Entry retaining wall 2

This rock retaining wall is slowly sinking into ground over the last 15 years. Instead of taking it all out and building a block wall would it be possible to just push the large rock further into the small slope and building a retaining wall in front of it with posts driven below frost line and treated lumber to hold soil back?

 

[r13]

Remove the dirt pile and build a new wall - as suggested by your name.

 

[DoItRightTheFirstTime]

Thank you for the reply. That was my first thought but was wondering if it would cause the steps and top landing to sink further if all rock and dirt were removed?? Also, would you have to put a retaining wall under the top landing area to below frost level and back step blocks down to lower level? I was thinking the main reason for the slow sinking was moisture in the ground over the years with frost heaving even though it is mostly sand there.

 

[kipfoot]

You'll also need to replace the top landing and possibly repair some damage to the framing/sheathing. It looks like the landing slopes toward the house, which may be a hint to what's causing the settlement.

 

[r13]

Can you remove some dirt from the top to expose what is under the landing and steps. I think the landing is supported on the perimeter wall, but not sure how the steps are supported. A photo from the other side will help too.

 

[DoItRightTheFirstTime]

Thanks again for the reply! I am not sure if all of my photo's are being attached but this is the situation after clearing out the stone at the top of the landing. The top landing is in perfect shape and is just as level today as the day I poured it over 20 years ago. It is a 16" deep concrete landing and soil is still tight to bottom. I had the steps done professionally about 13 years ago and the top step is still level and the others may be sloped towards the house a little. The house has a big chalet type roof and is facing South so I didnt think water would be an issue but forgot about snow melt.I think the snow melt over the years may have cause d the rocks to sink a bit and push the concrete pad on ground level causing a column to push out a bit. I want to build a few columns and stone the wall around the patio door but don't want to do it unless I cure the large rocks from sinking or pushing the concrete slab.This is why I was wondering if it wouldnt be better to just push the stones in a little to further compact and put some type of concrete footing in front to prevent any more further sliding? There is nothing attached to the house and the house does not seem damaged in any way.

 

[r13]

Your attachment didn't come up.

I didn't see any indication from your original photo too. So that's why I asked you try to peep into the space.

[It is a 16" deep concrete landing and soil is still tight to bottom./quote]

Do you have an old picture to show the original condition? I couldn't figure out where the dirt came from, and where shown sinking/settlement. Do you know how high is the ground water in your area? Also do you have good slop around the house?

 

[DoItRightTheFirstTime]

Thanks again for the reply. I have never had a drop of water in the house. The house is built on a crown of a hill and all water slopes away. I think the main problem is where the big rock sits. It looks like it may have put too much pressure on the slab of concrete that was poured later on causing it to crack. I used black butyl rubber to seal the cracks. The house was built according to the Frank Lloyd Wright shallow foundation system and never had any problem with the foundation. The water table is very deep. I do not have any old photo's I can find at this time. I thought maybe a post hole digger with tubes filled with concrete and treated lumber or steel laterally tied to them may prevent any lateral movement?? I am thinking freezing and thawing in these Wisconsin winters has cause some movement around that big rock area as I dont know what else it could be.....How could a person ever prevent moisture from going into the ground and prevent frost heaving???

Thanks again for your advice and time!

 

[r13]

Since There is no major problem at this time, it may not payback to remove the dirt, especially the rock. I think the heave might have softened the dirt to a loosen state, but not to fluid like that will slide. I suggest to protect the toe, by constructing a low stone/masonry wall (1-2 steps high), or by treated wood logs, to make it a nice looking flower bed. The roots of the plants will protect the slop too.

 

[DoItRightTheFirstTime]

Great! that's what I was thinking but do I need to go below frost level with posts or are you saying dig down a bit to get a packed level surface and just build a block wall 2 steps high and fill level with dirt and plant something in there? Do you have any good idea's on how to make that area look nice without removing all the dirt and rock?

Thanks again as you saved me lots of work and for some reason if this small wall pushes the concrete pad I am not out much. Should I leave a little space from the small retaining wall and concrete pad?

 

[r13]

Given the cold weather concern, I prefer wood logs over stone/masonry, which requires deep foundation down to frost. You can dig holes below frost and concrete the posts in, or just driven the post in if the ground permits, then use horizontal logs as barrier wall. Don't make wall too tall, so you can use smaller material to produce the better result, shall the soil slide a little to push against the wall.

Another simple material to consider will be the railroad ties with pre-drilled holes. Then you only need to driven anchor steels. By using pieces with different length, you can create a nice looking wall too. Note, the purpose of the wall is exactly the same as retaining wall, to retain the sloped dirt.

I'll replace the top few inches of the dirt with quality top soil, as well as behind the wall, to allow good drainage, not to be washed-off. You shall Leave the topmost soil 6-8" below the top of landing.

For plants, I suggest all season ground cover (no climbing type), with grass, and a few flower plants. This is the good time to start this project, enjoy it

 

[DoItRightTheFirstTime]

Thank you very much for all your advice. I think I will go that route.

 

[r13]

Wish you enjoy your project, and make Frank smile Provide us a photo when finished.

 

[BAretired]

DoItRightTheFirstTime,

Your file entitled "Top Landing" has no extension, which is the reason it can't be opened. It probably should be Top Landing.jpg. Can you fix that for us?

I am wondering whether variable frost depth is having an effect on the soil regime around the entrance. I was surprised to read that frost depth in Wisconsin is as much as 65". Of course, that would not be true every year and may never be the case adjacent to a heated home. Your rock garden retaining wall has a height of five risers at the landing, probably about forty inches, tapering down to zero at the bottom of the slope.

The stair, I assume, is resting on grade and is subject to annual frost heave. The pavement at the bottom of the stair has cracked, likely a result of frost heave. It would probably be better to be separated from the stair and rock garden so that it can heave without restraint. The slab is more susceptible to frost heave than the stair because it is at the lowest elevation and likely to be resting on moist or wet frost susceptible soil.

I can't see how a small wall as shown in yellow outline on the photo is going to achieve anything useful. If frost wants to push it, it will move.

I wonder if insulation placed judiciously over the rock pile would achieve anything useful. Hard to say, and it might make it difficult to plant anything. Hmmm.

BA

 

[r13]

BA,

The foundation of the yellow stone wall is not shown, and the depth of frost was the concern that changed my preference from stone wall to log wall, that can drive posts deep into ground with much less cost and effort.

I don't think the freeze-thaw of the dirt pile will affect the stair structurally, as it is not supporting anything, and rather, it protects the soil and structure below the stair/landing from the freezing temperature, very much as a blanket. So, I refrained from making suggestion to remove it, which is quite difficult (thinking about the size of the nice looking boulder/rock), and a lot of other works need to be done to protect the stair.

I guess OP's problem was some of the heaving soil had slide too close to the sliding door, that need frequent removal/cleaning. Thus, a short barrier wall should work to block that movement by catching the loose soil behind it. I love the planting idea, as it adds focus point to the bare entrance, and eventually will provide protection to the slop, once the roots have firmly developed.

Well, to me, it can be a fun project, I will jump in if I live the next door

 

[BAretired]

I guess OP's problem was some of the heaving soil had slide too close to the sliding door, that need frequent removal/cleaning.

I didn't read that in his comments, but you may be right.

This rock retaining wall is slowly sinking into ground over the last 15 years. Instead of taking it all out and building a block wall would it be possible to just push the large rock further into the small slope and building a retaining wall in front of it with posts driven below frost line and treated lumber to hold soil back?

In the first post, he is concerned with the rockery (which also acts as a retaining wall) sinking into the ground. To just push the large rock into the slope might help if it is preventing the slab from heaving freely. Otherwise, it would not help.

I think the main problem is where the big rock sits. It looks like it may have put too much pressure on the slab of concrete that was poured later on causing it to crack.

Settling of the big rock over the years may or may not have anything to do with the slab cracking. It is not readily seen by looking at the photograph. Another possibility is to sawcut the slab so that it is free from the large rock.

The two straight red lines in the photo below represent the edge of slab. The freehand red line encircles the dominant crack and appears to be the high point of the slab. It looks like the slab hung up on the stair, but heaved at the crack location.

Removal of the rock garden/retaining wall is one possibility, but that would entail building a new cheek wall for the landing and stair.

If the rock garden is to be preserved, just ensure that the slab is free to heave as nature dictates, although it's a bit late now as the damage has been done.





BA

 

[DoItRightTheFirstTime]

I just got back from Menards with material to start the job. What I have found out after lots of measuring and inspection is that the rock retaining wall pretty much did it's job over the years and protected the top landing very nicely. The steps however seemed to have pushed down and out a little. I thought the rock wall was sinking and bringing the steps with it but that is not the case. It sounds like you guys nailed the problem pretty good and there isn't much I can do about it but I will build the small wall in front as it will look better and probably will help in the future a little. Thanks again for all your advice!

 

[r13]

BA,

I see your point now. I missed the cracked slab as paving stone tiles It (if true) is absolutely caused by freeze-thaw cycles. A difficult problem to solve, but I don't think the dirt pile and rock have much to do with it. As you correctly point out, the rock been there for years, given it's tremendous weight, the soil below shall have already been consolidated, thus the heave might not have any effect on it.

 

[DoItRightTheFirstTime]

Hello BA,

The slab is shaped just like the photo shows. I had 2 layers of 6 mil poly under the rocks and the rocks in front of the big stone are sitting on the poly so the retaining wall would be like retired 13 drew it. I need a lesson on how you get the photo on the thread to draw on it??

 

[r13]

Take a screen shot, and paste to a graphic editing program, such as adobe photoshop, or the cheapest - "paint" came with window.
I think BA used one of the two of his favorite free programs, so nice line drawn.