Building a concrete wall question

I want to build a concrete wall that is 56.5 ft long and 4 ft high from the top of the wall to the bottom of the trench, that is, total height including the footing. The wall will be 10 in wide and the footing will be 20 in wide by 8 in. (or 10) deep. It will take 7.5 yards for both the wall and footing. The footing alone will take about 2 yards. If they bring 7 yards will be chipper that if I order 2 plus 5. Then, I would have to pour footing and wall at the same time. Would the concrete stay in the forms up to a height of 4 ft? Or would if flow out through the bottom? Also, since the wall slopes by 3.5 ft over 56 ft, will the concrete run to the lower side?
Than you
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
A 10" thick wall seems a little heavy but I assume you have your reasons. Pour the footing the day before forming the wall and I would use (hire or rent) metal forms with regular form ties. That would not only be easier, but cheaper than all the form lumber it would take. Put the footing deep enough to allow you to use 4 foot forms and of course pour them full to screed off the top. I would use 24" wide footings. If this is a retaining wall and it sounds like it could be, I would go with at least 36 inch wide footings. With your questions, I can see a disaster if you don't use this method. Three feet of fall in 56 feet will be manageable though I would use a slight slump, ie fairly dry. I assume you plan on using steel rebar too.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Works out to .75" per foot fall/rise. That's steep enough for guaranteed drainage leaving solids behind the wake.
Consider stairstepping every 10'. Depending on the soil content and how deep you go, the footing may walk.
Pour the footing first. Leaving some rebar exposed to tie it to the wall above it.
--
Jonny



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Alpha One wrote:

Learn a bit about concrete; then re-plan the job. You seem to be planning a retaining wall to retain a sloping grade, probably on the side of a residential lot. The first step is to accurately survey the site. Determine where you want the wall. If you want it on your side of the property line, determine where the line is. Then using a water level, figure out exactly how much difference there is in height from one end of the line to the other. Then, find out how low frost footings are supposed to be in your area. --- That's enough for now. Report back.
--
(||) Nehmo (||)


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

the
including
wide
I'd have to believe your footers are undersized. Dan

will
2
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Right off the bat I can assure you your wall will certianly fail with those measurments. What is the reason for this wall? Why 10" thick? We recently did a basement in the Bay Area for a historic 3 story house and the walls were 10" thick. I believe if you are not married to concrete use block and step it down as suggested. The money you will save in materials and labor vs forms (even renting) will be worth it. If you are a do it yourselfer there are several different block styles that would allow you to lay them yourself relativily easily. If you dont want the "block" look simply put a skim coat of stucco over the block. Compared to 10" thick concrete using 6" or 8 " block will leave you with money left over. Dan Deckert wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I agree with others; you haven't said what the wall's purpose is or what the conditions are on the site.
If this is a retaining wall, it is low enough to not be too hard to do if you get enough footing under it. I also agree yours sounds undersized and your wall thickness sounds like too much.
If it's a retaining wall, what type of soil will it hold? Is it expansive, like clay, when it's wet?
Is there any chance that you will have water build up (pressure) behind it? If so, have you planned for drainage?
How much dirt is behind the wall in the sense of slope? Is there a steep slope rising behind it, or is it level ground?
Will there be any unusual loads placed above the wall, such as a road or driveway or a nearby swimming pool above it?
Does your climate present a frost heavy issue?
In our area, walls that are 4' or less don't require an engineer, but that doesn't mean they aren't a good investment especially if you don't know too much yourself. We don't have deep frosts, so engineering for that isn't an issue. You can google retaining wall and retaining wall drainage and learn a lot really quick.
Now, if this is just a decorative wall for a screen of some sort, everything changes except for my $.02 your footing and wall thicknesses still seem out of whack.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The wall will be a retaining wall in my backyard. I intend to use three 3/4 in. rebars orizontaly and vertical ones spaced 2 ft or so apart, plus two 3/4 in. rebars in the footing. Nothing will be on the top of the wall. The soil underneath on one side is rock for a distance of about 25 ft at a dept of about .75 to 1 ft, and the other 31 ft is soil never moved. The footing will be 24 in. wide, maybe more, by 12 in. deep. The dirt behind the wall is dry and will be about 5 in. below the top od the wall and it goes flat from there. There is no drive way or anything else on it, just grass. I intend to use gravel and a pipe plus cloth for drainage. The wall's hight over the rocky side will be about 3.5 ft. (from the rock to the top of the wall). The rest of the wall, starting right after the rock will be 4.5 ft. from the bottom of the footing to the top of the wall and at the other end will be 3 ft, also from the bottom of the footing to the top of the wall.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Alpha One wrote:

Your design is "somewhat" close but IMO #6 bars are way too big & the distribution needs a little work. Footing needs to be wider & needs to have some distributed rebar in it.
checkout
http://www.fairfaxcounty.gov/dpwes/publications/retainingwall/sheet07.pdf http://www.sonoma-county.org/prmd/docs/handouts/bpc-016.pdf
& adjust your design accordingly
cheers Bob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Just for fun humor me and check out the price of block verses what you are contemplating. There are alot of things yo may not have thought about. Renting forms: by the time you go get them oil them down buy all the "additional" ties take them down CLEAN them stack them you can have the wall built of block and when its done its done. Of course you would have to "grout" the wall (fill it with concrete) also but trust me you would still be ahead..ever seen a concrete form blow out?........ hey I have nothing against formed concrete walls but there is a time and place and I think if your thinking of money savings (arnt we all)..well you will see give it a try Alpha One wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Three years ago I built a concrete retaining wall in the same backyard 10" wide, 5.5 ft high and about 44' long. Plus the footing which was 3' wide by 1.5' high. When I was finished I had spent $2,500.00 or more. This included concrete, steel, wood for the case, etc. If I had done it with blocks it would be much cheaper, but also less strong. Because it is in a L shape one side keeps the other from tipping. On each end the dirt goes up to the top on the outside also. So, it should stay in place for quite some time.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
That's low, even for just the materials. And do you mean forms by the word "case"? -- (||) Nehmo (||) -------------------------------------------------------------
Alpha One wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
More accurately:
Today I measure the wall and checked the receipts. The wall is 51' long. 34' has a footing of 3' by 1.5' and a wall of 10" by 5.5'. On one side 17' are only almost 2' high by 10" and no footing; it sits on top of a wall previously there. I ordered a total of 12.5 yards at $75.00 was $993.75. With rebars, wood for forms (case) etc. I spent $2,784.00. This is for all the materials including any tool I had to purchase because of the wall.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
How did you dig the hole? And how did you make the forms? You made forms 5.5 feet high? I'm not saying you didn't do it, but that's something of an accomplishment for one guy and $3K. You didn't mention paying any labor, so I assume you did the whole thing by yourself.
-- (||) Nehmo (||) ----------------------------------------------------------------- Alpha One wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
By pick and shovel. Took a while and lots of dirt moved. From begining to end it was just myself. The forms I did with 2x4s and 3/4 plywood. I tried to send a picture as an attachment but it didn't go though. If you go to alt.binaries.photos and look for 'For Nehmo' you can see the wall form different angles.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Use http://www.imageshack.us/ or http://www.flickr.com/ or http://www.imagehosting.us/index.php or if you want a ng, news:alt.binaries.photography . My newsserver doesn't carry the ng you used. The photo hosting sites will hold the pics much longer, but there's a size limit. -- (||) Nehmo (||) ----------------------------------------------
Alpha One wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.