Problem with modified bond beam conversion

[Bill O]

Hi,
I'm currently having my modified pool bond beam converted to a "normal" bond beam. I've discovered that there is a cold joint between the high strength concrete that they used for the build up and the original pool shell. The way I can tell is because when I hydrate the new concrete, water ponds behind it and leaks under it into the pool. Hopefully, the photos will help to explain what is happening. Thank you so much to anyone who can help. I am way in over my head on this.

 

[ajw22]

You cannot help but have a cold joint when you put new concrete on top of old. It looks like you have rebar epoxied to the old concrete to structurally join the two concrete layers. Concrete is not waterproof. The plaster will waterproof the concrete.

I don't know what your pool finish plans are. It looks like your tile line may go along the joint between the concrete. Are there plans to put a waterproofing layer like Basecrete along the concrete joint?

Welcome To Basecrete - #1 Concrete Waterproofing Product

www.basecreteusa.com

 

[Bill O]

You cannot help but have a cold joint when you put new concrete on top of old. It looks like you have rebar epoxied to the old concrete to structurally join the two concrete layers. Concrete is not waterproof. The plaster will waterproof the concrete.

I don't know what your pool finish plans are. It looks like your tile line may go along the joint between the concrete. Are there plans to put a waterproofing layer like Basecrete along the concrete joint?

Welcome To Basecrete - #1 Concrete Waterproofing Product

www.basecreteusa.com

Thank you for your replay, Allen!
They are going to use Laticrete waterproofing under the tile. The tile will be a few inches above the cold joint. The new pour is mostly "water resistant", unfortunately there are a few areas where water behind the new pour literally streams out. I think this is because they didn't consolidate the new concrete at all. (bang the forms with a mallet, stab with some rebar, or even key in the first inch of concrete). I did apply bonding agent on my own dime, but it didnt make a difference in the areas where the concrete didn't make it to the bottom of the forms.

 

[ajw22]

I don't think the concrete crew gave any thought to waterproofing the joint. Structurally it was done with the rebar.

Have you considered putting some hydraulic cement into the joint in the areas it is passing water through?

 

[Bill O]

I don't think the concrete crew gave any thought to waterproofing the joint. Structurally it was done with the rebar.

Have you considered putting some hydraulic cement into the joint in the areas it is passing water through?

Great call, Allen! I'm about to do that right now. I filled up behind the beam with wtaer. I am going to undercut holes where the water is coming through with my grinder. Chisel it out. Drain the beam. Pack cut holes with hydraulic cement. The beam is about 95% dry across the face, but there is water trickling out of a hole about every 5 feet. The repair company keeps telling me that concrete isnt waterproof, but in this case it actually appears to be extremely water resistant except in the spots where they left a void from front to back between the new and the old.
One of my big concerns is excessive water penetration rotting out the rebar. There is plenty of it in the new beam that is NOT encased in concrete to eventually rust, expand and spall the plaster.

 

[Bill O]

I don't think the concrete crew gave any thought to waterproofing the joint. Structurally it was done with the rebar.

Have you considered putting some hydraulic cement into the joint in the areas it is passing water through?

i made a short video here https://youtu.be/Q9yAC8oEv_g

 

[lasvegaspools]

Would advise waterproofing both sides of the beam repair and use mesh at the cold joint. Basecrete would work well or and other waterproofer that is flexible incase of future movement.

 

[Bill O]

Would advise waterproofing both sides of the beam repair and use mesh at the cold joint. Basecrete would work well or and other waterproofer that is flexible incase of future movement.

They said they are going to fill the trough behind the beam with concrete, to make it one solid mass. This will eliminate the trough for collecting water, but will also introduce 2 more cold joints.
Would I still need to waterproof behind the beam if they pour concrete?
Would I be able to use a cheaper waterproofing, such as bitumen, since it will be covered in concrete?
I will request that they waterproof the front side with Basecrete and use mesh on the joint. That makes sense.
Thank you for taking the time to respond. I appreciate you.

 

[Bill O]

Would advise waterproofing both sides of the beam repair and use mesh at the cold joint. Basecrete would work well or and other waterproofer that is flexible incase of future movement.

Hi
this is a little off topic but Im guessing that you build pools in Las Vegas so you might know. All the poured concrete cantilevered deck guys i have spoken with say that they dont put any reinforcement in their decks. I thought i needed steel to create a bonding grid under the pool deck as per NEC. is that not code in Las Vegas?
thank you again for all of your great advice!

 

[lasvegaspools]

Typically no wire or rear in pool decks in Vegas, only if engineer calls for it due to soil conditions.

 

[Bill O]

Typically no wire or rear in pool decks in Vegas, only if engineer calls for it due to soil conditions.

Thank you!