Retaining wall layout on corners of house (pics)

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Old 04-13-11, 05:15 PM
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Retaining wall layout on corners of house (pics)

Hi Folks,

In the below pictures you can see two ailing retaining walls on both rear corners of my house. I'm looking for suggestions on how to lay out the wall so that it blends well with the existing grade. I like the idea of stepped planters (well, the better half does more-so), so even if I curve the wall inward, and place one or two steps, this could suffice.

Some specific questions - we'll assume using a segmented retaining wall system (Pavestone is the local manufacture).

1-As you can see the existing timbers by the heating unit have been pushed away from the corner of the house. Is it recommended to tie the retaining wall into the foundation/block some how?

2-Both corners have drain spots right there - would it be wise to just go ahead and lay a gravel bed, weeping tile, and tie in?

3-If I do a concave wall with convext stepped planters, do these get tied into the main wall somehow?

4-Lastly, I would like to someday add a small deck in the large gravel area - if I'm using sonitubes or similar as support, do I really need to take this into account when designing the retaining wall? Nearest support would likely be 6+ ft away.

Thanks in advance, much appreciated!
Jamie and Melissa.

One corner:


The other:





 
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  #2  
Old 04-13-11, 06:58 PM
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Not 100% percent what your trying to do but i do have a few tips.
Landscape timbers are not even below ground rated. It should have been at least 4 X 4's or better yet 6 X 6's rebared in place.
There was no drain system installed behind that wall to reduce pressure.
There really needs to be gutters.
There was no dead men installed to hold the retaining wall in place.
 
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Old 04-13-11, 07:09 PM
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Some comments -

1. If you use a segmental retaining walls system (SRW), it is a flexible system that should not EVER be tied into a rigid home foundation. If properly built, it will be stable and resist Mother Nature.

2. Gutters and weeping "drain tile" serve different purposes. You need a solid wall drainage pipe to carry the water away from a gutter drainage system. The perforated tile allow collection, but can also allow a sudden downpour to flood the soil around the house. After you get away from the house, a solid wall is the best to use to carry water away. Do not EVER connect the two drainage systems if you want to avoid back-ups. Rainfall is an immediate drainage of high intensity and a buried tile system is a steady and slower proven method of reducing moisture in the soil.

3. Convex and concave SRW walls can the lapped together depending on the space you have available.

4. The segmental walls will be separate from the deck supports (Sonotubes), which can be located within reason to carry the concentrated vertical loads and are not really affected by the lateral load from the SRW wall.

Dick
 
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Old 04-13-11, 07:44 PM
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Thanks to both for your input.

Joe - I think I'll apply this approach (using 4x4 or 6x6's) to the smaller wall. Seems better suited here.

Dick - So you're saying that if I tie the SRW's drain into the gutter discharge, it could potentially back flow *into* the SRW's weeping tile. Makes sense. I'm going to have to think about where to direct this water now...

I've attached a few quick drawings - please excuse their simplicity. Hopefully you can better understand what I'm trying to do with the curvature (nevermind the convex shape mentioned earlier). You can see I'm trying to mimick the PT timber layout.

I presume all SRW's are interlocking, so how do you go about interlocking the blocks where they meet at the corner of the house? You'd almost have to knock the key *off* to allow them to lay flat (as they would be off-angle).

Would you recommended any type of membrane or drainage matt against the backside of the block, or is this overkill? Otherwise do you see any pitfalls? I imagine the block manufacture would be helpful in final details as well.

Thanks again,
Jamie

Top/aerial view:


Side (I've only drawn the top row of block for each 'step'. Each row below the first would become increasingly narrower, offset more and more to the right to contour the grade.


Drainage (the steps are drawn closer together than I would intend them to):
 

Last edited by slipnfall; 04-13-11 at 08:18 PM.
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Old 04-13-11, 08:07 PM
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Not all walls interlock. You have to make sure you get the right style for your project. I suppose they can interlock differently as well. The block I used for my retaining wall uses plastic pins. The design allowed the block to be stacked with all the faces flush or to step back each row 1".

What's that wall near the basement door made from?
 
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Old 04-14-11, 07:37 AM
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drooplug -

Those were probably the original Versalok block. The good pins are really pricey. I think the newer versions do not use pins.

Jamie -

Sorry I miss-read the "weeping tile" and erroneously got into thinking about drain tile used for basement waterproofing. What you are proposing should be adequate, but a good "gully-washer" of a storm could add some moisture up into the area behind the walls, but there will also be short term water fro the rain at the same time. It can be a big problem with drain tile for waterproofing a basement since they are much deeper.

Regarding the butting up to the house, many (most?) of the blocks have the back side made shorter (1" - 2") than the face, so they can also be used for outside corners. If the block has "ears" on the end, you can knock the off the ones on the back side with a hammer. If you look at the web sites for the leading developers of the SRW systems (Allan Block, Anchor Wall Systems, Keystone and Versalok), you can find many design ideas and installation instructions. If you are faced with copied system, there are certain features that may be eliminated to get around the patents.

I suspect drooplug was rightly concerned about the soil grade being high enough to cause the soil to be in contact with a wood framed wall with just a veneer. - A code no-no.

Dick
 
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Old 04-14-11, 08:33 AM
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I've been using the Keystone Compac retaining wall blocks for over 8 years now. They use the fiberglass pins to lock the blocks together top to bottom as drooplug mentioned. I bought some two weeks ago and the pins are less than .50 each and the blocks were about $5.50 each for the 77lb 18" wide x 8" high ones. I can't recall the price for the cap stones I think they are about $3.50+ each and weigh 45lbs. These are prices for me picking up at their yard. If you have them delivered I am sure the price would be higher or have a delivery fee.

If you spend the time to do a good level foundation and make sure the first row's blocks are level the rest of the wall goes incredibly fast. You just have to prepare your back for hefting those heavy blocks. Good gloves are a must and steel toed shoes are a good idea in case a block slips out of your hands. When meeting a house foundation I butt up to and touch the foundation but do not attach to the house or foundation.
 
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Old 04-14-11, 11:12 AM
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The original big "dog bone shaped" Keystones are definitely back breakers. The original ones were about 90#.

The price of $0.50 per pin is lower than what the manufacturers/dealers were paying for good pins (not plastic) a few years ago.

When building a tiered wall, it is common to not have the highest tier of the wall go all the way down to the level of the the lowest wall, but that is for walls that are much higher and have more distance between the individual walls. I have seen walls that were 40' high with a 20' high wall above that, but it was engineered and the 20' higher wall was about 20' back from the lower 45' wall.

slipnfall -
You could build a wall like you propose with the smaller (or lighter ) units than the back-breakers. There are many of the 16" long by 12" deep interlocking units with rear "shear lugs" (lips) that are lighter and work just as well for the limited loads you have. The caps are usually attached using dabs of silicone adhesive to allow the wall to move and flex. - It is a flexible wall by definition.

Dick
 
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Old 04-14-11, 01:08 PM
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The block I used was made by EPHenry and used plastic pins. I bought and installed the block last fall. There might be a height restriction for the block I used.
 
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Old 04-14-11, 01:54 PM
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drooplug -

If the block were made by EPHenry, they are probably one of the 4 leading systems and I would be surprised they were selling a "knock-off".

Usually, the height restriction for all gravity walls is a local code restriction and is either 4' or 5' high and does not depend on which brand is used as long as it is installed correctly. Beyond that height, engineering may be required for obvious reasons. Around here, the municipalities, counties, etc. all have standard design/construction/inspection plates for their employees to use for installing retaining walls for street widening, new sidewalks, erosion control, etc. and they strangely look similar no matter which major brand the municipal organization buys or specifies.

Dick
 
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Old 04-15-11, 08:32 PM
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droop - the entire basement is 8" block on the front/sides with brick fascia, and I suspect either 8 or 10" around the back side where the basement is completely below grade. The angle of that picture may be deceiving, but the gravel around the corner is a good 5-6" away from the top of the block wall.

I'm going to shop around more tomorrow, but the only thing available from HD/Lowes is the solid 4"H block (8/10/12"W) with a solid 1/2" or so lip on the back/bottom. Doesn't seem very conducive to curvature without the block setting back more than normal from the row below. Hopefully some of the local building supply places have a better selection.
 
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Old 04-15-11, 09:36 PM
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I'll likely be working with the smaller blocks, simply because it's a confined space and would likely be more aesthetically proper. In reading the manufacture spec's on some of the blocks, it looks like they are only rated for 2 and 4' height (depending on model).

That said, I think what I'm trying to do here is a bit outside the scope of the SRW's intended purpose... do you think the below could fly? I would end up partially burring the 'ends' to contour with the ground.

Again unsure how the ends near the corner of the house would stay tied together, if it would work at all. I certainly don't want to go through this all only to have it fall apart a few years from now.



Thanks again,
Jamie
 
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Old 04-16-11, 05:54 AM
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If you are using the blocks that have the lip hanging down on the bottom then I don't think you can create the vertical stack needed for the corner.
 
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