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Retaining wall question

Posted by melle_sacto Z9/Sunset 14 CA (My Page) on
Fri, Sep 26, 08 at 21:19

We are having a retaining wall built. It's about 50 feet in length and the height is three split-faced cinder bricks, so ~24 inches plus the cap height of 2 inches. The wall is on a concrete footing and will be topped by a wood fence so the fence posts are in the ground and come up through the wall. The wall will retain about 2 feet of soil.

My concern is about the part of the bid called "masonry reinforcement". Although we were told this would be part of the wall, it was not done. The wall was supposed to be reinforced with rebar and wire strips, but the guy decided the rebar was unnecessary so left that out of the retaining wall. I'm annoyed at this 1) because we already bought the rebar and 2)he made this "executive decision" without telling us (I was home OR he could have discussed over the phone with my husband) and did the low-lift ground to fill all the cavities and capped the wall so it might be too late for the rebar anyway.

So, what should I do? My DH is unconcerned and his plan is to not pay for the rebar/wire since it wasn't done. Is our wall going to fall down now since it doesn't have the rebar/wire?


Follow-Up Postings:

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RE: Retaining wall question

I see both a legal issue and a construction issue.

To recover from the contractor you will need to show that he breached the contract and that the breach caused you damage. If the contractor can show that the wall, even though it does not match the plan, serves the intended use as well as what was called for in the contract, then you have no damages.

The wall is a short height and sometimes a 2ft CMU wall does last for a long time before it fails, even without reinforcement. But a block wall without the steel is a weak one. In your case, the added wood fence is another factor. Wind against a 6ft wood privacy fence can exert a large force. The added pressure of a wind loaded fence is going to make that wall fail. The steel was an important part of the plan and must be done before the block is added to the footer. There is no easy way to fix this after construction.

Were it me, if the contractor deviated from the plan I would not pay him one penny for that wall and if I thought I could be successful I would sue for the return of any money already paid.

If you decide to live with it, move the fence away from the wall a few feet. And don't garden and water plants along the upside of the wall.


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RE: Retaining wall question

Luckily the payments are based completion of each stage so all we're out at this point is the cost of the rebar and that is small compared to the total cost of all the work involved.

Unfortunately it only got worse; the guy ALSO decided not to fill the blocks w/cement like originally planned and capped the wall anyway. After we discovered THAT omission and DH talked to him, the guy came back and chiseled all the caps off and said he would fill the blocks with cement even though he thinks it unnecessary.

I WAS planning to garden along the upside of the wall--specifically a vegetable garden--so this is not sounding good.

Can the rebar still be installed despite the footing being poured a week ago and the wall already built? DH told me he could buy something that drills into the concrete footing to set the rebar. He also said he could finish the wall himself at this point. We don't have experience doing this so I'm a little worried to take it on, but I feel like the person we are working with is making some unacceptable decisions.

Somehow he had really good references.


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Clarification

My DH wanted me to clarify one thing about the retaining wall/fence. The posts for the fence go down through the retaining wall and into the footing. This was why the guy thought rebar unnecessary. The posts are a little less than 8 feet apart (so there are seven posts along the length of the wall). I don't know why he thought the concrete low lift filling was unnecessary.

Thanks for the advice!


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RE: Retaining wall question

  • Posted by bahia SF Bay Area (My Page) on
    Sun, Sep 28, 08 at 12:29

I think your combined fence/wall is bound to fail over time without the rebar reinforcing, and your best recourse is to start over. The point made about the additional pressures from wind against the fence also weakening the wall are valid ones. The time to have interjected would have been before the concrete footing was poured and it was obvious that the steel rebar wasn't set in place, and the grouting of the cells with the rebar is necessary for the structural integrity of the wall. Did your construction plans also call for a continuous horizontal rebar through at least one course of wall block? This would be much harder to retrofit if it was specified but not installed with notched block that could incorporate it. A contract is a contract, and can not be unilaterally changed without prior consent of both parties, but as it sounds like you have already paid for most of the work, you don't have much recourse except to take the contractor to court.

If you can't resolve this with the installer, be prepared to see it fail over time. I would also consider filing a complaint with the state licensing board/Better Business Bureau, or use this as a negotiating point in trying to get the contractor to do it correctly at his expense.


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RE: Retaining wall question

I remember the big storms last winter taking out a lot of fences; it's disheartening to think our new wall could fail over time due to not being built properly. I talked to DH some more about it last night and he thinks if the landscaper will do the stuff he didn't originally do, install the vertical rebar now and fill the block cavities with cement, he would like to keep working with the guy. He also plans to pay more attention to the work from now on.

As far as I know, there is no horizontal rebar in the wall. I will look down into the wall when the sun comes up and check. The footing has horizontal rebar in it but I'm not sure of the purpose. I've been regretting this type of retaining wall and wish we had just gone with a gravity-type wall instead. Hindsight...


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RE: Retaining wall question

  • Posted by mjsee Zone 7b, NC (My Page) on
    Wed, Oct 1, 08 at 19:41

You need the rebar and wire. Make him start over.

melanie


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How will I recognize wall failure?

The landscaper came back and filled the cavities with cement and, presumably, the rebar. DH is satisfied and wants to press on. He is unconcerned about the "possibility" of the wall failing over time; I suspect he doesn't believe that the discrepancy with how it's been built is significant.

I recognize that the wall hasn't been built in the sturdiest manner but I'm not going to fight this fight with my husband. He and I have too many fights over projects and I'm not going to fight over this one too.

Now I'm wondering what I can expect regarding wall failure. Will it fall completely over into the street one day due to the force of the soil it's retaining and the wind? Will the joints between the cmu's crack? What exactly occurs that indicates failure and can the "when" be estimated?


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RE: Retaining wall question

It's difficult to predict the life span of your wall. A major unknown is how the fence upright supports are integrated into the wall and if they extend into the footer or below.

If I understand your first post, the block cavities were originally filled with dirt. I have a hard time believing the contractor removed all that dirt and replaced it with concrete unless I saw him do it. I would probably dig down behind the wall and drill through the block to see what was in the cavities near the footer.

With all the unkowns, here is my best guess. There is no steel tie from wall to footer and a major weakness is at this junction. The soil will exert a force against the wall that would over many years cause the wall to tip over. The fence will have an added force that at times will be in the same direction as that of the soil force and at other times the fence force will counter the soil force, but only in the area of the fence supports.

The effect of the live load from the fence will cause hairline cracks between wall and footer beginning at the fence support and then elongating. The fluctuating forces will also lead to vertical cracks through the wall somewhere between the fence supports and the mid point between fence spans. When the cracking reaches a critical point the wall will begin to move. If the failure occurs in the spans between fence supports, it will likely be a slow failure. Failure at the fence supports in a wind storm where the wall blocks separate near the supports could be sudden.

Expect the cracks. Watch for any shift or movement from vertical or any irregularity in the wall face. Be prepared to make repairs. One to two years for beginning cracks. Two to eight years to first wall movement.


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RE: Retaining wall question

pls8xx thanks for your estimate. I can clarify a little bit here.

The fence upright supports are really long fence posts that are part of the fence and go through the retaining wall blocks, below the footer. My DH saw those being installed, that's why he knows they are deeper than the footer. I think he said they are incorporated less than every eight feet along the wall, so maybe there are seven posts along the length of the wall.

The block cavities were originally filled with nothing. You could look down through them and see the cement footer. Yikes!!!

My biggest fear is that one stormy day the entire wall will tip over, smashing any car or person that is next to it. Sounds like the failure won't be quite so dramatic. That's a relief. If we end up re-doing I think we'll do a gravity wall instead and NOT hire it out.


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RE: Retaining wall question

A future DIY project? I don't guess this would be a good time to tell you that being in a warm climate you could have done a poured in place concrete wall for around a $1000. It's easier than a SRW if you can get a concrete truck to the area.

Anyway, if the wall starts to give you trouble, come back here and we'll work out a repair. Lots cheaper than a new wall. Just don't let it get too bad before you fix it.


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RE: Retaining wall question

The traditional way to point this type of brickwork is to rake out the joints to a depth of at least 25mm (1 inch), you can use a small cold chisel for this or an angle grinder but the mess caused with an angle grinder has to be consisered as someone will have to clean up. The best mix for the pointing is a 6:1:1 mortar (6 sand : 1 hydrated lime : 1 portland cement) if you want it the normal grey colour but if you want to have coloured pointing use a 4:1 (4 sand :1 portland cement) plus the colour. All the mortar colours act as a plasticiser so there is no need for the lime or fairy liquid. Fairy liquid was banned in the 1960s as a plasticiser.

Here is a link that might be useful: Brick pointing


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