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Sly
Premium Member
join:2004-02-20
Tennessee

Sly

Premium Member

[Landscaping] Store excess driveway gravel and dirt under the deck

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I'm wanting to put in a cobble stone driveway to replace the gravel driveway I currently have. I was thinking about storing it under the deck on the front of the house. It would serve two purposes. Give me a place to put the dirt that I excavate and provide structural support for the retaining wall at the front of the house, which to me looks like it could use the extra support.

Does anyone see any problem with this? Do I need to drylock the wall before I put any dirt under there? Structurally do you see any problem with placing dirt up against the house? There is already dirt on the sides. It's just the front under the deck is dug out...

mix
join:2002-03-19
Romeo, MI
GL.iNet GL-B1300
Netgear CM500

mix

Member

said by Sly:

Give me a place to put the dirt that I excavate and provide structural support for the retaining wall at the front of the house, which to me looks like it could use the extra support.

This deck, which looks cobbled together with tree limbs, actually has a retaining wall in front of it?
Kearnstd
Space Elf
Premium Member
join:2002-01-22
Mullica Hill, NJ

Kearnstd to Sly

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to Sly
Hmm putting dirt under there could rot the posts especially since some of those posts appear to be tree limbs.

Sly
Premium Member
join:2004-02-20
Tennessee

Sly to mix

Premium Member

to mix
Actually the deck is held up with 6x6 beams. The retaining wall is supported by concreted logs bolted to the beams (not my doing). In front of the wall is currently a small raised flower bed filled with mulch. This is an old picture from 2007 but the deck is still the same. What I would like to do is fill in under the deck with unneeded driveway gravel and dirt.
Elthesh
join:2001-12-01
Fort Lauderdale, FL

Elthesh to Sly

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to Sly
I could be off, but it looks like that retaining wall was on the verge of completely failing at some point in the not too distant past and was then shored up using, ummm, questionable methods. It honestly still looks to be on the verge of failure at any moment due to that jerry rigged repair. Personally, I wouldn't put anything under there as it would likely cause more problems when that wall fails.

In my opinion, it looks like a disaster waiting to happen. As I said, I could be wrong, but just looking at that scares the heck out of me and I wouldn't want to be anywhere near it till a professional evaluated that thing.
Tig
join:2006-06-29
Carrying Place, ON

Tig to Sly

Member

to Sly
Tell us about the wall of the house. What is it made of? How long is it? How deep would it be once you finish back filling?
The timbers bracing the retaining wall will be redundant if you backfill, so they are irrelevant until the backfill question is solved.

DarkHelmet
join:2014-02-21

DarkHelmet to Sly

Member

to Sly
Grab a gallon of wood preservative and paint the bottoms of all the wood. Then throw the dirt in like you want.

Bamafan2277
Premium Member
join:2008-09-20
Jeffersonville, IN

Bamafan2277 to Sly

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It could be the camera angle making the retaining wall look like its buckling.

mattmag

join:2000-04-09
NW Illinois

mattmag to Sly

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Actually those logs are bolted to the supporting posts, not the beam, which I am sure is not a good situation at all. Those posts are designed to support a vertical load, and placing such a side load on them is asking for trouble.

I know it isn't what you asked about, but I'd have someone fix that issue pronto.

Sly
Premium Member
join:2004-02-20
Tennessee

Sly to Bamafan2277

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to Bamafan2277
Correct. It's a bad camera angle. The wall is not bowing out as bad as it looks in the picture. There is one place that is bent back if you look for the re-bar, but there is an intact sheet behind it that is not bent.

Overall it sounds like (and I agree) that I need proper structural support under the deck. The house was built in 1988 and the original owners rushed the contractors to finish. They obviously took some shortcuts.

If I back fill, that should give the support I need. But I'm wondering if they didn't back fill for a structural reason. The walls are made out of block and coated with a mortar. I'm not exactly sure how thick they are. They appear a least 16 inches. The wall is about 35 feet wide.

What if I didn't back fill all the way and instead filled up to the house a depth of 3' and then sloped the back fill upward toward the retaining wall? So rather than putting the entire load against the house, I could only put about 3' of dirt against it and hopefully provide the support the wall needs. At least that way there would be less bracing needed to finish supporting the retaining wall...

My original goal was to find a place for some driveway gravel/dirt. I didn't realize until recently what condition things were in under the front deck... Hopefully I can kill two birds with one stone.
lutful
... of ideas
Premium Member
join:2005-06-16
Ottawa, ON

1 recommendation

lutful

Premium Member

said by Sly:

So rather than putting the entire load against the house, I could only put about 3' of dirt against it and hopefully provide the support the wall needs. At least that way there would be less bracing needed to finish supporting the retaining wall....

Just an idea ... you could use plywood and lumber to make sort of a trough shape with sloped walls on both sides. Support the trough walls with a few fence posts and floating concrete footings.

Now, weight of your rubbish will not push against the house or retaining walls.

ArgMeMatey
join:2001-08-09
Milwaukee, WI

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I've seen worse. But you do not want to transfer the load of the driveway area onto the house foundation unless the foundation is rated for that load, and adding fill in this space could do that. I am not saying it would do that, but it could do that.

The best course of action is to have a licensed structural engineer review what's there and give you an opinion on what (if anything) should be done to ensure the integrity of the retaining wall. I don't know if you've ever worked with a structural engineer, but for situations like this, the ones I have worked with could eyeball stuff and tell me quickly what was wrong, then measure and photograph, and write specs for what to do to fix it.

In other words, you are going to get the usual online forum response: A bunch of people with no interest in the result say "no problem," others say "evacuate now," and you can tally a crowdsourced decision from those. Or, you can bring in somebody who gets paid to figure it out, and incurs liability if he gives you bad advice.
PrntRhd
Premium Member
join:2004-11-03
Fairfield, CA

PrntRhd

Premium Member

Agree, the piling of sloping soil against the wall can have unintended effects. Like affecting where water goes causing leakage into the lower story and possibly weakening the foundation.
Tig
join:2006-06-29
Carrying Place, ON

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1 recommendation

Tig to Sly

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Your local building code will have a spec for the backfill depth.
For your convenience here is a segment of our local code. We also have frost push to consider so the spec should should have no problem meeting Tennesee code.
»akloc.files.wordpress.co ··· 9-15.pdf
See table 9.15.4.2.A
The lateral support at the top requirement can be satisfied by anchor bolts interlocking the wall to the floor structure above.
If you have 12" blocks and top wall lateral support you are good to over 7'
Don't forget to water proof that wall first.

Sly
Premium Member
join:2004-02-20
Tennessee

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That's awesome advice. I've decided to forego placing any back-fill there until I have it evaluated. Currently I have zero moisture issues downstairs. The house is quite dry no matter how hard it rains. I'm afraid that if I added soil it would change that.
Critsmcgee
join:2011-12-02

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said by ArgMeMatey:

I've seen worse. But you do not want to transfer the load of the driveway area onto the house foundation unless the foundation is rated for that load, and adding fill in this space could do that. I am not saying it would do that, but it could do that.

The best course of action is to have a licensed structural engineer review what's there and give you an opinion on what (if anything) should be done to ensure the integrity of the retaining wall. I don't know if you've ever worked with a structural engineer, but for situations like this, the ones I have worked with could eyeball stuff and tell me quickly what was wrong, then measure and photograph, and write specs for what to do to fix it.

In other words, you are going to get the usual online forum response: A bunch of people with no interest in the result say "no problem," others say "evacuate now," and you can tally a crowdsourced decision from those. Or, you can bring in somebody who gets paid to figure it out, and incurs liability if he gives you bad advice.

That's great advise aside from that fact the engineer will charge $1,500 to give you help and back it. If that's not an issue by all means get an engineer involved. What happened before engineers were common? I'm sure this happened before them.

ArgMeMatey
join:2001-08-09
Milwaukee, WI

ArgMeMatey

Member

said by Critsmcgee:

What happened before engineers were common?

Another good point. Since these walls rarely fail catastrophically, when things start falling apart, you would just fix it.

The point is that if he put the fill under the deck, nothing would happen for "a while," but after some period of time stresses will start showing up. All retaining walls will fail eventually. The question is whether he wants that to be five years, a decade, or 100+ years.

We should seek balance between cost and benefit. If the cost of a structural engineer seemed like too much, I would look at the cost to fix whatever bad might happen while I owned the place, or how much it would take off my sale price, and if that was less than the cost of the engineer, I might just live with it.

Out in my yard, if I build a wall that would need some re-work in 15 years, that might be a better option than spending three times as much to get a wall that would last 30 years. But for something next to the house, I do want something that's good for 40 or 50 years, because when prospective buyers perceive a "foundation" problem that's the last I'll see of them.

DarkHelmet
join:2014-02-21

DarkHelmet

Member

said by ArgMeMatey:

...because when prospective buyers perceive a "foundation" problem that's the last I'll see of them.

That's just leverage against you. I love to see problems in properties before I buy them.