rubble trench foundation

[billconner]

Anyone here ever built a frame building on a rubble trench foundation? I have no seismic or wind issues. Seems simpler - and less expensive - than 4' deep footing and stem wall.

fwiw seems like a separate forum here for foundations, slabs, retaining walls, etc. would make sense.

 

[jack stand]

I actually just did my version of this. A local concrete plant was overstocked with the 2x2x6' interlocking blocks last winter/spring and I bought a trailer load of 20 for $1250 delivered. I excavated down close to frost depth, put in about 18" of 2" stone and set the blocks on top at near finished grade. Then formed up a "cap" 12" thick and poured it.
I have the equipment to do so and it's a stretch from a rubble fountain BUT it made it through last winter's frost cycle without any problems.



It was a pretty cheap foundation and without my requirement of the 12" depth to wet set my post brackets, a simple 4" cap would work for normal stick framing.
This is a building (mostly) for my sawmill.

 

[billconner]

It was looking at a basic 16" wide 48+" deep trench, lined with geotextile and a corrugated drain pipe near bottom. Build a basic 12x8 "footer" on top of that, getting frame 8" or more above grade. I'd like to just put 8" block on rubble trench but not sure that's allowed without engineer. Seemed easier than a alternative. No allowance for insulation or heating - this is a "barn".

 

[jack stand]

How big Bill?
I believe that you and I are both not fans of buring wood (as in a pole bldg). Pre cast concrete piers and a
"platform"?
The block on the rubble sounds like a stretch. I guess that you don't have truck access?

 

[billconner]

I'm a fan of seeing how inexpensively I can do this and still be beautiful. No problem with burying poles - just have to have correct treatment -and much stronger than any bracket. I found post frame was looking like twice or more where I heading now.

28 x 32, 10' clear to attic joists, just standing space under ridge in attic, board and batt walls, asphalt shingle roof. Grade is about 3' above floor in right rear corner, so blocks - 2 courses everywhere, up to 6 at that corner. Looking at a paver floor over slab.

 

[Lynden]

You've probably already done some research. If not, here are a couple of links.

compacted rubble footings

rammed aggregate piers vs stone columns

 

[billconner]

It does make a planning difference when solo diy without heavy equipment. Everything has to be liftable by one person. I have offer of a neighbors loader that helps, especially with "rubble". And I'll have to hire an excavator.

Just got to thinking filling a narrow trench with stone seems a lot easier than building a block wall in a wider trench.

 

[mike93lx]

Just be careful with those trenches. Collapses are deadly and often don't give warning. Narrow ones are especially risky as there is little room for the wall to sluff to

 

[billconner]

Another reason to like the rubble fill. This is very sandy soil - like 88%. (I was trying to figure out if I could use it in concrete - which I read needs 94% sand.)

 

[billconner]

Thinking more I will have to be in trench some. 2' wide if I rent or buy a plate compactor, 16-18" if I hand tamp. 4'-4" deep.

 

[mike93lx]

Thinking more I will have to be in trench some. 2' wide if I rent or buy a plate compactor, 16-18" if I hand tamp. 4'-4" deep.

I have a buddy that does excavation work on the side and was helping me with some drainage at my last house.

He dug a trench comparable to what you describe and I jumped in to do some shovel work. The look on his face told me enough and when I got out, he described what he had been shown in trench safety training. Sure, they talk about worst case in training, but that's enough for me.

I don't climb into trenches that deep anymore. I'd leave it to the pros or find another option. Dirt is heavy

 

[dutchgray]

In sandy soil you would want to dig the sides at 45° or so if you want to work in the bottom, or use trench boxes.

I have been in an 18" wide down to my neck height setting drainage pipes, in clay, which is pretty dangerous, really was do it in a dry summer period, dig a section, get the pipes in and backfill it same day or next, but reality is it would be fine 99 times out of 100 but its the 1 that kills you. Wouldn't do it now.

 

[billconner]

Well, only work in trench is compacting and laying coorugated drainpipe. I can possibly compact from above, manually, but getting pitched drain pipe seems harder. More thinking........

 

[Prospecter]

My outbuildings are both just floating slabs on well drained gravel base. One is well reinforced with rebar and wire. No cracking at all, despite no heat or insulation. The other is my shop. It has only the fiber reinforcing which is "Just as good" (NOT!). My shop is part time heated and well insulated. Not warm, but never below freezing. The slab has cracks, but they have not opened up or separated over 22 years.

 

[billconner]

Unfortunately I have to frost protect this by code, and anything is cheaper than that is what I found.

 

[billconner]

Well, building department approved my permit with the rubble trench. Now to get the big long lead things ordered.

 

[mike93lx]

Good luck with the build. I'll definitely be looking towards following along

 

[billconner]

Excavator shows up tomorrow!

 

[jack stand]

Your going to show us pictures right.

 

[billconner]

plan to...

 

[LS1-IROC]

I have a buddy that does excavation work on the side and was helping me with some drainage at my last house.

He dug a trench comparable to what you describe and I jumped in to do some shovel work. The look on his face told me enough and when I got out, he described what he had been shown in trench safety training. Sure, they talk about worst case in training, but that's enough for me.

I don't climb into trenches that deep anymore. I'd leave it to the pros or find another option. Dirt is heavy

In sandy soil you would want to dig the sides at 45° or so if you want to work in the bottom, or use trench boxes.

I have been in an 18" wide down to my neck height setting drainage pipes, in clay, which is pretty dangerous, really was do it in a dry summer period, dig a section, get the pipes in and backfill it same day or next, but reality is it would be fine 99 times out of 100 but its the 1 that kills you. Wouldn't do it now.

Can't emphasize that enough. 2 gentlemen just lost their lives' in my small town from a collapsed trench. They were working in a trench for a building foundation. Took 1st responders several hours to get them back out.

 

[billconner]

Didn't call 811 so will stay far away from road.

 

[mike93lx]

Didn't call 811 so will stay far away from road.

Why not? It's free, and protects you if something gets hit

 

[billconner]

I meant I didn't call them till this morning. Poco has been here already. I didn't call sooner because I expected excavator next week at earliest. He called last night and asked if today was ok, and I said yes. Since I'm certain the only utilities are near the road, with in 10' easement in my deed, well just do foundation which is not within 50', and run drain to free air near road after the 2 day wait period.

Yes it's free and I should have called last week, just taken by surprise and short notice.

 

[mike93lx]

I meant I didn't call them till this morning. Poco has been here already. I didn't call sooner because I expected excavator next week at earliest. He called last night and asked if today was ok, and I said yes. Since I'm certain the only utilities are near the road, with in 10' easement in my deed, well just do foundation which is not within 50', and run drain to free air near road after the 2 day wait period.

Yes it's free and I should have called last week, just taken by surprise and short notice.

Hey, I call every other week, just in case...never know when you are going to plant a flower

 

[jack stand]

I guess that. Mike's the excavator man.

 

[billconner]

I posted pics in my build thread -
'2 car + detached build' https://www.garagejournal.com/forum/threads/2-car-detached-build.484830/post-9634953

 

[billconner]

Thought interesting that no excavation near road till alle utilities with underground had marked their lines. Spectrum (surprise) was 12' further onto my property - away from road - than marked and than the others. It was also only about 12" deep, much closer to ground than all the others. Bobcat e60 made fast work of coax.

So now one end comes out of ground and spliced to cable on surface to next pedestal. Sure glad the power company does better!