T footing and stemwall… your technique
I’m about to form a simple rectangular footprint for my shop. Specs are for an inverted T footing with a stemwall on top… typical stuff. Footing is 16″ wide x 8″ thick, stemwall is 8″ wide by approx 12-18″ tall. For better or worse I’ve done relatively little concrete formwork, especially foundation stuff.
Locally, the guys I know form these in two ways. One is to form the footing first, pour it with rebar sticking up, then form the stemwall on top and do a second pour. The other is to form the footing, nail 1×4 PT cleats across the top of the footing forms approx. 24″ OC, nail metal spreader cleats on top of the wood cleats, and form the wall on top of the cleats. Only one pour this way. The 1×4 and the metal cleat are left embedded in the concrete.
For various reasons I want to do one pour, mainly to avoid a cold joint and to get it over with more quickly. I have some distaste for wood left embedded in my foundation, although the AHJ allows it and it’s done all the time here.
Anyone got other details they can share?
Replies
No expert, but seems to me to be a bad idea to have embeded wood in the foundation. It will rot, invite carpanter ants, and eventually leave a hole throw the foundation. As strange as it is, mice or shrews or gophers will find the holes. Of, course they can burrow deeper and go under teh footer as well.
Just my thoughts, but I am sure people have actaul experience with this stuff.
That is how 95+% of all foundations are installed on the Wash Coast. The Footing is poured, cleats are embeded in the top of the footing with just a nail. The next day the panels are set. Following day, walls are poured. Only thing holding the walls to the footing is the verticle rebar, not even a "key". Two #4's horizontals in the footing and one #4 in the wall
IIRC, the verticles are straight rods , no bends or "J"'s. Had me scracthing my head when I first saw this. I'm origionally from So.Calif.
Not a whole lot of seismic activity on the coast, or at least till a big one hits
Here are the cleats they use: http://www.awardmetals.com/FormClipChart.htm
Edited 2/1/2006 4:48 pm by migraine
use galvanized metal hat bar instead of 1x4 for your cleats. it's a standard inexpensive material available from metal stud suppliers.
the "U" shape will fill with concrete when you pour.
you can double it up if you are worried about it's support strength.
carpenter in transition
Your neighbor Jim Blodgett had a piece in FHB magazine awhile back detailing the kind of monopour you want to do.....about a year ago, IIRC.
david,
There is a quick way to do this but it isn't approved by any code that I've heard of. It will give you a footing that is 11" across at the bottom, which is not much but can be enough in the right soil conditions.
Most ICF form manufacturers have a "taper top" block available in which the foam is thinned out on both sides at the top. There's a drawing here:
http://www.logixicf.com/client/LogixICF/TechMan.nsf/TechnicalFrameset?OpenFrameset&Manual=CAD+Drawings
Prepare a good, level, well-compacted, crushed stone bed at the bottom of you trench and install a course of these things upside down, tying them to each other. Install however many courses of standard blocks and steel you need to get your height, tying the standard forms to the first course. Backfill very gently to cover the taper top forms. Pour concrete.
I would use Integra spec for a job like this mainly because those forms don't have a top or bottom. The interlock pattern is the same on both edges.
Ron
I've formed and poured a few monopours like you ask about, David. I looked around but haven't found the CD full of photos for that article. That would really illustrate things better than words. I have to go back to work, but I'll try again this evening. In the meantime I'll try to attach some text that might help you foresee potential problems. TIPI,TIPI,TIPI!