What we did with the new thumb, or, trying to be like Squizzy

[digger242j]

The job involved retaining the hillside behind the house. It's new construction, but the lot is pretty steep, from the street all the way to the back of the property. The garage sticks into the hillside fairly far, and if left as it was, the slope would've ended right at the wall. that would've been a big problem as far as drainage goes. The solution, as prescribed by the architect/builder, was to construct a "boulder wall".

There's a perforated pipe, in a gravel bed beneath the whole length of the wall.

The boulders came from a quarry about 50 miles east of Pittsburgh, in the mountains. It took the better part of two triaxle loads. The guy that delivered them was pretty skilled at dumping them. he sort of raised the bed slowly, and as soon as the load started to shift, just let the truck lurch forward, propelled by the rocks coming out the back. They all come at once. (Actually, the guy that loaded them did a pretty nice job too.)

[digger242j]

Once the drain was in place, it was a simple matter of placing rocks, one on top of the other. Actually, it's not simple at all-thet're all different sizes and shapes, so you have to guess at how they'll lay together. Lots of trial and error involved. We filled behind them with gravel as we went up.

[digger242j]

A few shot of the finished product. Personally, I thought it looked a little ragged. It's hard to make a bunch of odd shapes fit together. I thought it could've used a day or two with a hammer and chisel, and a pile of smaller rocks to fill all the gaps, but everybody who matters (like the people who're paying the bills, and didn't want to pay for a day with a hammer and chisel), says it looks good.

[digger242j]

Also, here's one shot from far away, to show exactly how far into the hill the house does sit.

So, how about it Squizzy--can I add "Limestone Wall Builder" to my signature?


:)

[Jeff D.]

One of Squizzy's walls is being shown in "Better Homes and Gardens", so you've a pretty high threshhold to meet.:bouncegri

I certainly know nothing bout building no walls, but I think it "looks" good. In a couple of years nature will have it blended right in nicely.:yup

If he won't let you have "wall builder" you can add "thread hi-jacker" to your signiture if you want, then you'll be somewhat like him.

[Ford LT-9000]

I would have probably dug more of the bank out to move the wall back farther. I do have a feeling you may have to cut a bench above the wall to take some of the load off. Myself I never like building houses that close to banks all it takes is a heavy rain and you can have a mud slide into the house.

The wall looks good otherwise its nice to work with even shaped rock.

[CascadeScaper]

I would have probably dug more of the bank out to move the wall back farther.

I'm taking a stab in the dark, but it looks as if he was staying under a certain height so the wall didn't have to be engineered. Around here, it's 4 feet, is that the same everywhere else? What he could have done is a terrace, but it would have been a much bigger job. All in all, nice work! I did 3 walls this summer, money makers, that's for sure. We usually charge around $15-$18 a square foot depending on rock, etc., pretty good money.

[tylermckee]

Tomorrow ill see if i can grab a few pics of the rock walls a guy in my town builds, talk about skill. I know a year ago he was charging $40+ a square foot, and had work lined up for months.

Looks like nice stone to use for building walls, what we get from our local pit is just boulders of any shape or size, loaded with a loader so you get what you get. You usually have to get atleast 2 loads of rock to do any size wall just so you can pick through and get the ones that fit the best.

Nice looking hillside retention device, i see you used good backfill and thought about drainage. I cringe when i see some of the walls people are building around here. 10' high rock walls 5' away from the house, backfilled with native clay/crap/topsoil/whatever is there. A lot of times you can look at the wall and see where rocks are already being pushed out, and the houses are still in construction!

[nedly05]

:thumbsup Looks really good to me. It's definitely well built, good backfill and drainage. What kind of a thumb is that? It looks like the one we have on our 70SR. Nice job!

[Squizzy246B]

Digger, full marks for execution, well done. I really like dry stacked walls. There is a weird satisfaction in looking at a rock and knowing exactly where its going to fit.

But anyways, since your asking, I'll just have to go ahead and say your designer sucks. I'd give that wall a 50/50 chance of hanging together for 5 years. Basically Ford is on the right track and Cascade has aluded to factors we have no knowledge of ie..budgetry constraints etc.

Rolls Royce would have been a SRW with one pull of Geogrid back into the hill. But if the budget didn't extend then double filter fabric within the aggregate may have helped run the water down to the ag pipe. Another ag pipe about 1 foot higher would be good too. The problem I see is with the wash through in heavy rain...despite all the drainage you have down its probably still going to blow through in a downpour that occurs when the ground is already sodden.

The way around that is to heavily stabilise the backslope with landscape fabric, mulch, trees/shrubs and maybe a small spoon drain....that could work well. I have studied dry stack walls in the UK that have stood for 500 years and more and the back slope is always reduced close to the wall and vegetation is always encouraged.

Sorry to be negative. Nice workmanship...not sure about the design and I'm commenting on geography and climate I absolutley zip about.

Its an interesting subject and one much debated...an SRW puts up a almost impervious barrier that can lead to a build up of water behind the wall if everything is not perfect. A dry stack mass wall will let the water through...It just depends how fast it comes. Filter fabric can clogg up causing problems.....like I said...500 years and more.

If it were up to me I'd go back another couple of feet into the hill, use more mass (thickness) in the rock wall and have some sort of drainage arrangement/plan for the front of the wall if a lot of water comes through. Just to keep the damp away from the building. But then you gotts to do what those designers specifiy don't you?. Thanks for the post. Cheers

[Squizzy246B]

Oh...and to gets your limestone wall ticket you will need to come to the home of limestone wall building and work like a dingo for months. PS...the boss is real A-hole and the pay is lousy when your the new guy.:rolleyes:

[digger242j]

PS...the boss is real A-hole and the pay is lousy when your the new guy.


And once you've been there a while, the pay might get a little better, but that's the only thing that changes... :)

[xkvator]

.


And once you've been there a while, the pay might get a little better, but that's the only thing that changes... :)

.....:roll .....:lmao

[xkvator]

seems to me, that's the wrong house for that lot...

[xkvator]

i collected rocks for a few years out of foundations, land clearing & used them to build a wall next to the driveway for a parking area & extends to the backyard...

[Squizzy246B]

.


And once you've been there a while, the pay might get a little better, but that's the only thing that changes... :)\

No...:nono ..NothingChanges:rolleyes: :D

[digger242j]

The house was designed for that lot. The company has their own architects, and while on some of their developments they work with a handful of standard types, on this site they're designing them individually. It's a tough lot to build on. I should add, that there is a solid retaining wall, about 5' high, at the side of the driveway apron. You can just see the top of it in one of the other shots.

On edit: I added a yellow line to the pic, showing, roughly, what grade was before any work was done.

The pic below shows roughly where the full basement, crawl space, and garage floors are located. It's a poured concrete foundation, which is uncommon in this area. (I understand that concrete block foundations, which are pretty much the standard here, are rare elsewhere.)

Before the wall was built, and the area between the wall and the house graded, there was a serious water problem in the basement, (indicated in blue). The basement does have what should be an adequate drain around the foundation too. There's plenty of groundwater on the site, although that particular lot isn't too bad. The builder said that once the grading was done, the water problem would be cured. I was skeptical, knowing that being at the base of a hill like that, the water could be originating from well below the surface. I was also wrong--it's fine now. :beatsme

As far as the wall itself, there is a drainage swale that runs along the top edge of the lot, so any water reaching the wall itself should theoretically be only that which falls on the slope itself. The dirt behind the wall is virgin. The slope that's there had a pretty good cut taken off it already, and what's there behind the wall is stable shale. I see the wall as more of a device to prevent the face of that from weathering and eroding, than as an actual "retaining" wall.

As far as the weather goes, we build for a 3 foot deep frost line. While a typical winter has plenty of freeze/thaw cycles, I'm thinking that the thickness of the wall from front to back will keep those freezing events reaching behind the wall to the undisturbed dirt, to a minimum.

Nothing special was done to the slope as far as stabilization. It was just hydroseeded.

It's hard to tell from the pictures, but the area in front of the wall does slope away from the house, to the wall, and that in turn slopes toward the camera (in this picture).

[digger242j]

There is a weird satisfaction in looking at a rock and knowing exactly where its going to fit.

Oh harsh critic, I've got one in mind for you...

:bouncegri

[Squizzy246B]

The house was designed for that lot. The company has their own architects, and while on some of their developments they work with a handful of standard types, on this site they're designing them individually. It's a tough lot to build on. I should add, that there is a solid retaining wall, about 5' high, at the side of the driveway apron. You can just see the top of it in one of the other shots.

On edit: I added a yellow line to the pic, showing, roughly, what grade was before any work was done.

.

Ok..Now I'm not worried about the wall...I just want to know whats stopping the house from sliding down the hill:rolleyes: :bouncegri

[digger242j]

Before going any further, I'd be remiss if I failed to mention that Will Gurtner contributed his share to the boulder wall above too. (Be too critical, and we'll both be after you.) :wink2

Ok..Now I'm not worried about the wall...I just want to know whats stopping the house from sliding down the hill:rolleyes: :bouncegri

Funny you should mention that, since I've been working on some pictures of a real "RETAINING" wall, and wondering whether this house is someday going to slide down the hill.

First pic, from Google Earth, from directly overhead, shows the extent of the wall. What you don't see is the slope of the lot--Maximum buildable slope in that municipality is, if I recall correctly, 25%. This lot was said by the engineers to have a slope of 24 1/2%. :rolleyes:

The top six feet or so of soil, beneath the topsoil, is our "Pittsburgh Red Beds"; Red clay, that is slippery when wet, and answers the call of Mother Nature to move downhill.

I dug through this layer when I dug the foundation for the house. At the very back of the house, where the basement floor is at grade, the footer is just below the bottom of the red clay. It follows the slope uphill, and in front of the house, where the retaining wall is, it is just above the grade of the driveway. At the bottom of the red clay, there's a layer of gray, and it's only about an inch thick. The groundwater follows that gray layer, and it's what the geotech guys call a "slip plane". We learned why...

[digger242j]

Second pic is from a lower angle. I've annotated to show an area where we put compacted fill in the driveway. That was the natural watercourse. The driveway is bordered on the high side by a solid retaining wall, about 5' high. It's constructed of concrete filled 12" Ivany block, and faced with brick that matches the house. (Is everyone familiar with Ivany Block, also called H Block?)

At the front of the house, you'll notice a circular area that stands out from the rest of the driveway. It's about 40' in diameter and paved with flagstone. The retaining wall borders it.

The paving contractor brought in a track loader and dug that area. The maximum cut was about 5', but that gray "slip plane" was right at the bottom of the cut. This was done on Friday. On Monday morning, when everyone came back to work, the whole hillside had migrated about 4' toward the house. :Banghead Climbing the hill afterwards, we found cracks that had obviously existed before construction began--they had weeds growing in them. They're at the top edge of the clear area above the wall.

I had to dig the whole slide area away, and install a curtain drain at its upper edge. That was a fabric envelope, filled with gravel, and a perforated pipe at the bottom, going to an existing connection to the neighborhood storm sewer system. The dirt was re-placed, and roller compacted. At its deepest, the curtain drain is about 10'.

(Sorry, resizing the pic makes it hard to read the notation about the slide, but it's in red. The arrow shows the movement.)

[digger242j]

These pics show the footer for the retaining wall. One foot thick, five feet wide, with an 18" key at the center, a foot deep. 5/8' bent rods tied to the rods in the footer stick up into the spaces in the H blocks. (That's what the plywood with the holes cut in it is for--to get the proper spacing.)

The architect/builder, (same guy as the other house/other wall) said the curvature of the wall would be sufficient to make it stand up to the possible push from behind. Once the blocks were filled, the space behind was filled entirely with gravel, and there is a drain pipe directly behind the block.

In the last pic, the skid loader is sitting in the circular area in the GE shots. The block portion of the wall is partly built.

[digger242j]

Last two pictures.

First is of just the footer excavation for the wall running down the length of the driveway.

Second is of the wall, with the face partly finished. They had real stone masons do that part. Hammer and chisel work, cutting to fit, and all of it mortared in place. (I thought I had a picture of the finished work, but I can't find it.)

In the overhead shots, you can see a gap, where there's a sort of ramp up onto the landscaped area above the wall. You can see that in the pic of the partly finished wall.

In the long, relatively straight run down the driveway, there are block returns about every 10 feet, tied into the footer and the face of the wall, with the same rebar detail as everything else. They go back about 4' to the undisturbed bank behind the wall. All the space behind there is gravel filled and drained as well.

This was done in the summer of 2000. Last I knew, it's still standing.

(BTW, this house, by the time the owners finished with the purchase of the land, the building, and all the outside stuff, cost around ten times what the other house is selling for.)

[Steve Frazier]

Holy crap!!

How many yards of concrete are in the footings?? Do you know what the price of this wall was? If it moves, I think we're all in trouble!

[digger242j]

I don't recall, or even know if anyone outside of their office
even totalled it up.

On Google earth, the wall measures about 270 feet long. If I dug it to exactly the right dimensions, which never happens, it'd be 65 yards or so, just in the footer. I'd guess it was more like 75 by the time it was all done.

Taking the average (guesstimated, now 6 years later) height of the wall, at fifty 12" H block per yard of concrete, there's probably another 45 yards of concrete inside the wall too.

In one of the pictures, you can see the 8" blocks in front of the 12" blocks. The stone face is laid on top of a couple courses of those, but there's an awful lot of square feet of stone laid there.

[Squizzy246B]

Sufferin Suckertash...:eek: there's a whole lot of $$$ gone into the side of that hill. We humans tend to think geometrically and go for "solid". Why don't we just put the house on some skids and let it slide....."let it slide"...sounds like a line from one of Jeff's songs....or was that the Country Bears??..anyway...I digress....I'd have gone for pole construction:rolleyes:

I think I'm glad I live in the land of sand. We just finished a job up in them thar hills and with a bit of luck I wont see clay for another 6 months.

Thats some nice work with the wall. I'm trying to get people here to lets us do the retaining work with concrete tilt panels and then clad it with stone but they all seem to want what we have been doing here for the last 200 years and thats solid limestone mass wall. Oh well it pays the bills.

Thanks for posting that project Dig...whens the next lot coming..??? :D

[digger242j]

Thanks for posting that project Dig...whens the next lot coming..???


Here's one I did in China a few years ago. It was one of those Friday jobs. :rolleyes: It ended up crooked and it's not quite level. Good thing your guys didn't do it while you were on holiday--you'd have ended up redoing it... :wink2

[digger242j]

Per Forum policy--the above image was pirated from: http://images.google.com/imgres?imgurl=http://www.bergoiata.org/fe/grande-muraille/Great%2520Wall%2520of%2520China,%2520Beijing.jpg&imgrefurl=http://learnaboutchina.tripod.com/&h=768&w=1024&sz=141&hl=en&start=11&tbnid=eO5CV-1FFivC1M:&tbnh=113&tbnw=150&prev=/images%3Fq%3Dgreat%2Bwall%2Bof%2Bchina%26svnum%3D1 0%26hl%3Den%26lr%3D%26sa%3DG

I don't know why they were out taking pictures of my work. :confused:

[Squizzy246B]

Here's one I did in China a few years ago. It was one of those Friday jobs. :rolleyes: It ended up crooked and it's not quite level. Good thing your guys didn't do it while you were on holiday--you'd have ended up redoing it... :wink2

Naww...that wall will never hold up...I reckon another 2 maybe 3 hundred years and it'll come down:rolleyes: :Banghead

And stop hi-jacking your own thread...thats a job for us pros:bouncegri

[Countryboy]

:lmao

[will_gurt]

Holy crap!!

How many yards of concrete are in the footings?? Do you know what the price of this wall was? If it moves, I think we're all in trouble!

I can not remember how much crete was in the wall footer. The house footer has over 90 yards in it though.

[xkvator]

Also, here's one shot from far away, to show exactly how far into the hill the house does sit.

if i was spending the kind of money that house probably cost...i want a back yard...JMO

[digger242j]

I'm not sure which of the houses you're talking about, not that it matters. Neither of them has what you could consider much of a yard, front or back. And for this builder, that's not at all unusual. They've made townhouses their bread and butter for close to 30 years, and even their single family detached houses don't usually have much yard to speak of.

BTW, I agree with you...

[tylermckee]

They dont build houses with yards around here any more. Nearly every house we build we design it for the lot, and the house will be sitting on every property line setback :rolleyes: usually something like 20' front and back and 5' on each side. And if we arent stuffing a huge house on a small lot, we are trying to shoehorn it in between the trees for the homeowner. We seriously had one homeoner trying to get us to leave a 36" diameter fir tree that was about 2 feet away from the foundation, and already leaning towards where the house should be, the tree would have went through the second story. its a 3 million dollar house sitting ontop a cliff right above the ocean, probably sitting back about 20-30' from the edge of the cliff. we had to redo the existing driveway to get to the lot because it was running at 25% :eek: