13 replies to this topic

[David Zawadzki]

Anyone have CAD Details showing the correct way to do this?

 

The homeowner wants to add a short stemwall paralell and below the existing crawlspace stemwall.  I tried to explain "angle of repose" to him and advised him to talk to an engineer or his foundation contractor but he refuses to believe any of us.  He is in an area with no building dept or inspections.  I told him that he still had to contend with the laws of physics.

 

I attached his change request.  Please note his foundation detail on the right side.

 

I figure if I can show him a standard CAD detail, he might understand what we are saying.

 

Any help would be appreciated.

 

Thank you!

Attached Thumbnails

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[David Zawadzki]

Found a couple videos that might help the customer understand:

https://youtu.be/IpH8IP2I6LU

https://youtu.be/3wsreZ6sjtU

Wish me good luck

[Steve and Carla Farnam]

David I do not know if I would run with this foundation with just good luck. The engineering

on the transition from crawlspace to full basement , as you know, incorporates many loading

factors both vertical and lateral combined with soils etc. I would suggest that if the client wishes

not to use an engineers services that the client supply the detailed drawings and notes necessary

to complete the transitional foundation and that page could then be added to the plan set directing

any liability to the client, similar to a page attached with engineers notes or a roof truss plan.

 I Wish You Good Luck!!

[Gary McKeon]

Even with those disclaimers I wouldn't touch this job. The liability is not worth it and you really can't escape it. Not only do you have all the different structural components with relevant loadings, you also have to consider water intrusion. Much bigger issue than most think. Some jobs just make sense to walk away from so you can sleep easier. My two cents.

[David Zawadzki]

Good points above...

I enjoy the ones who watch hgtv and become an expert overnight.

[Mark Petri]

Some of the best jobs are the ones you don't get!

[Keith Almond]

What steps should you take? ... Big ones and fast!

[Dennis Hilborn]

Good points above...

I enjoy the ones who watch hgtv and become an expert overnight.

And the ones that see it on the show and think there is a button labeled "create the house and do all the drawings automatically", well they have one on TV.

[Harlon Suttle]

This is a common problem, and is called UNDERPINNING, very time consuming and costly....easy enough to do, but only in extreme cases is it used....my suggestion, contact foundation underpinning contractors, and ask for a quote etc....they wiil do the engineering and construction...but your home owner is going to faint after they see the cost ....and probably revise their plans....drop me a private message if I can be of additional help....

[Harlon Suttle]

One additional comment:
The method used is to hand dig piers, usually square about two feet apart and align the inside face with the wall above....thus supporting the existing structure...once concrete in these piers is placed and the concrete has reached the designed strength, then the remaining area between the first piers is removed and the concrete placement is completed....google underpinning...and there are several photos of this method....this is not for a foundation repair, but a method to accomplish what the home owner is requesting....

[Harlon Suttle]

Good old Youtube....here is a good example of what I was explaining above....note the engineered drawings....


https://youtu.be/bXHCBMW9SR0

[David Zawadzki]

I found this...

Some serious photos of underpinning...

http://keasthood.com...ng_101_2016.pdf

[Brian Berzinskis]

I have encountered this before. The engineer's detail showed the underpinning like you are mentioning being done in 3 foot sections and 3 phases so as to not allow the soil and the existing footing collapse.

 

Also in my experience the new basement wall was put under the existing crawl space wall for loading down to the new foundation and footing. Then the old footing was cut off on the interior basement side so it was not just floating up mid wall.

[Mark Petri]

Water penetration at the cold joint will likely be a big concern and ought to be addressed. Which, in my mind, means excavation around the foundation and exposing the existing. By the time you do that, you may be better off cribbing the floor, walls and roof structure and pouring a whole new foundation. Doubt the cost would be that much different by the time all is said and done.