Backfilling basement retaining walls

[masscity]

I worked in the poured wall basement business in the Detroit area. When an excavator dug the hole too deep and we didn't have taller forms with us the builder would just add a row of block to the top.

 

[BruceWard]

The wall without a return will have a 2x8 wall and a 8.25" SIP wall perpendicular to it before it is backfilled. The one with the return will have floor trusses every 16".

We will be drilling and using lead anchors to bolt down all of the wood or SIP walls.

 

[Obed]

Bruce,
That's an interesting project you have going. Thanks for posting. Like you, we built our basement using poured concrete walls when we recently built our house and I'm very glad we did. Block walls are very difficult to waterproof in my opinion.

You are doing the right thing by being very involved in your project. My experience is that many of the workers will take shortcuts if you don't watch them carefully. For example, when our roof was being installed, I noticed the roofers installing shingles over a valley that did not have any valley flashing. When I asked the roofer about it, he said he had run out of valley flashing. I made the roofers stop work for the day. The next day they came back with more flashing and finished the job.

When the roofer ran out of valley flashing, he was mostly finished with the job and was wanting to complete the job that day so his crew would not have to come back to our site the next day. So he decided to finish the job without flashing the last two roof valleys until I challenged him. It was very fortunate that I happened to be onsite at the time or we would have never known about the issue until a year or two later when the roof would have started leaking.

Inspect the work constantly if you can. I could state example after example where we had to make the workers do the work they were supposed to do. Very often, the contractor and subcontractors will not be onsite, leaving unmanaged workers to build your house however they feel like it that day. We were the general contractor for our house build. After time I learned to ask subcontractors that we interviewed how much the subcontractor would personally be onsite for our job. I found that the quality of the work tended to be much lower for subcontractors who weren't personally working beside their employees than for those who did work beside their employees.


Good luck to you and yours during this project.

Obed

 

[Obed]

Bruce,
I would also recommend having more than 1" between your framing and the ground. I believe the code book our county uses requires at least 6". Rainwater may splash off the ground onto your sills if they are close enough to the ground. Yes, you are planning to waterproof around the floor trusses. However, no waterproofing is perfect. You might want to consider that the ground will hold moisture and you may not want that moisture too close to your wood. I think I would try to take off another 6" of dirt around the front of your house if at all possible. I understand you have some challenges with the slope.
Obed

 

[BruceWard]

Obed,

Thanks for the encouragement. Looks like you built quite a house.

I think I will leave 6" of the concrete exposed with gravel starting below that. I do not plan to have material that can hold moisture near the house.

 

[mojoinco]

We are just about at the groundbreaking phase of our addition. In our county (maybe state standard) you have to have a 1' drop in the first 10 feet from the house for the surrounding soil. And drains in the foundation area. The drains can be changed/modified if an engineer signs off on it.

Not sure how much the foundation has to stick up above the immediately surrounding soil. Will have to look at the drawings. Good thing to consider -- as it is we want to drop the garden level floor 1' from the adjoining floor, unless we exceed the 4' below ground level (project creep $$ wise -- more than 4' the walk out retaining walls have to be engineered).

 

[ametcalf]

It looks like you are going to have a great house especially with your attention to detail. We built a sips house about two and a half years ago and love it. It came in at 1.45 air changes per hour on the blower door test and we are heating and cooling it (3,000 plus sq ft) for about 83 cents a day as near as we can tell. We have a lot of glass and keep the temp at 76 in the summer and 72 in the winter. It was the attention to detail that made the difference.