We’re having a 20 X 30 ft. Slab on Grade foundation put in next week … to handle a house addition that is separated by three feet from the original house. On two adjoining sides of the new addition we can have no openings of any kind — windows or doors — since we’re taking it right up to the property line… no setbacks. (yes .. it’s all permitted and totally legal)
So … we’re thinking of building our own cement block walls along those two sides — they would join at one corner. I’ve built this and that on and off over the years — an addition to another house .. conversion of a garage into an apt. .. etc. But I’ve never worked with concrete block before (other than bookshelves!)
We’re wondering if there might be some general concensus here on whether or not it would be a good opportunity to use icf’s or some other approach we may not have heard of. Or if someone here with experience may be able to steer us towards (or away from) some resource or other involving building with cement block that might have been helpful to them.
This will be two walls, both 10 ft. high … one 28 ft. long .. the other 19 ft. .. intersecting at a corner.
Thanks!
Terry
Replies
Research first! And practice. And think long and hard about whether you really want to do this yourself with no masonry experience.
Masonry is hard heavy work that doesn't wait for you to figure things out. The mortar gets hard while you scratch your head. If you have never watched masons work, you should. Say what you want about them, but they are truly craftsmen and I have the utmost respect for them.
I've done a few little projects the involve no more than one sack of mortar, but I would never think of doing a wall like that.
If you haven't drawn blood today, you haven't done anything.
So, the block walls on only a slab on grade has been approved by the building inspector?
If you haven't drawn blood today, you haven't done anything.
So, the block walls on only a slab on grade has been approved by the building inspector?
It's a slab on grade in the middle of a perimeter -- which will bear the walls -- with footings that are 16' W x 10" D. with 8" stem walls... all on dry, level ground. Are you of the opinion that this will somehow likely 'fail'? Not arguing ... asking sincerely.
I tend to go ahead and do things -- very, very, very carefully -- that, quite possibly and quite often, I "shouldn't". It's awfully slow .. painstaking even .. but so far so good. Of COURSE after I'm done with my first time in any given arena I then know 'how I woulda done it differently' ... but I have found that with all of the visual aids and books and resources available today -- this very forum being one of them, and a fine one indeed -- many things are 'doable' that my father would never have considered NOT hiring a 'professional' for. I DO have that natural, physical 'knack' for physical/mechanistic undertakings which I'm sure many here do. I trust it implicitely and do a lot of research before beginning. And I'll bet that a basic, ninety degree wall can be built -- with the resources available today -- by a careful, thoughtful man who has never built one before, that will, with a little luck perhaps, end up being, straight, plumb, and solid.
I know not everyone will see this as sane. But if I'd listened, I would never have had as much fun as I have.
Terry
a few questions:
are you excavating for footings, pouring footings, then laying 8" block stemwalls on top of the footings to grade, then pouring your slab on grade and on top of the stemwalls, and then laying your 10' high walls on top of the slab ?
carpenter in transition
are you excavating for footings, pouring footings, then laying 8" block stemwalls on top of the footings to grade, then pouring your slab on grade and on top of the stemwalls, and then laying your 10' high walls on top of the slab ?
I'm having the foundation .. oversized .. excavated and poured over the next 8 or 10 days ... they start tomorrow morning. This will be completed with the slab pour. Hopefully this will result in a flat, level surface ... underneath which will be footings 16" W x 10" H. .... with 8" walls to the slab surface. This is, again, what the walls will be built on.
For this interest and other recent contributions to the thread ... thanks !
Terry
I'm having the foundation .. oversized
what does "oversized" mean ?
why have you chosen to pour the slab on top of the stemwalls and then lay the block on top of the slab rather than building your walls to their finished height (10' or whatever) and pouring the slab against the walls ?
where is the elevation of the finished slab in relation to the finished grade on the outside of the building ?
can you post a photo of the site ?
carpenter in transition
"oversized" simply means that the footings are larger than usual. 16"wide by 10" deep. (being excavated about 10 ft away from me as I write this). Stem walls are 8". The original plan was for a perimeter foundation with a smalll crawlspace under first floor. Then ... after permitting .. we decided to go slab on grade. So ... we're doing the perimeter then pouring in the slab .. all to the same level .. Then .. we were simply going to do conventional 'stick' walls .. then .. realizing that we'd be so close to the fencces that we'd have no access once everything was up we began discussing long-term maintenance-free materials .. then the idea of cement walls emerged. At first, we spoke with the foundation guys about the walls .. but the poured walls sounded too expensive .. so . block. The finished slab will be approx 10" off of grade.
I don't have means of posting a pic right now ... but should have soon. Why? Are you seeing problems ? ? ?
Terry
The finished slab will be approx 10" off of grade.
above or below grade ?
i am hoping above grade because of water issues.
pouring the slab on top of the stem walls around here is pretty unusual. it creates the need to form all of that slab edge which costs money. then you have that ugly slab edge in between the block coursing. how were you going to finish that off ? any problems with the slab down the road which made slab removal necessary would be nightmarish.
take a look at the first drawing shown on this website. it shows a common stem wall design. this particular drawing is showing the use of Tech Block which is a styrofoam / concrete type wall. i'm not pitching this, it just happened that their drawing showed a typical setup. this drawing would also apply to your concrete block wall.
http://www.techblock.com/manual2.html
by the way 16"x 10" isn't an oversized or especially large footer. i'm sure you've had this specified by an engineer, yes ?
because our excavator commonly uses a 24" bucket, our footers generally aren't ever smaller than 24".
carpenter in transition
Edited 9/7/2005 6:06 pm ET by timkline
Tim,
It's 10 or so inches above grade ... seems to me that it ends up being extemely similar to a standard monopour slab ... The idea is footings and stems ... then prep central 'field' and pour up to top of stem walls. This allows a vapor barrier between slab and stem walls. And a flat surface straight across slab and top of walls. Really no 'walls' ... all one level. (perhaps i'm failing in my descriptive communication here).
The footings are oversized a bit for around here as far as I've heard. Mostly here it's 12" by 8" (or so I'm told). I've had it specified by an architect ... and ok'd 'downtown' by the group of engineers that run the show here.
Right now our back yard is an enormous series of dirt piles and trenches ... half way through the excavation. I'm nervous about them setting the forms tomorrow and then having it sit through a rainy weekend. Wonder if there's a danger in then pouring on MUD!
That Tech-Block method really makes it look like fun! Next time!!!
thanks -
Terry
Terry,
If I am reading this thread correctly, you designed/engineered and were permitted for stick-framed walls, and now you are looking at various masonry solutions. In earthquake country, no less. If my understanding is correct then ya gotta start over.
There is a very good possibility that a footer deisgned for stick is not going to cut it for 10' tall masonry/concrete of any sort (block, ICF, etc). The city will also have very specific requirements for reinforcement (vertical and horizontal spacing, size of rebar, etc.) that you better be crystal clear on before starting.
The parged idea sounds great - hopefuly your footer will take the load of the masonry (sounds like it's too late to change anything) AND your city is up on alternative approaches like parging.
Good luck, and keep us posted!
Wayne
Wayne,
Thanks for the words of caution/wisdom. It is true that the original design was for stick frame. But also, this is a very unusual project, and, as such, was 'overengineered' for weight and sheer factors. Since the walls I'm refering to are only two walls on the ground flr only ... I'm feeling relatively ok about it. But you're absolutely right ... it would be a nightmare to proceed .. only to have the inspector demand that I 'unbuild' a wall or two! I'll proceed with input and with caution.
The fact is .. that for insulation purposes if nothing else .. I have to build the stick walls just inside of and up against these 'parged' walls (if we decide on parging) anyway. In other words ... I'm not 'neglecting' the stick walls ... just sort of using these cement walls as 'outer walls' for the sake of strength and no maintenance. I could even use thinner, say 4 inch, blocks ... parge the outside ... and leave the inside side of the walls clear and flat to build up against since, as stated, the same wood walls with R-21 will be going up against them on the inside. I am seeking extra stength and no maintenance ... and since on these two walls there can be no openings whatsoever .. blocks seem sort of a cheap natural way to go.
As you can see ... we're still considering all possibilities!
thanks again --
Terry
Terry,
I think you may be in way over your head, here.....you can't willy-nilly change a stick build to block...and I have to admit to being very curious as to how you managed to get permitted to build right to the lot line, & wonder just how your neighbors are going to feel...
Just my own 2 cents here, but I'd explore sticking to the original design, and dealing with your neighbors to take down the fence panels, put on your exterior finish, & rehang the fence....
thanks jrnbj --
I'll take your concerns to heart. And .. eventually .. I'll post pics of the 'aftermath' !
You mention my neighbor's feelings. I think they will be less than glowing when they finally put it together what exactly I am up to... but what are ya gonna do. Ya can't go around the neighborhood asking 'permission' every time you wanna build something that not everyone may agree on! Thank goodness I actually have a permit in hand this time! ... especially since he is a City Councel 'elected official'!
Obviously, this is all still 'being grown' as it moves along. Lots of considerations and many changes to come, I'm sure. Myarchitect told me that it's almost become 'rare' to end up seeing a project completed as he had originally gotten permitted ... changes changed changes along the way.
Thanks again -
Terrry
Edited 9/12/2005 1:00 pm ET by newbuilder
hate to burst your bubble - but why are doing something that will probably tick off your neighbors and thinking having a permit will make everything okay - and about that asking everyone if they like "it" - most places have a requirement to get either permission from the abutters (aka guy next door) and other interested parties, usually everyone in a certain (say 200ft radius) -finally, you run a very real risk of having the AHJ (authority having jurisdiction - ie. building inspector, mechanical inspector, etc.) not sign off and possibly having to tear it down - two houses at the end of my street were constructed too close to a wetlands - the further one was allowed to be completed, the other, already framed and sheathed (walls and roof) got taken downif what you're doing is okay under the codes - then you should be okay..... but since you said something about having a permit "this time", you're changing what you were permitted for, and you're not concerned with your neighbors, you don't seem to have too much concern or respect for the codes and laws. sounds like you're asking for problems
There's no requirement here in Seattle to "get permission from abutters" before building. And the inspectors, I expect, will be fine with the job as it has gone through a quite rigorous screening process downtown with Dept. of Planning and Development. As of today .. the footings for this project are in .. tomorrow .. the stemwalls .. two days later .. the slab. Then ... up she goes.
The project was a hard one to get permitted because of its highly unusual nature. But once it is -- or ... 'was' -- there's no stopping it legally. It couldn't have been permitted if it wasn't all totally to code. It is true that I have 'pirated a few things in' over the years ... but only when I knew exactly what I was doing (or learned as I went, as least) AND did everything to code despite no permit. My personal policy has always been, if I'm doing something outside of a permit I MUST do it to code AND record the process step by step with photos. That way, if there's ever a question, I can show exactly what I did. I've sold houses that I've owned in which I've done unpermitted work. I was simply honest about it .. informing the buyers that this and/or that work was performed by me without permitting ... take it or leave it... but no secrets or deception of any kind.
I do have respect for the codes and .. to the extent that they are sensible and truly helpful to us all ... the laws. But you're right about one thing (and one thing only): I don't really care much if my neighbors don't like what I'm building. I've had to look at their building ... one of the ugliest apt. buildings in town ... for years .. and our house has been filled, nightly, with the unecessarily bright lights from their property. They own many many properties around town, they don't live next door .. they only rent out apts there ... and the wife is impossibly obnoxious to deal with when she does come around. She sees herself as the "money'd class" .. so she attempts to call ALL the shots. So ... evil evil me ... I'm actually NOT bothered at all to be legally permitted to build something that I'm very excited about and have been drawing and dreaming and talking about for 8 or 9 years ... even though I feel pretty certain they won't be terribly excited about it! No worries -- no bubble-burst here.
Best regards,
Terry
pouring the slab on top of the stem walls around here is pretty unusual. it creates the need to form all of that slab edge which costs money. then you have that ugly slab edge in between the block coursing. how were you going to finish that off ? any problems with the slab down the road which made slab removal necessary would be nightmarish.everybody does it, that way around here. If you use stemwall header block, there is not no forming and on the outside you cannot tell where the slab is.
Maybe I haven't been clear; It's not that the slab is poured ON TOP OF the stem walls ... it's that the perimeter foundation is totally put in place .. footings and stem walls ... then the soil in the middle is compacted and all of that is taken care of .. vb and insulation, etc .. and the slab is then poured in the middle USING THE STEM WALLS as 'containers. There is a 'felt' liner placed around the inside of the walls so that an expansion joint is formed around the slab edges BETWEEN the outer edge of the slab and the inside of the stem walls. The slab is poured as an 'island' within the boudaries of the perimeter ... with a very small 'joint' running all around it and exactly to the height of the wall. Is this so completely unusual?
Terry
he what I was talking about. picture not good but you can see what a stem wall header block is.
yeah .... that looks a bit like it.
The stem walls will be in tomorrow .. then .. compact soil and all .. pour slab 'against' stem-walls .. same heighth. With expansion joint around perimeter ... slab and walls are separate .. but equal. :]
Hire someone...
Hire someone...
Naaahhhh ... can't afford to!
Gotta do it myself!
So ... back to the original question ... anyone have any good suggestions for "educational resources" for a profect like this?
Terry
I wanna see pics after this one!!
LOL! Have fun with it!I cut the board twice and its still too short ! ! !
I wanna see pics after this one!! LOL! Have fun with it!
I cut the board twice and its still too short ! ! !
I have every intention of posting pics of this project!
You wouldn't believe it if I told you what it was. Naysayers like you give me GREAT encouragement. THANK YOU!!! :)
Sorry about your short board.
I measured mine twice ... cut it once, carefully .. and it's ab-so-LUTE-ly PERFECT!
Terry
By the way ... if there IS, again, anyone who has actual suggestions for resources or encouragement on this project ... love to hear it.
thanks!
Terry
Terry,
Try Taunton's book on Foundations and Masonary. If you are meticulous, but not too meticulous and you have general building knowledge you'll manage just fine. It's like anything, there are a system of rules to fallow. Work in small batches at first. You'll be flying after a couple of rows. I laid a couple of foundations once. Later on I found it better to barter my abilities for those of a mason. It is pretty tough work.
Get the book Wolverine mentioned. With practice it can be done.
A couple of cautions: make sure your foundation wall is dead level or adjust for it in your first course, laty your leads (corners and ends) first, keep your twig lines really, really tight, check you plumb more often than you think you should, rent scaffolding, mud pans and a mixer, get the right sand, keep the sand dry, work fast in small batches, and finally, don't be afraid to take part or all of it back down.
A wall that tall should also have vertical and horizontal reinforcing in it. Verticals at 2"oc and horizontals at 16"(every other course). Have your local code inforcement authority approve your reinforcement design before starting.
More questions?
Bring them back here. We have some really good and smart people that will help.
Dave
Hey hey hey! ...
Thanks to everyone who responded!
Just had my final meeting with the slab on grade guy. Excavation on Tuesday. I'm excited and nervous as hell about it. Spent the day downtown getting permits for BIG TRUCKS around for the next week or two.
The walls are still theory ... open to 'adjustment'. But I'd like to do 'em. Someone mentioned 'rastra' walls as well ... http://rastra.net/rastracom/web-site/wi_ra.htm First hurdle to get over is the foundation. This will be the first totally legal (permitted) work I've ever done. Everything up to here has been 'pirated in'.
Thanks for the support!
Terry
Sounds like you have your head on straight. I understand wanting to do it your self, but there are some things that I won't do. Some because they are unpleasant and some because I don't have time and some because I don't have the skill. I could learn the skill, but I might not want to or it might take to much time or money to learn. Then there are the tools.
I still think you're nuts, but I wish you luck. May the satisfaction of having done it your self override the thought that you wish you had hired someone instead.If you haven't drawn blood today, you haven't done anything.
No one has mentioned this yet, and I'm pretty certain you'll find it in the Taunton masonry book, but here goes. CMUs can be dry stacked and parged with surface bonding cement to build a wall stronger than the traditional mortar method. You have to mortar the first course perfectly level, then dry stack the rest (it goes very fast) You then parge the walls (both sides) with the mix, which has chopped fiberglass to hold the block together. I'd build 5', parge, wait a day, then finish, so nothing gets topply (word?) Shim with brick ties when necessary to level.
I'd look into 10" or 12" block for a wall this tall. My local Home Depot sells the Quikrete version of surface bonding cement - ~$12 a bag
Unless you need the insulation value, you'll be wasting more $ on ICFs than it would take to hire a mason at ~$3 a block.
Some thoughts in reply to several posts:
I GREATLY appreciate all the feedback. And no, I wasn't "just looking for words of encouragement" .. I was, as my op stated, looking for any suggestions towards possibly fruitfull directions in acquainting myself with the process. But hey .. 'words of encouragement' (or discouragement) are always good for pondering.
I LOVE the idea of the 'stacked and parged' wall, of course. ESPECIALLY since you mention "goes up fast" and "is stronger". HOWEVER! My neighbors are not exactly thrilled that we're building right up to the line ... so BOTH neighbors ... to the E and to the N .. are unlikely to let us work to finish the outside from their yards. ((perhaps we could finish it in stages DOWN from the top? what exactly is involved in 'parging'? MUST one 'spray' from a distance? ... or could one 'paint' it on???)) This is ONE of the reason's that we're thinking of going cement instead of wood ... because it would pretty much PERMANENTLY deal us out of the maintenance game. So .. what ever method we end up doing we can't really really on access to the outside surface.
But if a skilled mason really only charges ~ 3/brick ... well then that may be the answer right there! The crew that is doing my slab next week had offered to do a little three foot wall along the long side to get us up out of the 'crack between the walls' so as to insure future non-rot down low between our wall and their fence where we won't be able to get at the wall once its up. But they wanted ~ $2000 for it and I figured I could do it for SO much less by hand that I'd do it. But it actually sounds here like I might be able to get the entire two walls ... 47 feet of wall at 10 feet ... for under $200 .. by a pro! Is that really true?
I would love to use the icf's since I'd get the insulation .... and by code I have to reach R-21 in these walls and so was planninng on having to build traditional 2x6 walls inside and flush against the cement walls.... but, again, I won't be able to get to the outside of the walls in any effective way once they're up since there are neighbors fences only inches away .. so ... donno if that would work. Any one here ever try rastra?
I really DO, again, appreciate hearing peoples sobering cautionary tones regarding attempting a double 10 footer on first time out. It's really great to hear other people's experiences surrounding similar undertakings.
Again .. if a TRULY experienced and skilled guy would do it for '3-bucks-a-brick' ... well .. right now I've got LOTS of time and very LITTLE money .. but that's pretty inviting. Lets see .. that's 529 8x16" bricks ... ~1600 smackola's. Plus rebar, mortar and pumping. A little over 2K. Pretty inviting.
excavation in 3 days!
Thanks-
Terry
If you are legally allowed to build that close to the property line then I'd bet the law would say that your neighbors have to allow reasonable access for construction. Check with a real estate lawyer if interested.
You can build a block wall all from one side, just leaning over each coarse to point the other side.
Have you considered decorative block, such as split-face? It would not require any painting, and would look better for your neighbors.
Don't forget that CMU walls are about the worst thing you can construct for earthquake resistance. So if you live in an area that might get earthquakes, whether required by code or not, you should seek professional advice on reinforcement.
Wayne,
Definitely live in an 'earthquake prone' area ... the Pacific NW is just waiting with baited breath. But his part of the structure is one story only .. so ... But good advice on seeking info on reinforcement .. thanks.
I'll look at decorative block as well.
As for the neighbors .. it's not just them ... it's the fact that I'm building to within less than a foot from wooden fences of theirs. I doubt they'd allow us to take them down for our work ... between the wall and the fence ... innaccessable in the final ananysis. So .. trying to plan ahead.
thanks -
Terry
Newbuilder, being from MD, I know nothing about earthquakes and CMUs - I'd google "quikwall" for info on the dry stack method. Parging involves mortar that is basically smeared, with a trowel, on the sides of the wall. It is still hard work, and cannot be sprayed or painted on.
The $3/block price is what masons charge GCs locally, and you have to know someone to get on the schedule. FHB #111 has a great article on laying up block in the traditional method - perhaps it has made it into one of the Taunton masonry books. If you lay block the regular way, you'll likely still want to parge it for looks. In the NW, I'd look into filling the cores w/concrete or some approved earthquake-proof method.
Sticking rebar in the slab is a good idea, but I always have to cut either block or rebar later b/c I was off a little...
ICFs are typically equal to 6 CMUs each, at $13-15 per icf plus rebar, concrete, pump, forms and time. There is a learning curve, and once the concrete cures, they are relatively permanent. (but I love the result - just built my house with them)
what are you planning to hold up the wall while you work? - blocks aren't exactly stable until tied together with roof structure - and if you're on the property line, you really really don't want the wall to collapse onto the neighbors' side (or dog or kid) - maybe contact a local guy to get some on-site advice - might even be willing to provide some oversight for a fee(?)
6 courses, parge, (structural parging) repeat.
http://www.quikrete.com/diy/QUIKWALLSurface-BondingCement.html
Edited 9/6/2005 6:21 pm ET by Brian
Brian,
GREAT link to the Quickcrete 'parged wall' site.
They make it look/sound (deceptively?) easy! Maybe I'll actually take the time to do it myself! Did you say you had built this way? If so .. how did it turn out!?
Thanks again,
Terry
not a mason, but i've layed some block---I think you will want to have some rebar coming out the tops of your stem walls......you tie in your first row over the bar
Like every 3rd course we always put ladder wire down. Then after finished, dropped in vertical rebar(L bars), and pour filled the blocks every 3 footWhen in doubt, get a bigger hammer!
Yes, my first house foundation - I used "seconds" which was a mistake - the wall was not pretty to look at, but it was to be buried, so who cares. Then I dry stacked a chimney, using chimney block 32' high. It turned out great - straight and plumb all the way up. I used a few brick ties as shims here and there, but everything was tight after I parged. I only stacked 8' a day, parged and waited...
I'll be dry stacking my new garage sometime in the next month or so - Quikwall is $12 or so per bag at HD, and when I run the numbers I come out way ahead, and since I'm still very slow at the mortar approach, I should be done faster.
Surface bonded is reputed to be stronger than regular block construction, but with proper detailing most of the load should be straight down anyway - I am personally sold on the method, although I still fill a few cores with concrete for insurance.
Wow ... I LOVE this idea of stacking and parging. I'm going to really look into it.
REALLY glad I posted the question here and very thankful for all of the feedback!
Terry
It is pretty easy...My husband & I did major repairs on a large barn in 1983 - at the time, he was a short, chubby guy in his 60's, & I was (still am) a 5'6'' female - we were both pretty handy, but nothing special. He stacked, I parged, we took a few days, & the barn is still there, in Youngsville, NY - cold country.
The product we used was called Surewall (what the local yard carried) & I liked it so much I've continued to use it, parging foundations & chimneys, etc.
You could definitely do it by stacking as many courses as you can reach over. It makes a pretty seamless joint with itself, and you won't be looking at that side, anyway :)
Thanks Kate!
Really appreciate the encouragement and love your story of how well it worked for you!
Terry
Terry, block is nasty stuff.
Tears up your hands and your back.
If you have never worked with block, you are not going to believe how long it took to do it when you get finished.
Cheap? No.
Never again, Joe H
It sounds like you are not really asking about the technical aspects of your project and are just looking for some words of encouragement...
I'm a builder, not a mason, and have learned over the years that there are some things that take skills that can only be learned with months or years of practice. Bricklaying (& block) is one of those things. When you watch them, it looks easy - it ain't... If you DIY, it will look like it. Further, I have a pretty wide variety of skills, but when I've tried laying brick & block, figuring my time, vs what I could have hired a mason for I was making about $4 or $5 an hour! So it looked borderline at best and I "made" $4 or $5 an hour... life is too short for that... It's called trying to beat someone at their own game. Fine if I need 6 blocks added to a pier that is gonna be in the crawl space anyway and I don't want to wait for the bricklayer to show up, but not really a "mode of operandi"...
But, wait, your walls are to be 10' tall! So, you will be working off scaffolding after you reach 5'. Make that $3 an hour... unless you can get your wife to keep your scaffolding stocked with block and mortar... ;-) Ok - now subtract out the scaffolding rental, lets go to $2 an hour... OK - so maybe you have a few things wrong... You might even end up "paying" to have this 'rich' experience... :-)
OK - so you say a wall that is 10 x 19 + 10 x 28 = 190 + 280 = 470 sq ft. x 1.125 = around 530 blocks (no waste accounted for), assuming 8"x8"x16" block. OK, so, at a labor rate of say $1.50 a block that is $800. How long does it take you to make $800 at whatever it is that you do for a living?
Sorry - no words of encouragement here, but sometimes this kind of thing can serve as a kind of reverse psychology motivator. OK - so post some pics of the walls when you are done. Take the pics with angled light and camera position and incorporate levels and string lines in the pics. ;-)
BTW - I've never heard them called cement blocks... maybe "cinder blocks", "block", "concrete block" "CMU (concrete masonry unit)" etc - maybe a regional thing. Or, maybe we are talking about a different product?
I think the key word in your orginal post is 10 ft high. I'm a DYI'er and finished doing a 28' X 32' addition. I did the concrete block foundation myself. My foundation was off at most 3/8th in off on the sides and 1/2 in off on the diagonals and 3/8ths off on the height. ( I cheated on the height.. our ground water comes up in the fall. After the footers were in and the first two layers, I measured down to the water level for correction for the story pole.)
I didn't think block was all that hard. Its the set up thats hard (surveying). I did the footers also and setting a string for the ourside of the block and the middle (figuring placement of the vertical rebar) took some time.
My foundation was 4 ft above grade (important) so I didn't have to set up much more than a few blocks on end with planks. I found that if your view and perspective of the string in relation to the block isn't almost perfect, the block won't be level with the string. I'd lay a few blocks, always measure from the end with a tape measure. Making sure the spacing is correct and eye the block with the string. Doing that 10 ft up gets real tricky. Humping all that material up doesn't sound fun.
If done right you'd need to put horizonal rebar in the last or second to last course. Doing that 4 ft above grade is alot different than doing that 6 or 7 ft above grade. After notching the block for the rebar, you have to get concrete in the block.
Dennis in Chicago
You should have used a bond beam block for your horizontal rebar placement. It is a U shaped block without ends, specifically designed for making bond beams. You place the #3 rebar in and slush it with concrete.
On tall walls horizontal reinforcement is added every other course in the form of durawall wire. It is a heavey gauge (#10) ladder design reinforcement that is laid in the bed joint.
Dave
I forgot. If you're new here and haven't been a FHB suscriber, buy the cd with 600 of the best articles. Really great stuff. Your technical questions can be answered there
I don't have time today to read all the previous replies, but my suggestion would be to consider ICF's (insulated concrete forms). They are a do it yourself system if you are competent at building things. Of course, you'll need help with the concrete pour. If you have to lift the concrete you'll be adding more cost, though, and maybe hiring a mason in the first place would be a better idea.
Terry,
ICF's are the way to go!
I just did my first foundation using them and it was
love at first sight. The forms I used are iforms from Reward wall systems. http://www.rewardwalls.com
Incredibly simple to use, fast, logical, no skill required with the exception of having a good head on your shoulders.
Total opposite from CMU's which require skill and are difficult to work with.
You'll have to hire a pump truck but once you are ready to go the pour is nice and quick. For your first time out you might want to take it slow and do the wall pour in at least two lifts, maybe three lifts.
Once you're done you have an insulated wall that can be parged, covered with stone etc. They also have a special form with a ledge if you are going to do brick veneer.
Good luck!
Tom
You Don't Want to Know.
You Aren't Going to Know.
ICF's are fine, but for a 10' wall, a little education is in order.
Some places, like where I am, any structural masonry/concrete wall over 4' requires an engineers stamp. On a CBU or ICF wall, the biggest criteria is the rebar schedule.
When you pour your slab, you need to know what you're going to use (ICF's or CBU's) because you have to place your vertical bar into the footing to align with the cores of the block layout. To do otherwise will cause you much misery later.
ICF walls (the paneled walls are the best), require some attention to consolidation (vibration) and to bracing and the ability to adjust the bracing during the pour.
That's why most of the ICF mfgr's have their own proprietary bracing/scaffolding units. These can be purchased (not economically feasable for a one-off residential project) or rented from some local contractor who does ICF's and may be willing to assist you for a reasonable fee.
I learned block-laying by just doing it, but finally got some pointers from an old pro when I attempted an 8' wall as opposed to the 24" and 32" I'd finally become adept at. A 10' wall would be a real challenge for a novice, not only in terms of maintaining alignment, but just the shear effort of moving block and mortar up onto scaffolding for hours and hours.
I'm getting a bit long in the tooth, but I'd probably take on a 10' CBU wall if I really needed to, but I sure wouldn't do it as a first timer.
(This post intended for newbuilder) sorry.
Edited 9/3/2005 5:21 pm ET by Notchman
In this area anyway, CMU's come in 2 varieties: regular and lightweight. Lightweight cost more, but are worth every extra penny.
Lightweight 8" blocks weight about 38 pounds each.
By noon they weight more.
Joe H
Here 8" regular stretcher CMU's weigh 36 pounds, lightweight are 26 pounds.
10" regular stretcher CMU's weigh 46 pounds, lightweight are 35 pounds.
By noon I've quit laying block for the day, even if I didn't start till 9:30.
by the way .. I'm thinking of measuring, marking, and having rebar embedded along the outside perimeter of the slab to eventually extend up into the cavities of the blocks. Anyone see any problem with this if the calc's are clear and sound? Or .. could drill and epoxy later .. but the wet slab seems like a great opportunity.
thanks!
Terry
You can do it.
Start with about twenty block or so and mix "mortar" with no portland - just lime and sand and water. Practice up laying the block, then take it down and lay it again. The lime "mortar" won't stick, but will still hold together for practicing.
I'm not a mason, but I've layed plenty of block and have used both mortar and surface bonding. I prefer using mortar. As others have said, reinforce with steel and concrete.
It is a lot of work, but... so what?
Do a little research on mortar. There are different types of portland for use in masonry walls and the Taunton book DOES NOT do a decent job of explaining the issue. In fact, it contains a glaring error about masonry cement.
Since you will be doing the work yourself, you won't be laying up to many courses in a day. Because of that, I doubt you'll need to worry about your wall falling over unless you are in a high wind area.
I worked on a house in AZ many years back where they had bought block that had the local redish colored aggregate in it. When it was all laid up they lightly sand blasted it and it looked really good.
Good luck! and do your research!
"A liberal is a man too broadminded to take his own side in a quarrel." Robert Frost