# replacing RR tie retaining wall with blocks



## seagal (Jun 28, 2012)

We have a 2' high RR tie retaining wall surrounded by a 50" wide concrete sidewalk than a pool. We want to replace the ties with blocks, but are not sure how to go about it. When we take the ties out, will the dirt stay in place? Also, since the blocks are wider than the ties, how do we skim off enough of the soil to make up for the difference? Thanks!


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## andybeck (Jun 18, 2012)

I am not real experienced with this but I have built a couple walls. Unfortunately it will not be as easy as taking out the ties and stacking the blocks. With retaining walls, it is important to do it right or the mistakes will be very noticeable and annoying. 

If you have room to bring the wall out a couple feet, the easiest approach would be to dig a channel about 12 inches deep. Fill and compact the channel with packer gravel and lay your first row of blocks. Make sure that they are perfectly level across at least 3 blocks. If you don't, the unevenness will increase as you stack vertically. Stack you wall to the height that you want and remove the railroad ties. In the space that is left, fill with gravel and compact as you go up. you don't need gravel all the way up but I would go at least half way up a 2 foot wall. You can top it off with dirt and grass or mulch or whatever you choose. 

If you don't have room to bring the wall out, You will need to excavate some of the dirt behind the wall because it will probably collapse. Even if it doesn't collapse, you will still need to dig your footer for the blocks. 

Again, I am not an expert on this but hopefully someone else will chime in.


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## AGWhitehouse (Jul 1, 2011)

The dirt will likely NOT stay in place. Take the time and little extra $ now to do it right or you'll be doing this process all over again in 5 years...


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## DexterII (Jul 14, 2010)

Although they share common ground (pun intended, or not, as you wish), you actually have two projects; the first being demolition of the existing wall, and the second being the construction of the new wall. As AG said, the dirt around the ties is probably not going to stay in place, but because, as Andy mentioned, the blocks will require proper soil preparation, which very unlikely took place before the ties were put in place, you cannot simply remove one and immediately start on the next. Rip the old ties out, haul them off, and you're done with with "phase one". Then lay out what you want, set some grade stakes, and you're ready to start removing soil for the bed that you will lay for the blocks, some of which will be easier to dig, as it will be the previously disturbed soil that was around the ties.


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## KevinPh (May 25, 2012)

More than likely the soil will move. You will have to shore it, the same way they do when digging an excavation for a foundation.

Remove the top two railway ties for the first 16 ft. section. Excavate the soil under the existing concrete slab/walk for an 8 inch depth. Even out the soil under the concrete slab so that it is vertical. Set in place 2 x 6, 2 x 8, or 2 x 10 lumber so that it holds the soil under the concrete slab in place. Where the shoring lumber joins, nail a small piece of lumber over top that overlaps the two pieces. You can further support it, if need be, by installing 2 x 4's vertically every 4 ft.

Continue doing this until you have removed all of the wood ties. The result will be that all the soil under the concrete slab is kept in place by the shoring lumber. - and it will be recessed by approx. 4-6 inches.

Now dig down for the new concrete block retaining wall. Whatever product you choose will have specs for how far below grade you should lay your first course - for a 2 ft. wall it will likely be 1 ft, but check the manufacturer's website. Lay the concrete block in place and then backfill up to the top of each course as you go. Don't forget to remove the shoring, starting from the bottom and working up. If you are laying a perforated PVC pipe for drainage, that should be done before removing the shoring. Continue placing the concrete wall, installing backfill and removing shoring until the top level. If you are in an area subject to freeze and thaw, you should put expansion joint material between the coping stone for the retaining wall and the concrete slab - you can get it from a building supply store.

I don't know what the soil condition is on your site, but you may want to have it analyzed before you begin as a precaution. On the other hand, if there were no structual problems with the retaining wall you are replacing, then you are probably good to go.

Hope this helps

Kevin 
home-additions-startup-guide.com


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## seagal (Jun 28, 2012)

Thank you for all the replies. We're replacing the ties since they are basically rotting away! Our soil is mostly clay and rocks and usually does freeze here on occasion. Drainage is a must I assume since we have a sprinkler system that runs though the garden bed there. I think after reading all the emails, we can handle the project. It wiull be nice to finally not have dirt oozing from the bottom of the ties after it rains! If we run into snags, we know where to come!! Now to find some inexpensive blocks will be our first step.


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## teamcampreder (Jul 23, 2011)

I am going to refer you to my thread from when I did mine.

http://www.diychatroom.com/f49/big-dig-redoing-retaining-wall-around-my-driveway-140431/

Long story short, if its only two feet, you don't need to worry about the Geogrid that I did in that thread, but you do need have a vertical layer of drainage gravel behind the wall, along with a drainpipe for water to exit. You are probably going to end up with some extra dirt, i recommend craigslist, its easy to give stuff away for free.

I would find a reputable landscape company in your area, and work with the salesperson there. They will help you pick out a block, and the block manufacturer will give you all the specs on how you should do your wall. I had an excellent experience with versalok, both the company and the product, but I believe they are pricey.

Don't do a crappy job, because otherwise you will be doing it all over again in a few years.


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