Building My Dream

[Gary Fowler]

It would be essential to backfill with the clay. If you dig a hole in clay soils and backfill with crushed stone, you will create a "bathtub" that will not drain at all as the clay will hold the water that percolates thru the stone. Unless you provide a drain at the bottom of the excavation so the accumulated water will drain off, it will be holding this water for a long time as the clay doesnt absorb water much at all. You should plan to level the sub-base so that it will drain away all the water then install 3-6" of crushed stone on top. This will be cheaper also than buying material to fill in an excavation. You do need to compact the clay with a good compaction tool like a vibratory roller or hand operated "jumping jack". Vibratory plate compactors dont do a very good job with clay material unless you run them on about 2-3" lifts

 

[kevin37b]

Yes , by all means use the clay to regrade .

 

[SPIKER]

I would also look at installing drain tile around the 3 high sides out to the low side graded to flow water away from the high side. this trench should be deeper than all the footings so it collects water coming in under the top surface as well as gravel up to daylight to catch and move flowing water in heavy rains away from the pole barn.

I had similar issues with my barn it is built on a slope that had a little over 30" of fall from corner to corner on a 50x50 pad.

this shows some grading AFTER the barn was up it does not look very un-level here or like there are 3 swells in the photo but there are. all the raw clay/dirt/topsoil makes it look almost level and this photo has about 4 overall feet of fall shown in it. level is deceiving lol...


in this pic early the right far corner is the high side/corner


this is the low side, corner.


this shows some of the hill side fall more directly the skirt boards are 8"



On mine I dug around the outside and installed 4" perf tile with the sleeve over it. I tamped hard clay at an angle back/down away from the barn into the tile. I then stapled 6 mil black plastic to the barn and sloped it down into the bottom of this trench, put in the tile and laid a 2nd layer of plastic out and onto the top/middle of the tile. then back filled with gravel in the trench and onto the plastic. there is a layer of landscape fabric water goes thru it and then some top soil on top.

I made the swells around the outside using the topsoil and clay. and added tile to the TOP side of the swells with a layer of gravel to pull water that flows downhill towards the barn out & into large deep drywells I made.
There were about 500 old hollow core 12" blocks that I used underground to make the drywells.


Mark

 

[SteveSmith]

Thanks everyone for your feedback. We used 12" of crusher run for the drive as that us what the excavator recommended. The previous version of the driveway had a few inches of gravel on it that just disappeared when we drove on it before freeze up and got worse this spring. I would rather overbuild than be sorry later. (A neighbour used less gravel on his new drive and buried his 4x4). Our truck and RV combo is at least 25000 lb. and we will go in and out with it in all seasons.
I am not worried about the excavation for the barn ending up like a bathtub as there are two sides that will be built up rather than excavated. What I understand is the excavation really only needs to be as large as the barn as long as the clay is graded such that the water runs away from the building into a swale? I also see building berms to direct the runoff that comes down the hill so it is well away from the building.
Is 6" of crusher run, topped by a few inches of 3/4 stone enough to go under the slab?
Yes we will use a single drum vibratory roller to pack everything. Driving one seems rather straight forward!
Steve

 

[broadway3000]

Looks great. Work never ends. Hope you love it.

 

[SteveSmith]

Welcome to TBN Steve.

Cool, another house building thread for me to follow!

Have you had a soils and percolation test done on the area where the house and leach field will be? If not, spend the bucks and get it done as it will determine the type of foundation and prep work that needs to be done. I'm sure Ontario will require those tests anyway. In my area, our clay soils tend to be expansive (e.g. hot), and I'd be real leery of using clay as a backfill material without an engineer's approval and instructions.

Yes we will need a soil test for the septic (local regs) but I don't understand why get it done for the house site. We would backfill with sand. Is there something else to consider?
Steve

 

[dave1949]

Yes we will need a soil test for the septic (local regs) but I don't understand why get it done for the house site. We would backfill with sand. Is there something else to consider?
Steve

Most people here, including me, have no idea what your soil conditions are. Different soils and drainage situations need different building techniques.

It is very worthwhile to get a complete understanding of your soil and foundation construction needs now before you make a costly mistake, or a headache you will live with forever. A soils test interpreted by an engineer who gives some general recommendations is not a bad thing to have. Foundation do-overs are just about impossible.

 

[stuckmotor]

Steve,
Thanks for explaining about why you used so much crusher run. I guess your soil conditions require more gravel than ours.

 

[mjncad]

Yes we will need a soil test for the septic (local regs) but I don't understand why get it done for the house site. We would backfill with sand. Is there something else to consider?
Steve

Dave says it quite well below as for getting a soils test for your foundation. You don't want to be nickel wise and dollar foolish when it comes to your foundation.

In the Denver area most houses are built on piers/caissons due to our expansive clay soils (Bentonite); but when I had a soils and perc test done for a house to be built on the plains 40-miles east of Denver, the report said I could use spread footings instead of piers.

I paid $1,200 for a soils test for a 2,500 square foot house with 1,200 square foot attached garage, a 2,400 square foot outbuilding and two leech fields. Although this house will now never be built, I consider the amount spent for a P.E. stamped and signed report a bargain.

Most people here, including me, have no idea what your soil conditions are. Different soils and drainage situations need different building techniques.

It is very worthwhile to get a complete understanding of your soil and foundation construction needs now before you make a costly mistake, or a headache you will live with forever. A soils test interpreted by an engineer who gives some general recommendations is not a bad thing to have. Foundation do-overs are just about impossible.

Thanks Dave, you said it best.

 

[SteveSmith]

Thanks
I had not considered a soil test for the house but I will now.
Steve