Looking for help with details for a walk-out footing/foundation basement wall. Looking at a garden view basement with only a full walk-out at a double entry door.
I have limted access to 2006 IRC, but did not find much help. I am in a 48″ fraost depth area.
Questions:
Is there a minimum turnback for lower wall?
Is ther any limits/requirements of rise/run of stepped footings along footing/foundation wall at walkout door and/or any at side walls?
Draingage details at lowest wall transition and at other steps in foundation?
Thanks in advance,
TG
Replies
All footings need to be Frost Depth + AHJ from nearest soil surface.
Stepdown overlaps requirements are usually a ratio. I have seen 2:3 and 1:1. That is: the upper part must extend that ratio of length:height over the lower part. See your AHJ.
Perimeter Drainage needs to be at or slightly below the basement floor, it doesn't need to be at the footings that are frost depth below the floor. Except at the walkout, all footings, irregardless of steps, are slightly below the floor.
Don't use the Perimeter Drains for Gutter Drains. Put cleanouts every 90' or 360* of elbows, wwhichever is shortest.
Thanks for the feedback. However I am not familar with AHJ?
Currently I am going to return the lowest (garden) wall 2'-8" feet from the corner and then step footing up from there. I have read that a 2 feet minimum is recomended but found it to be a only a "rule of thumb" ???
Tim
Can you explain the overlap in a different way.My house is T shaped.Two story with slab floor and separate frost foundation. But the stem of the T is the garage and it is 1/2 story higher than the house.The garage is also 2 story with shop/basement in the lower level, which is 1/2 story above the house first floor.The back side of the house foundation is concrete up to the level of the garage floor. About 12' above the 1st floor house floor.I have a water problem and dug up where the garage meets the house. While the foundation was all contigous from the garage into and around the house. But the footing for the garage stopped short of the house.
I guess that it had to otherwise there would be no way to form up the house foundation walls. Just surprised me.Just to make sure that it is clear. The garage foundation side wall hits the house/garage front wall foundation perpendicular.
Bill,
Can you explain the overlap in a different way
A:B = 2:3 or 1:1
View Image
the footing for the garage stopped short of the house
View Image
No Slabs shown, just footings and foundations.
FYI, I use "Foundation" to mean walls sitting on footings.SamT
Gotcha.I have that step down on the two sides of the house. Don't remember what the footings where like and of course they can be seen now.And yes, that 2nd drawing is exactly like what I have where the garage meets the house.
"And yes, that 2nd drawing is exactly like what I have where the garage meets the house"
That's a 'Weak Link,' Like a fuse. Supposed to be there. Much, much cheaper than what's needed to PROPERLY connect them.
When the house and garage settle seperately, the interconnecting slab will crack in two places and ramp, rather than one massive crack that tries to shear the rebar off. Or takes the basement with it.
SamT
Here is a pic of the end of a house-on-foundation, and lines are drawn to show how final grading will be brought to the walls. Essentially, we have a small-scoop walkout.
As you can see, the foundation with 8' deep walls everywhere, has a stepdown frostwall under it where the walkout exposure is happening.
The term "AHJ" is shortspeak here for "authority having jurisdiction," meaning, local building inspector.
View Image
Gene,
How did you handle the grade from the door on out. I am assuming the finish grade had to slope away from the door, but curious as to how far it had to go as the slopes on either side look pretty steap. This looks similar to the situation I may have on a house I am building for myself.
Jim
This job was supposed to start this fall but is postponed until spring, so we cannot show you any pics of real sitework yet.
The footprint of the house sits on a reasonably level pad, but a 10 degree downslope begins right at the rear wall line. We will have no trouble getting a nice little fallaway from that rear door, and the cut from the foundation hole will be used to embank things on both sides.
Thanks Gene,
That helps. My lot is also fairly flat excapt towards the rear, I had been wondering if a walkout was possible. Your picture makes me think it will be.
Thanks Again
Jim