crushed stone footings

[billconner]

I somehow knew that wood and precast concrete foundation walls could sit on crushed stone footings, but suprised when reading the code (NY but basically 2018 IRC) that any foundation type, including those of concrete or fully grouted stem walls could be set on crushed stone footer.

Any experience here with this type of footer that you are willing to share?

 

[Skooterj]

I built my house 4 years ago with a Superior Walls precast basement wall system set on a crushed stone footer. Basement was done in 3 days, including the slab. Walls were up in 4 hours. My only issue is Superior Walls forgot that I was putting 2 inches of foam below the slab and the one door opening I had to a safe room was 2 inches too short without modifying.

 

[duneslider]

I built my house 4 years ago with a Superior Walls precast basement wall system set on a crushed stone footer. Basement was done in 3 days, including the slab. Walls were up in 4 hours. My only issue is Superior Walls forgot that I was putting 2 inches of foam below the slab and the one door opening I had to a safe room was 2 inches too short without modifying.

Just checked them out and that is one of the coolest things I have seen in the building industry in a long time. Looks like an awesome product, would love to see one in person. No dealers in my state at the moment. Just curious but did you compare cost of this to a regular concrete foundation?

I have always wondered how the crushed stone footers handle seismic loads?

 

[billconner]

I like the Superior Walls, and for a house with basement, great qualities, probably for only a little more. For an unheated garage on grade - wow - like $20k.

I'm looking at blocks, fully grouted, not all that different structurally.

 

[Wheelingit]

I built my house in 1997 with Superior Walls on crushed stone. It was a great decision. After the stone was down the walls were done in a day. It is also a very good system for a very dry basement and that was a major concern of mine since every house that I had beforehand had damp basements. So after 24 years and one earthquake I am satisfied and would do it again.

 

[Skooterj]

I had a couple local concrete guys quote me a traditional poured wall basement v. the Superior Walls. The poured walls were slightly cheaper, like $2000 ish. But by the time I added the 2 inches of foam insulation on the walls, plus the need to waterproof the poured walls, the Superior Walls were actually cheaper. Superior Walls are factory poured from 5000 PSI concrete, so you do not need to add any external waterproofing membrane. The framing detail for the floor system on top of the walls is pretty intricate, and my framing contractor hated the extra work, but he bid the job and had the eat the costs because he didn't do his research ahead of time. I did have a slight issue during backfill, one of the walls tipped slightly inward (I think the excavator hit it with his bucket), so we had to dig it back out and brace it before backfilling again. If I had it to do again, I would overbuild the floor system to add extra stability before backfilling. Pushing that wall back out after the floor was attached sucked.

 

[Wheelingit]

In my case I poured the floor before backfilling and all was good.

 

[Skooterj]

I had my basement slab poured before backfilling, and the sub floor all framed per Superior Walls framing detail. One wall still tipped in about 2 inches. Made a huge hump in my sub floor. Had to remove all the backfill on that side, pull the wall back plumb, add extra bracing and replace the backfill material. If I ever do it again, I'll have a solid beam running from the front wall to the back wall. The tipped in wall ran parallel to all my I-Joints. Running a solid beam would have prevented the whole issue by being perpendicular to the problem wall.

 

[billconner]

I am a little surprised that the attachment - bolted? - to the adjacent walls was insufficient.

 

[Skooterj]

Yes, the top plate is bolted to the top of the walls. All my joists run parallel to the basement wall in question. Superior walls details that when using I-Joists ran parallel, bracing made up of short pieces of I-Joist need to be placed between the first 4 floor joists every 4 feet to help support the backfill weight. The tipped in wall is 38 feet long, and only tipped in near the middle of the wall. The ends were still plumb. Unfortunately, the middle of this span is right where my front door is, causing a hump to form in the subfloor. about 4 feet in from the door. Once we relieved the pressure, we added more bracing to pick up an additional 4 joists once we pulled the wall back to plumb. Like I said, I am pretty sure the wall got hit by the excavator, as there was a scuff mark on the exterior concrete. I already had a support wall framed in the basement to help with the floor joist span, but if I had to do it again, I would replace the framed wall with a solid beam, probably steel, to not only reduce the span of my floor joists, but also to make sure the basement walls couldn't move without bending the steel beam. Set my build back about 3 weeks getting the wall plumb.

 

[billconner]

I am surprised the wall "bowed" but glad for you it didn't break. I just assumed they were stiffer from end to end. Very interesting and helpful. Thanks.