Small retaining wall - correct/rebuild

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Old 09-10-14, 06:34 AM
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Small retaining wall - correct/rebuild

I am moving next week and one of the first projects I need to tackle is to correct a badly failing masonry retaining wall. I am totally inexperienced and ignorant in this area, but optimistically hoping to do it myself. I'm wondering if it's realistic or not and if so, what my plan of attack might be.

It's a small wall, 2-3 feet high and maybe 5-8 feet long. See the picture attached.

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Any feedback is appreciated. Thank you.
 
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Old 09-10-14, 07:11 AM
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Absolutely you can do this yourself.

You'll need to remove what's there and cut back the hill as well as decide whether you want a solid wall with a concrete footer or a segmental block wall. The latter would be my choice.
 
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Old 09-10-14, 07:40 AM
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I almost always use structural retaining wall blocks. They are DIY friendly and since there is no concrete to pour the project can be done in small stages as time permits. Do not buy blocks from your big box home center. You want engineered, structural retaining wall blocks which are much bigger & heavier and have a mechanical method to lock the blocks together.
 
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Old 09-10-14, 07:41 AM
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Thank you, I was hoping that it would be as simple as that.

I was hoping to salvage a lot of the blocks and re-use them for the rebuild. But I will have to do some research on the best materials to do the job.
 
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Old 09-10-14, 08:01 AM
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Just from the picture, I would consider everything you have now to be waste and I would buy all new materials.
 
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Old 09-10-14, 08:26 AM
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I agree with Mitch! There are very good instructions for building a retaining wall online. The biggest secret for a retaining wall is a solid foundation. I personally would dig down 16" and twice the width of the block. Back fill 12" with #1 crusher run fill and compact it as much as possible. set your first block below the finish ground elevation and build from there. As you install the blocks vertically, you back fill and compact behind the blocks. Use a level to keep the block level and plumb. Wall should last you your life time.
 
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Old 09-10-14, 08:45 AM
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Interesting. So when you say to dig twice the width of the block, and place the first block below ground elevation, do you put it in the middle of the footer with a space on either side, or at the front?
 
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Old 09-10-14, 08:55 AM
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Generally you want the retaining wall to be in the center of the footer so the footer can evenly distribute the weight of the wall. This is critical to prevent it from sagging and for one side to sag causing the wall to lean. Burying the bottom course at least partially underground offer lateral resistance to prevent the wall from being pushed sideways.
 
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Old 09-10-14, 09:20 AM
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Is gravel alone sufficient for the backfill? I've seen in some instances, some sort of metal bars are placed there.
 
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Old 09-10-14, 09:50 AM
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Have you done concrete projects before. Do you have a trade where you use level. Are you n excellent physical condition. Are you smart enough for instanteous learning. If not do not attempt. Get the blocksthat dont need mortar.
 
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Old 09-10-14, 09:56 AM
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No, no, yes, yes.

There is a first time to try anything.
 
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Old 09-10-14, 10:43 AM
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we usually build w/versa-lok as their plant's the closest so freight's lower,,, apron/vest stores sell their stuff retail but its rare for a pro wall bldr to buy from them,,, mostly its h/os & diy'ers,,, for what you need, the apron/vest store's the place to buy 'em,,, they're like legos
 

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Old 09-10-14, 01:21 PM
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A butchered block wall will scare buyers but i want an after pic.
 
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Old 09-10-14, 01:53 PM
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If you can wait a few weeks, I promise you an after pic.
 
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Old 09-10-14, 02:04 PM
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For your situation, you could do a custom job by also getting rid of that tipping timber planter bed retainer, and use the same block to build both a new planter and the full-height wall behind it. Tie them together with a curving front corner. Just don't make it too pretty, or all the neighbors will want you to build one for them, too.
 
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Old 10-10-14, 08:00 AM
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Gentlemen, as it turns out I have not gotten around to building my wall yet. After closing on the house it got bumped down the priority list by a multitude of other items.

However, I have finished dismantling and excavating for the new wall. I've decided against Vera-lok, and am going to use concrete blocks.

My new question is the following. For a mortar block wall (blocks are pretty darn heavy), is it necessary to bond with mortar, or could one of the stronger types of masonry adhesive be sufficient, assuming proper footer, drainage and backfill are in place?
 
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Old 10-10-14, 09:51 AM
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As long as you are using a plain concrete block wall, you must have a concrete footing and use mortar to bond the block to the footing and to each other. - In other words, you have to have some masonry skills. You also have to face the problems with frost heaving and cracking of the joints in the future from frost heaves and weather conditions.

I you use the segmental retaining wall (SRW) block, you do NOT use a concrete footing, but set the first course dead-level on a compacted gravel base. It is not necessary for the wall to be at the center of the base, because the compacted base is meant to provide a firm working place to start. The first level of the block should be 4" to 6" below the ground level. After that, just stack the block and the "shear lugs" (usually on the back rear or front top - depending on the brand) take care of getting the slight "batter" to the face of the wall to increase the stability. Most brands have solid 1/2 height cap block for finishing that is compatible and is attached to the top full height block with globs of a silicon flexible adhesive. The block allow the wall to be used on both straight walls or curved walls. Never use a concrete footing or mortar with SRW block because it is intended to be a "flexible" wall that can move with conditions and not a "rigid" wall that can crack and move.

SRW walls can usually built 4' to 5' without any engineering required, but can goo as high as 30' with engineering.

Use what you are comfortable with, but definitely do it right to get the most out of your efforts.

Dick
 
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Old 10-10-14, 10:00 AM
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Poor choice of product. Will require (a lot) more work than going with a dry-stack product, won't look nearly as good, and will require ongoing maintenance to repair the cracked mortar joints when the wall is subject to soil pressure from behind.

But it's your wall, and you can't say you weren't warned.
 
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Old 10-11-14, 05:32 AM
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as bdge sez, its YOUR wall,,, both bdge & dick know their stuff & they offer freely that for which they once charged appropriately,,, you, otoh, own the land AND wall - your choice,,, buying inappropriate materials now @ a lower $ will cost mucho more $ later on
 
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Old 10-17-14, 07:30 AM
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I hear what you are saying. The thing is, these materials aren't just cheap they are free, I already have the blocks. The expenses have been racking up with the new house, as they do.

I've decided to go this way because I already have the materials, and make do the best I can. If the wall fails in a few years, I should be better positioned to do it better at that point.

But in the meantime I think I can whip something up that should last at least a few years.
 
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Old 10-17-14, 02:12 PM
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That's funny. A 8'x3' segmental retaining wall that doesn't need a concrete footer or mortar or as much excavation would have cost you $100 for the blocks. And you'd have also needed about a half yard each of road base and drainage rock.

As for mortar vs adhesive. If you try to use adhesive, you are going to be pulling your hair out. Every single block needs to be perfectly flat and clean and level along all four sides or you will end up with a hideous looking wavy wall. The time to get that kind of precision is absolutely not worth it. Forget that the adhesive will end up costing more.

You've got nothing but excellent advice from everybody here and you haven't actually utilized any of it.
 
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Old 10-18-14, 04:07 AM
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as you'll often discover in home ownership, ' free ' is usually the most expensive,,, ' often discover ' as you'll likely make the same mistake again & again,,, imn-s-hfo we always find time to do things over the right way whenever there wasn't time to do it right the 1st time - wonder why that is ?
 
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Old 10-18-14, 09:50 PM
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I can't imagine the amount of effort he's going to have to put in to cleaning the mortar off those blocks, just to be able to reuse them. That most certainly makes them not free.
 
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Old 10-27-14, 05:29 PM
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Basically engineered and planned it myself, based on internet research and a few tips from a friend. Footer with gravel and sand on top. Back filled with #2 gravel. Dry stacked at the bottom, then used adhesive for the top half of courses. There are some big enough cracks between the blocks for water to get through.

Agent008, you were dead right, cleaning the blocks was the most time-consuming part by far. It wasn't hard, just tedious. Getting the bottom course level on the sand was the most difficult. About a month of working 4-5 hours every weekend.

We will see if it stands the test of time, but at the moment I feel great about it.
 
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Old 10-27-14, 10:35 PM
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Good job finishing the project and thanks for the pics.
 
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Old 10-28-14, 05:29 PM
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Nice job! You should have no problems!
 
 

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