneer had a 1" overhang outside of the face of the foundation wall, but due to mechanical damage, the foundation corner was chipped such that the brick now overhangs 2" to 2 1/2". The damage tapers down to normal about 8" down vertically from the top of the wall and about 12" horizontally from the corner of the foundation.
The brick and backup blockwork at the corner is damaged and will be removed and rebuilt as part of the process.
The issue that troublems me about just trowelling on a thin patch is that the patch needs to bear weight along the vertical shear surface, and the patch is so thin there is no way to get reinforcing/dowels into the detail.
We might also need to deal with marginally cold weather as the repair may take place in late March in New England.
We can impliment any amount of concrete removal to make this a more dependable repair, so I am tempted to just chop the entire top of the wall down some significant amount and pour a cap, but lesser approach advise would be welcomed.
Previously, the exterior brick veneer had a 1" overhang outside of the face of the foundation wall, but due to mechanical damage, the foundation corner was chipped such that the brick now overhangs 2" to 2 1/2". The damage tapers down to normal about 8" down vertically from the top of the wall and about 12" horizontally from the corner of the foundation.
The brick and backup blockwork at the corner is damaged and will be removed and rebuilt as part of the process.
The issue that troublems me about just trowelling on a thin patch is that the patch needs to bear weight along the vertical shear surface, and the patch is so thin there is no way to get reinforcing/dowels into the detail.
We might also need to deal with marginally cold weather as the repair may take place in late March in New England.
We can impliment any amount of concrete removal to make this a more dependable repair, so I am tempted to just chop the entire top of the wall down some significant amount and pour a cap, but lesser approach advise would be welcomed.






RE: Vertical Concrete Repair
RE: Vertical Concrete Repair
Prefereably, though, I would recommend chipping back the concrete to a minimum thickness, perhaps 1" to 1 1/2", and then patching. Even better, a lot of patch details require removal of concrete back to expose the reinforcing steel. This would be taken back to allow about a 3/4" gap between the bar and the back side of the patch such that the new material would completely surround the exposed rebar. You can also add small 9 gage stainless steel pins, epoxied into the base concrete to further tie the patch to the wall. These pins can be easily fabricated into little "L" shapes where you end up with a small hook in the patch. Plain or epoxy coated WWF can also be laid out in the patch to further help hold it together.
All these are options as to how far you want to go with the "beefing up" of the patch.
RE: Vertical Concrete Repair
This is merely a frost wall, so I don't anticipate significant reinforcing steel; maybe a couple horizontal bars top and bottom of the wall, so they are not going to be of much help.
I didn't expect to feather the repair and expected to increase the missing condition.
As far as "pinning", being such a thin slice, even is cut back to 2" thick, that doesn't leave much concrete cover for corrosion protection. I am sure they spread salt on the immediately adjacent driveway. And I we couldn't count on them not salting at the building anymore than we could expect the truck to not smash through the corner of the building in the first place.
The fact that the brick overhangs the foundation means there will be significant bearing/prying on the piecr that we place there.
Thanks for your imput.
RE: Vertical Concrete Repair
If your repair is on an outside wall and only partial depth, the cured patch material should have a coeff of thermal exp similar to the substrate, and should not form a vapor barrier. Bond strengths also vary, everybody reports them differently. Read the mfgrs data carefully. Good luck.
RE: Vertical Concrete Repair
RE: Vertical Concrete Repair
RE: Vertical Concrete Repair
Patch will be in the weather for its lifespan.
What are some material names to consider?
RE: Vertical Concrete Repair
Agree that Sika materials are good for this application. Not only consider the Sika specific products but look at SikaDur Hi-Mod Epoxy with dry aggregate thrown in. Works well for small, vertical repairs. Consider a layer of carbon fiber overlay after all done to provide some surface protection and overlay.
RE: Vertical Concrete Repair
RE: Vertical Concrete Repair
Some reps suggest an epoxy bonding adhesive followed by a polymer modified cementitious mortar.
Think the epoxy bonding agent is not good?
I would sure like to make a one layer repair, but the material thickness might be up to 2 1/2" at one end and the trowel materials recommend to build it up, and as I see it, that makes for more joints to fail. We can form and pour, but that clouds which material is appropriate.
RE: Vertical Concrete Repair
Polymer modified cementitious products are fine as long as the modulus approximately matches concrete.
You are right, placing 2 1/2" vertically is a challenge in one layer, but done correctly placing multiple layers is fine.
RE: Vertical Concrete Repair
If so, is there bonding agent between each?
RE: Vertical Concrete Repair
Many people also use the scrub coat of the material to bond the repair material to the base concrete instead of epoxy. It that case the base concrete must be SSD (saturated, surface dry).
RE: Vertical Concrete Repair
The company that bought MasterBuilders wouldn't give me the time of day.
Thanks all.