Walkout Basement

[jinman]

</font><font color="blue" class="small">( Am I in over my head?
I have started to dig a 48X32 basement on the side of my hill.
Has anyone dug their own basement.
Red Clay is under the first four feet of sugar sand. )</font>

Don, I'm looking at the way you started your excavation, and I want to make a suggestion. I watched closely as the walkout basement foundation was excavated for my house and they went about it quite differently than you are. I'm attaching an illustration to help me describe how it was done.
My excavation was done completely with a Case 580 LBH. The entire job only took about 6 total hours from the beginning to the final finished grade.

My illustration shows a cross-section looking into the hillside from the side of the excavation site. The first step is to determine the depth of excavation needed at the deepest point.To do this, strart at the point which will be deepest into the hill and stretch a level line out until you are over a point corresponding to the final elevation. Measure the distance from the ground to your level line and you have the depth you must cut to bring the deepest point on the hillside down to final elevation.

Use your backhoe going across the hillside to dig a trench that is exactly the depth you measured in the preceding step. Put your spoil dirt on the uphill side so it doesn't get in the way of subsequent measurements. When you finish the first trench, begin a second trench a little further down the hill. It will be shallower, but it's final elevation will be the same as the previous trench. For example, the third trench in my illustration still needs dirt removed.

Dig as many of these trenches as practical and then begin your excavation into the hill. You will find digging/excavating and maintaining the proper final grade much easier. Stop often to check your elevation with a level line or a laser level if you have one available.

I was a little surprised when I watched the crew begin on my excavation, but it soon became apparent they knew what they were doing by using the trenching method.

 

[txdon]

Eddie, I am not yet retired I still have till the fall to work. I'm getting motivated with your's and Harvey's natural building abilities and wanted to get started. At the end of the summer we should have a good Idea where the 1200' wide tollway will be and decide then to stay or leave. I am trying to think positive and am doing site preparations. I needed some sand for the nearby workshop so I figured might as well start on the basement. The basement will have the downhill side open for the south breeze and view.

Highbeam, After sealing the basement walls, I will install a double french drain around the foundation.

2nstonge, it looks like your walkout basement was a collapsed tunnel before you started your repairs. My walkout basement will have an entire wall at grade. Looks like you made good progress. I know your new below grade walkway will be holding up better.

Jim Wilson, I did run across one rock the size of a loaf of bread but so far that is it. About 100 yards on either side are car sized rocks so I'm keeping my fingers crossed that my rocks will stay small.

Jim, Thanks so much for that good idea on digging cross trenches. I was thinking I messed up then I realized I need to go down about 11' with my 9' backhoe so I will take out the top 4' feet and then start leveling and trenching.

Attached is the side view of the house.

 

[Cityboyfarmer]

Hi Don,

I built my house on a 2200 FT2 basment with 9' walls. I was the general contractor for the project and did as much of the work as I could, but I subbed the basement out. I was there for the entire excavation and pouring of the footings and walls. It was fascinating to say the least.

You are going to need some help to make sure you maintain the elevation per your plans. You will need a transit and someone experienced using it. Your basement is an area where you want to avoid mistakes.

After the crew excavated the basement, they then laid out and dug the footers. #5 rebar on 12" centers was laid in the footings and the concrete poured. I grounded my electrical system in my footing with 100' of 1/0 bare copper wire. This is the absolute best grounding method to use and the time to do it when the rebar is completed.

Here is a photo. I hope these turn out OK as I scanned them from the original in my photo album.

 

[Cityboyfarmer]

Here are the guys laying out the footings.

 

[Cityboyfarmer]

Here is a close-up of the rebar in the footings. You might be able to see the copper ground rod and wire.

 

[Cityboyfarmer]

Jumping ahead to the walls before waterproofing and back-filling. I hope these were helpful. I have quite a few more but don't want to bore you to tears.

I have shots of all the concrete being poured, forms being set, waterproofing being applied etc. if you are interested.

There are about 125 yards of concrete in my home.

 

[Cliff_Johns]

Jinman,
That's just the technique used for sloping joints in Timber framing. You saw down sideways at several places to set depth, then just chisel out between the cuts. Interesting how ideas like that cross all boundries.

Cliff

 

[txdon]

<font color="blue"> "I have shots of all the concrete being poured, forms being set, waterproofing being applied etc. if you are interested." </font>

Cityboyfarmer, Thanks for the photos I am studying each picture with intense interest. Please fill this thread up with the step by step rebarb, form, and pouring pictures. From each picture I am either confirming something I know or learning something I need to know. Thanks so much, TXDon /forums/images/graemlins/smile.gif

 

[jinman]

Cityboyfarmer, that is one BIG basement. Wow! You have more sq. ft. in your basement than my whole house. /forums/images/graemlins/cool.gif

You are right about stopping often to check the elevation with a transit. I think on a smaller excavation and using a laser transit, you can turn the two-man job into a one-man job if you get on and off the tractor a lot. But it sure makes it easier when you have one person checking and another one digging. /forums/images/graemlins/smile.gif

 

[dooleysm]

Very interesting thread to me. My wife and I, along with lots of help from both our families, built our own home last year. My cousin did the walkout basement excavation with his trackhoe. He never got off the machine or took any measurements until he had the whole thing pretty well done. At that point my father-in-law and brother-in-law measure it with a laser level and found he was within 6 inches all the way around. Some work with a bobcat the next day to level the floor and walls out and we were set. It took him about 10 hours on the trackhoe (including topsoil removal for the garage and 300' of driveway) and another 3 hours or so on the bobcat. Our basement was about 52'x32'.

I learned more last year when building that house than I ever thought I would. It was a fantastic experience. Tons of work, but the payoff was just awesome. The only problem is, if there's something you don't like about the house when you're done, you only have one person to blame, yourself.