can I pour concrete against a framed exterior wall?
 

We want to add a patio by our back dooe but one of the homes exterior walls is 18" lower than the adjacent wall (due to a sunken room in the house). A concrete contractor told us he can remove some siding, apply a concrete board and rubber membrane and pour concrete against it. Is this a good practice? We live in Minnesota with freeze/thaw conditions so the slab can move.

Any help/ideas would be greatly appreciated.

Thank you,
Jeri B

Welcome Jeri B:
Yes, that sounds like a good plan. The only thing I would want to add is butyl rubber caulking in the crack between the house and concrete to keep water out of there and remain flexible during temperature movements.
Glenn

I would not do it and you will probably find a lot of good contractors that would not touch it with a 10' pole. Cement board and a "waterproof" sealer and membrane, especially when it comes to the frost movement you can get in your area.

You apparently are not under a code, but if you ever go to sell, any reasonably imtellegent home inspector should spot that. Just because a code is not contolling now, that has nothing doing when you go to sell.

How does a wood frame wall enter into a patio installation? Is the patio above aliving area?

I too would be reluctant. Is there any way to change grade and just do steps? If you DID do it I would also make sure you had a slope away from the house. No, I wouldn't do it.