Retaining walls

[rokhunter]

I'm looking at building a 3' retaining wall to level off a slope behind the house. Running favorites right now are railroad ties, or cinder blocks. I've got zero experience with cement & whatnot but the cinder blocks seem the longer-term option.

Anyone have thoughts, inputs and suggestions?

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[CaveCreekRay]

I have done some masonry work and I have learned a lot by watching people who claim to be professionals yet repeatedly do a poor job. Block is doable but, it's a fair amount of work if done right.

IF you decide to do block, there are a boatload of good videos online to show you how to set block. If you can read a "recipe" on how its done, you might surprise yourself with how nice it turns out.

Block requires a good footer (concrete against ground) to set the first row of block on. A strip of rebar in that is always good insurance.

Plan on grouting (filling) the wall with concrete to give it strength. Grouting is done a day or two after the blocks are set and the cap of the wall is just grout shaped with a cap tool. That will take a mixer at least because the wall takes quite a bit of concrete to fill. Ungrouted walls have little strength and temp changes along with water penetration, and nearby loads like heavy rain, will pop them. Plan on laying in a row of rebar along the top of the wall for added strength. When the wall is up and done, coat it in a couple rolled on layers of asphalt water stopper to prevent efflouresce. Plan on 2" drains every ten feet along the base and either bag the dirt side of the drains with landscape cloth or bury them in gravel. Cap the downhill side with perforated drain caps to prevent critters from making those drains home.

 

[dirtydeed]

Lots of options, but, I'd stick with engineered wall block. Especially if it will be visible. These blocks are engineered to batter back into the slope by using mechanical means (pins or the block themselves will have a lip). You'll need lots of drainage stone and may want to use drain pipe and geo-textile fabric behind the wall as well.

I've found that most RR tie walls don't last (if they aren't installed correctly). They need to be anchored into the slope using dead-men (either timbers or chain/spike). The other issue with timber retaining walls as that they just don't drain well enough. You may be ok with only a 3 foot wall built from RR ties, but I'd still make sure they are anchored and backfilled with drainage stone.

Plenty of on-line and youtube instructional videos if you aren't familiar with installation. Most block manufactures will offer extensive installation guides as well. Not sure where you're doing this but permitting/ inspections may be required (I know, not what you want to hear).

 

[CaveCreekRay]

DD is right! Much less work and you can get the materials delivered for a reasonable fee. Set-up is far easier and the work goes far faster. Make sure you have a couple friends who work for BBQ and have a couple bottles of ibuprofen handy.

 

[Lil Foot]

Lots of options, but, I'd stick with engineered wall block. Especially if it will be visible. These blocks are engineered to batter back into the slope by using mechanical means (pins or the block themselves will have a lip). You'll need lots of drainage stone and may want to use drain pipe and geo-textile fabric behind the wall as well.

I agree with dirtydeed. I don't have a lot of experience, mainly assisting others with building small walls or replacing a failed one of another type. These lipped blocks impress the hell out of me, especially the larger ones. Take care setting them (absolutely no debris between them and level) and it will take a quake to move them.
https://www.homedepot.com/p/Pavesto...VoRx9Ch1wDgi0EAQYAyABEgL-f_D_BwE&gclsrc=aw.ds

 

[dirtydeed]

Set-up is far easier and the work goes far faster.

ditto. 6"-8" base of crushed/tamped stone, then set your first course (it needs to be mostly below grade...ie. you will bury your first course). Then you're off and running. Back fill with stone after every 2 or so courses. Glue top course with exterior construction adhesive and it should outlast you.

 

[rokhunter]

I like those lipped stones as well, but was turned off by the cost ($2500+ just in stones) and most seemed manufacturer-limited to 26" or so max wall height, and I need 36". Thank you everyone so far for the info!

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[Lil Foot]

manufacturer-limited to 26" or so max wall height

That's odd, I have seen them 30'+ in several places.

 

[Acmeecom]

Get the first course laid start to finish absolutely level and each first block level front to back.

 

[jajiu]

I agree with the H.D. wall stones. When I moved into my house almost 30 yrs ago, I used landscape ties for the areas that needed to be leveled. The front yard is still holding up but leaning forward a little (I did use dead-men) as that was the thing to use. Now I use the wall stones, and I have ripped out the ties in some areas and replaced with the stones. Once the first course is in and level, it just takes stacking and back-filling. Easy, but back breaking.

 

[North Idaho Wolfman]

It's a matter of cost of material offsets:
1: Doing it again because you used cheap inferior material.
2: Lower skill level required to get excellent results.
3: Lower additional material requirements.

While simple cheap concrete block sounds good it will fail over time if not done the way required, IE foundation, rebar, concrete fill, pinned back into the slope, and proper drainage.
It also takes a good skill set to be able to set block properly, and it's not fast unless your very skilled.

Railroad ties or any landscape timber will also fail over time, they always do, and even quicker if not properly installed, IE rebar pinned to the ground, back into the slope, and to each other.
Most people do not have the proper tools (BIG DRILL) and long auger, and if you've never drilled a RR tie, they don't drill easy.
Most RR ties you can get now are junk, they are pulled off rail lines and are on there way out that's why the RR changed them out, and new RR ties are super expensive!

This solid block states 36" ( higher walls require hollow blocks and rebar and concrete fill) and at $605.58 a pallet it's not the work price out there.
there are smaller lighter versions of these too.

https://www.homedepot.com/p/Pavesto...k-45-Pieces-30-2-sq-ft-Pallet-83675/202365278

 

[dirtydeed]

I like those lipped stones as well, but was turned off by the cost ($2500+ just in stones) and most seemed manufacturer-limited to 26" or so max wall height, and I need 36". Thank you everyone so far for the info!

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Yes, you'll find that lipped blocks do not allow for much height. They are intended to be used for fairly low walls (since they are "gravity walls"). They work better when glued. The better option is to use hollow core (either pinned, or geotextile reinforced). The hollow cores are obviously lighter to handle and are filled with drainage stone during installation as they add mass and also aid in drainage.

A poorly constructed wall/poor materials can fail easily following heavy rain events. I've seen them, and have redone many when I had my landscaping business. Trust me, you do not want to have to redo one. It's quite a bit of work and creates a real mess.

If you're considering these as an option, my suggestion would be to ask a knowledgeable landscape supply owner what they recommend for your area/soil type.

Best of luck to you.

 

[GreensvilleJay]

My retaining wall is made from 6by6 PT timbers, 12' long each. About 40' total length. 4 rows high, then stepped back 3' and another 4 rows high. Laid gravel as a bed, gravel behind for drainage.Used 4 or 5 'deadmen' as well.
I must have done something right as it's 31 years old and STILL straight and plumb ! Wife grows veggies and flowers in the two 'beds'. Lower 2 courses are pinned into ground with 8 or 10' ground rods, every 6'.

Jay

 

[dirtydeed]

My retaining wall is made from 6by6 PT timbers, 12' long each. About 40' total length. 4 rows high, then stepped back 3' and another 4 rows high. Laid gravel as a bed, gravel behind for drainage.Used 4 or 5 'deadmen' as well.
I must have done something right as it's 31 years old and STILL straight and plumb ! Wife grows veggies and flowers in the two 'beds'. Lower 2 courses are pinned into ground with 8 or 10' ground rods, every 6'.

Jay

Sounds like you did it right...By using two low (2') walls instead of one 4' wall. There's a lot more push behind a 4' high wall.