At Home In The Woods

[Obed]

I'm paranoid in three areas of this house building project:

• plumbing drains
• concrete
• waterproofing

When my wife and I were house shopping, we saw house after house in this area with musty basements, and significant foundation settling evidenced by large slab and brick cracks. I would say that at least 50% of the houses with basements that we looked at had serious settling issues. One home seller told us he had paid an engineering company many thousands of dollars to drive steel piles in the ground and jack up his foundation. It was sad, particularly because you could tell that this man was the type of person who takes really good care of his stuff. In addition, I've lived in houses with toilet overflow issues due to drain issues.

We are doing the best we can to avoid these problems in our house. We told our construction manager to leave the tops of all the basement plumbing pipes uncovered. Once he has all the gravel under and around the pipes but not over the pipes, we will put a level on all the pipes and give approval for covering the pipes the rest of the way. He doesn't like us inspecting the work this way. However, my experience with people has been that the quality of work tends to go up when people know their work will be inspected.

 

[Obed]

Here is a picture of what has happened to more of our trees than I like to think about. Before backfilling began, I nailed some scrap 2x4s to a couple trees in the path of the backfilling equipment in the hopes of preventing the bark from getting skinned off of them too. As soon as possible, I want to get the dirt off of the roots of the tree in the picture. We have a number of other trees with roots that have also been covered with dirt. We love the trees and don't want to lose them.

 

[dcyrilc]

Sadly, here is a picture of what has happened to more of our trees than I like to think about. Before backfilling began, I nailed some scrap 2x4s to a couple trees in the path of the backfilling equipment in the hopes of preventing the bark from getting skinned off of them too. As soon as possible, I want to get the dirt off of the roots of the tree in the picture. We have a number of other trees with roots that have also been covered with dirt. We love the trees and don't want to lose them.

Trees are great, but if they start having problems - take them down. You can always replant.

 

[2manyrocks]

Sorry, but it appears I'm too late to suggest wrapping the gravel backfill in fabric to keep it from silting up.

After your plumbing drains failed, I guess I'll ask if you've tested your drain lines? I only ask because mine were going uphill and had to be redone. You'd think these guys would check while they could still easily be corrected.

 

[Obed]

Here in the midwest we only have sand put down before a slab is poured. Why is gravel used for this? Can you put sand around your plumbing lines to help against any movement?

I don't really know the answer. That's how the construction manager is doing it. I assumed that it was standard practice around here.

Obed

 

[Obed]

Trees are great, but if they start having problems - take them down. You can always replant.

Cyril, that's a huge tree. Did it hit your house?

 

[Obed]

Sorry, but it appears I'm too late to suggest wrapping the gravel backfill in fabric to keep it from silting up.

After your plumbing drains failed, I guess I'll ask if you've tested your drain lines? I only ask because mine were going uphill and had to be redone. You'd think these guys would check while they could still easily be corrected.

Our soil is solid red clay. It is not sandy or silty. It clumps together. I'm not worried that this type of soil will penetrate through 4 feet of gravel like sandier/siltier types of soil will. If any silt does make through the gravel, we have fabric over the drain tile to keep the drain tile from clogging. At least that's what I hope. Could be wrong but not much can be done at this point.

No, I did not test the drain lines. The grade of the excavation around the basement was such that I'm pretty sure it all goes downhill so I believe we're ok.

Obed

 

[dcyrilc]

Cyril, that's a huge tree. Did it hit your house?

Nope. It was my mothers!

 

[dave1949]

I don't really know the answer. That's how the construction manager is doing it. I assumed that it was standard practice around here.

Obed

Normally about 8" of clean, washed stone is used below a slab when you have drainage tiles running under it. Gives the moisture a pathway to get to the slotted tile, sand can't do that as well. Without drains, sand is fine, but it still needs to be compacted. Either stone or sand should have a good vapor barrier between it and the bottom of the slab. Two or three layers of 6 mil black poly is a good choice for that barrier. This needs to go down before the rebar is layed out. In cold regions, 2" of extruded polystyrene would be layed over the vapor barrier - under the rebar.

It's possible you are in an area where not much 'good' foundation work is done. That may explain why you saw so many musty basements while house hunting. It happens. If there are lots of damp basements in your area, you should consider using drain tiles under your floor slab that lead to the outside on the downslope side of your building area.

Yes, you should have covered your gravel above the french drains with filter fabric. I sort of wish you would get ahead of the work with your posts, nobody likes to tell someone they did something wrong or missed a step.

There are many people here that can give excellent advice for building just about anything, anywhere. If you aren't 100% sure of how to do something, just ask ahead of time. Don't want to sound like a grouch.
Dave.

 

[2manyrocks]

I would test the french drain lines and any other drain lines before you cover them up. It may seem like one more thing when you're probably overloaded, but I would test them or at least look at the outflow point when it's raining. I kept looking at our drain lines thinking that there should be more water pouring out and then realized that they weren't pitched correctly....after we had gone a lot further than you have.

Just want to save you the grief that I know about from bad experience.