Block Foundation - HELP needed

[EL-Rebar]

I am contracting out a new home. Hadnt planned on doing it this way but thats how it turned out. I have a sub digging the footing today... Question about the foundation - it will be constructed of concrete blocks, the lot is a sloping lot and will have a walkout basement foundation. The walls near the rear of lot will be fairly high. How high can concrete block walls be built safely? I have been checking out lots of new homes here and the tallest one I have seen was 22 courses - it had no rebar in it but used durawall wire mesh on every other course. No concrete was used to fill any blocks either. I am planning on using durawall mesh as well as running vertical rebar every 4 feet or so and filling all holes with concrete using a pumper truck. Is this overkill and will it stress the footer too much?

The inspector has required me to use L-Rebar coming out of the footer to tie in vertically to some of the walls that will be backfilled. Does anyone know of a sure method of making sure the L-rebar will line up with the blocks once the block mason shows up ? I have heard they will chip and break the blocks and bend the rebar to make it fit - there mus t be a better way. I have spoken to several footer and block guys but they didnt know a sure way it seems... inspector doenst want me drilling and using epoxy;..

Also, the garage will be on the main level, so I need to raise it about 6 or 8 feet - which means that the footer and 6 or 8 feet of concrete blcok wall will be buried right at the entrance to the garage - how do I go about buiilding this block wall and still be able to fill in the garage area with dirt and gravel to 8 feet? A bobcat wont be abel to get in there once the wall is built...

Thanks for any help

El-Rebar

[Rich]

As much as I would like to help - this is a little over my head. I've done masonry walls but nothing where it would be considered much of a structural element of a home. Hopefully Shanley will stop by and give us all a lesson.

[Shanley]

Once the footing is formed find the center line (CL) of your cmu wall and install horizontal rebar (20'-30' lengths) in the confines of the footing along CL you can use short pieces of rebar hammered into the ground and tied to the horizontal bar to keep it stable. Find the corners of the cmu walls and measure in 4" and install a 90 degree (L) rebar using twist ties to the horizontal rebar. 3 or 4 evenly spaced ties should secure the 90's. Starting at one corner measure every 4' from the corner vertical rebar and install a 90 in these locations. Let your mason know what corner you started from if your foundationj isn't on bond (a multiple of 8"). Make sure your mason installs a reinforced knock-out bond beam course at top of wall and installs your plate anchors in it (ie.anchor bolts, strap anchors). Hope this helps

[Shanley]

I need more info...for instance will the area in front of the garage be back filled before or along with the inside

[Shanley]

you might want to have your mason come by prior to pouring the concrete...he may want to tweak your layout a little...also use durowall every other course with prefabricated corners which are readily available at most masonry supply yards

[Rich]

That just reminded me .. there was another post on laying out rebar for a masonry wall I did awhile back. Not sure if it's the correct way to do it - but it made sense to me.. haha.
http://www.construction-resource.com/forum/viewtopic.php?p=111#111

[Shanley]

That just reminded me .. there was another post on laying out rebar for a masonry wall I did awhile back. Not sure if it's the correct way to do it - but it made sense to me.. haha.
http://www.construction-resource.com/forum/viewtopic.php?p=111#111

In my opinion it is best to have the rebar installed prior to the concrete placement...However, in some cases wet sticking is the best option.

[Rich]

Good point.
I'm used to cast in place walls and have always wet-set them as they always seem to be in the way when finishing. Not that either is right or wrong - just what I'm used to doing I guess.

[EL-Rebar]

Well we have the footing in now with the L rebar in all the areas where backfilling is planned. THanks for the help. Block mason has been by and seems pleased with the plcaement.

My lot is sloped and the rear footing is 17 steps (blocks) lower than the front (highest) footing. So the rear wall will be 17 block courses higher than the front most wall when leveled at the main floor. I want to have the front wall 8 or 9 blocks high to get it close to street level (im on the low side of the street on a hill lot). So the rear wall will then be 25 or 26 courses. Would like advice on constructing this wall - most walls around here use only Durawal welded wire mesh every other or every 3 courses with no concrete filling any voids. Would dropping in rebar every third or so block cell and filling with rebar be sufficiently strong? Should I use both rebar, concrete and durawall mesh? Should I fill every void with concrete? Do I need horizontal bond beams, and if so what spacing? The footing is 24 inch wide by 12 inch deep. Is a 26 course block wall filled with concerte and rebar adding too much stress to that size footing? Thanks again for any help and tips.

[Rich]

EL-Rebar
I can talk about the footing and what my opinion is...
The footing size will be fine IMO. Just to give a little comfort for you - a typical one story house doesn't even need a footing if you go by code and a true structural design. In light of that I've always built them with a 16-24" wide by 8" deep footing.. which I also use for 2 story homes. Remember that the footing sizes mentioned are with full CIP concrete walls. So your 24"x12" footing will be more than adequate IMO.
My personal preference would be to full fill all voids with mortar and vertical rebar. It may be overkill but I'd rather pay the extra now than have to pay 10x the extra later. Shane will have a better idea on this though.