Exterior walls on a concrete slab questions

[Steve_B]

Stopped by booksamillion and picked up the house framing book suggested by the site here, but still have a few questions about framing

First question is.... I know J hooks are set in the slab every 6' apart to bolt the wall down with, but do you still need to drive nails into the slab to hold the exterior walls in place?

Can't seem to find any information on this.... if so, what type, and how far apart?

[Redoverfarm]

The nails are normally driven in with a Hilti gun.  They have nails which range from 14mm-50mm .  Most contractors that I have worked with usually do not use "J" bolts in a slab construction.  They generally use them in block foundations and the J bolts are held in place by concrete or mortar in the block webbing.  Most use Hilti fastners on slabs.  But if you choose to use J bolts attempt to place them at locations where there will not be a stud (in the stud bay).  I would probably place the concrete nails at 2' intervals between the "J" bolts.  If you just used J bolts there is too much area not attached at that 6' intervals.

Another alternative would be wedge bolts.  Make sure the concrete has had sufficent time to cure out before using the Hilti fastners or wedge bolts.

[MountainDon]

I've never seen anything but J-bolts in new construction around here.

Here's the IRC....  bolts, not nails...
http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_4_par023.htm

    R403.1.6 Foundation anchorage.
    Sill plates and walls supported directly on continuous foundations shall be anchored to the foundation in accordance with this section.

    Wood sole plates at all exterior walls on monolithic slabs, wood sole plates of braced wall panels at building interiors on monolithic slabs and all wood sill plates shall be anchored to the foundation with anchor bolts spaced a maximum of 6 feet (1829 mm) on center. Bolts shall be at least 1/2 inch (12.7 mm) in diameter and shall extend a minimum of 7 inches (178 mm) into concrete or grouted cells of concrete masonry units. A nut and washer shall be tightened on each anchor bolt. There shall be a minimum of two bolts per plate section with one bolt located not more than 12 inches (305 mm) or less than seven bolt diameters from each end of the plate section. Interior bearing wall sole plates on monolithic slab foundation that are not part of a braced wall panel shall be positively anchored with approved fasteners. Sill plates and sole plates shall be protected against decay and termites where required by Sections R317 and R318. Cold-formed steel framing systems shall be fastened to wood sill plates or anchored directly to the foundation as required in Section R505.3.1 or R603.3.1.

    Exceptions:

    1. Foundation anchorage, spaced as required to provide equivalent anchorage to 1/2-inch-diameter (12.7 mm) anchor bolts.

    2. Walls 24 inches (610 mm) total length or shorter connecting offset braced wall panels shall be anchored to the foundation with a minimum of one anchor bolt located in the center third of the plate section and shall be attached to adjacent braced wall panels at corners as shown in item 8 of Table R602.3(1).


And they use large washers, sometimes square ones about 3 inch square.

    3. Connection of walls 12 inches (305 mm) total length or shorter connecting offset braced wall panels to the foundation without anchor bolts shall be permitted. The wall shall be attached to adjacent braced wall panels at corners as shown in item 8 of Table R602.3(1).

[Don_P]

It takes a minimum 1/2x10" long HDG, hot dipped galvanized J bolt at the spacing being quoted or in many jusisdictions tighter spacing.

What I really wanted to write about was the practice of "wet stabbing" anchor bolts. That's when you make the pour and then walk around sticking the anchor bolts into the fresh concrete. Yes it does help to jiggle and reconsolidate the mud around the bolt but you have just pushed all the aggregate that should be over the hook locking it into the chunk of concrete down under you. The bolt is basically covered with cream. If you can support the anchor bolts prior to the pour and place concrete around them they will be much stronger. I have withdrawn anchor bolts when bolting down several times. Hooking them under a rebar in a slab would really tie them down.

[MountainDon]

Funny that you mention that Don. The guys that did the monolithic slab our house sits on had the j-bolts all wired to the remesh. They used 5/8" too IIRC. When it was all said and done they did have to wiggle a few  to get a good vertical lineup but that was minimal. Italian owners.

[Steve_B]

Thank you for all the replies...

Next question is.... I am assuming that interior non load bearing walls would just be nailed to the slab and the exterior walls where possible?

[Don_P]

That is fine, hilti's, tapcons or redheads are all pretty common there. I don't like to but have simply glued the plates down over radiant slabs when we didn't have a good map to positively avoid the tubing.

[EvoQ]

Can I ask WHY you are doing a Slab type construction for such a small cabin ? I would never do a slab, ever for a small cabin. Way too many issues with slab type construction.

[MountainDon]

Issues?  I've seen issues with piers, crawl spaces and full basements of poured concrete and blocks too.  Slabs are simple and fast and when laid over a couple of inches of XPS foam they are also warm in winter. Perfect for radiant heat too. I may have a bias towads them though, as we've lived on one for coming on to 28 years. Had a basement for 11 years before that that gave me more headaches.

Of course my part of the country is well suited to slabs; not too much depth needed to be below frost depth. Monolithic are great.

[Steve_B]

Can I ask WHY you are doing a Slab type construction for such a small cabin ? I would never do a slab, ever for a small cabin. Way too many issues with slab type construction.

Not really thinking of it as a cabin as it will be close to 1400 square feet and be our primary residence... for the concrete slab installed, including all materials and grading, it costs me $3,500

Factor in the cost of me hand laying a block wall, mixing tons of mortor, and countless hours of labor, and all the wood to build the base and subfloor.... and I bet the price would be very close!

I am trying to do as much labor myself as the budget is very tight.... concrete slab can be laid in one day.... me doing the crawlspace myself would take many weeks including laying the subfloor and all the beams

Slab is the way to go my man!!!

AND I may just have the concrete tinted a color and use that as the first floor and save the $$$ on flooring costs which would greatly improve the value of a slab being installed!

[MountainDon]

Steve, have you looked at concrete staining?

http://www.directcolors.com/concrete-stain/?gclid=CLaqr7vbuLQCFcU-MgodfjcAow

That's just the first site that came up on a 'google'   ... no recommendation per se.

[Redoverfarm]

Steve although CWhite has not been on here in a while you might send her a PM and ask her about the process that she did concerning staining her concrete floors in her build.  Hopefully she will have her E-mail notification still turned on and will pick up on your message.  Her building thread is the following.  Not sure where in her build she describes the process but it turned out good.

http://countryplans.com/smf/index.php?topic=2991.msg94855#msg94855