Addition to existing basement waterproofing

[structuralengr89]

I am adding an addition to an existing basement on a commercial building and have a question on waterproofing. I believe the existing building basement walls are on a shallow foundation. The addition basement walls will be on a deep foundation.

I would like to tie the new concrete walls to the existing concrete walls, have adequate waterproofing, but still allow some vertical movement between the existing (shallow foundation) and new (deep foundation). Is there a system that can accomplish this?

Thanks.

 

[structuralengr89]

See the attached file.

I would like to have a connection that is waterproof (Can I have a waterstop at an E.J.?)
I would like to brace the existing wall laterally
I would like to allow for vertical movement due to the different foundation systems.

Thoughts?

 

[JAE]

Possibly use a retrofit waterstop -
See this pdf catalog by Greenstreak (there are others)

http://www.greenstreak.com/subpacks/Waterstop_Catalog_0411.pdf

Look at page 10 and their model 581 water stop.

Might call your more local water stop manufacturer's and see what products they might have available.

 

[hokie66]

Why do you want to bolt the two walls together? I would lean toward just providing the joint, and using flexible sheet waterproofing which will go across the joint.

 

[structuralengr89]

JAE - thanks for the link. I will get in touch with someone with greenstreak. I've used their swellstop product in the past.

Hokie - I am removing a section of the existing wall that was cast monolithically and perpendicular to the wall I am butting against. I do not have plans for the existing structure and am not sure if the section I am removing was originally designed to provide lateral support.

Hokie - Are you suggesting having an EJ and then placing flexible sheet waterproofing at the EJ. What are your thoughts on the product JAE mentioned?

ThankS JAE and Hokie for your help!

 

[Backcheckrage]

Maybe it's just me, but but why allow vertical movement for a foundation system? Can the floor and wall framing above tolerate the differential movement you have allowed for?
Generally speaking, primary founding elements for a building should be tied together.
If you're mixing shallow with piled founds, you might create a hard point in the foundation system potentially causing some damage to the superstructure walls/framing over time due to differential vertical movements. maybe horizontal as well if existg shallow founds are on a slope or nearer to a creek or river or other body?

Maybe underpin the existg founds as well with screwpiles/micropiles to mitigate differential settlement risks?

just my thoughts.

 

[hokie66]

I agree with allowing the two structures to settle independently, but I wouldn't do it with steel angles and slotted holes. I would just cast the new wall directly against the existing, with a bond breaker between, probably just a couple of sheets of polyethylene. No gap or compressible material. You can use a waterstop like the new to old ones shown in the Greenstreak information, but I think stopping the water at the outside face is more important, by using a flexible sheet membrane.

 

[Mepooooo]

Yep, you can trust Greensteak.

http://flolly.com/basement-ideas/