Framing on Concrete Slab Question

[Dennis Putnam]

What is the most common way to anchor sill plates to a concrete slab when framing the walls. I thought about embedding anchors into the slab when I pour it but then I don't see how an assembled wall can be lifted over the anchors without an army to help (20' wall with 2 1/2 people).

I like tapcon screws for fastening to masonry but I don't know if they work as well on something this large (what size would I use?). I'm not sure I want to do all that drilling, especially considering the number of bits I will have to go through. That also kind of excludes lead anchors and lag screws. Then there are nails using a powder-actuated gun but I don't know how strong they are.

I think embedded anchors are impractical for me as well as all that drilling so that leaves one alternative in my mind. What are your experiences?

[Derek Gilmer]

We always built the wall laying on the foundation, then tilted it into place. You can lift a pretty long stud wall with only two people.

[Bill LaPointe]

The reason for anchoring your walls is to prevent lift in high winds. Either put anchors in the footing and/or slab or drill and use expansion anchors. ( I generally end up doing that. Although it is not the best way, I've never had one move yet. You gan rent a good hammer drill very cheaply.

[Keith Harrell]

I built mine on a concrete slab. The concrete guy was suppose to put in screws in the floor so I could just drill a hole on the bottom frame and but a bolt and washer on.
I ended up drilling them after with a hammer drill and it went very quickly. I was very surprised as it only told less than 5 minute per stud. The key is a hammer drill I feel.

I also built the walls before and two of us were able to lift it vertical without much problem but this was only a 20' wall. We attached support arms 2x4 from the top of the wall to ground until we had all four up.

If you have a permit then it may require one type of faster or spacing. I wanted a separate 100 amp power line so I was forced to go the route of a building permit.

[Aaron Wingert]

Not sure what code you're under, but the International Residential Code requires exterior walls to be anchored with 1/2" bolts and 7" of imbedment into the concrete. Spacing is dependent on the code you're under. After the fact, your only options would be to use wedge anchors (1/2" diameter) or 1/2" threaded rod and structural epoxy. If you have a building permit, contact your inspector for direction on what he prefers. It is not uncommon in this situation for the inspector to want to witness the bolts' installation since they were not installed when the concrete was placed, and it would be too easy to use short bolts that lack the holding power needed.

[Jim O'Dell]

Go ahead and embed your j-bolts. When you start building the wall, lay your base plate on them and hit with a hammer to mark the holes, drill the holes, then build the wall. If you are worried about hitting just the right spot, over drill the holes and use a steel plate, if that will pass code. Won't have to lift the wall but about 3" to get over the bolts. Jim.

[Dennis Putnam]

Thanks for all the replies. If your experiences are that 2 people can lift a 20' wall onto embedded bolts then I think that is the best way to go. As for permits, while I want to build it to code, a permit is not necessary when the owner does the work himself here. Not sure I understand the reasoning behind that (perhaps because I'm zoned AG-1) and/or because a storage shed does not require a CO plus will be neither plumbed nor electrified.

[Robert Reece]

I prefer drilling after the fact because those j hooks never go where you want them too. I use 1/2" Redhead expansion anchors and they work quite well. I would drill the holes about 24 hours after you pour the slab, then it's almost like drilling wood. If you wait a few months, you'll be in for more of a job. Definitely get a good hammer drill. I have a little one, but for bigger jobs I rent a Hilti and it's a world of difference.

[Walter Plummer]

There is another anchor system used here in VA. It is flat straps that are set in the concrete like a j bolt. when you build your wall you spread the two straps and set (scoot) the wall onto them, Then they are bent up and over the bottom plate and nailed with joist hanger nails. Thousands of houses built here using this system. No measuring and drilling, if it hits a stud nail it on up the stud.

[Walter Plummer]

Did not think to post a link before. A little different than I remember but the same idea.http://www.strongtie.com/products/connectors/LMAZ-MA-MAB.asp

[Dennis Putnam]

I've not seen those before. That looks like the ideal solution.

[Ray Schwalb]

We've been using these anchors for sill plates recently. Granted it does involve drilling a 1/2" hole, but you can put them where ever you need them, and they meet code in these parts.

http://www.simpsonanchors.com/catalog/mechanical/titen-hd/index.html

[Doug Carpenter]

You don't have to lift the wall up over the bolts. After you build the wall put a 2 by 4 on the slab next to each anchor bolt. stand up the wall then knock out the blocks and it will fall down over the bolts.

For anchoring a wall to a slab it is hands down the strongest method.

Also when you layout your plate you sit it right against the bolts it place. You trace the bolt location and drill the holes. You can't go wrong.

Pound some 2 by 4s down right next to the end of the slab ant leave a couple feet sticking up so that when you stand up the wall it doesn't slide off the slab.

Have fun!

[Dennis Putnam]

I have been researching the mudsill straps. However, it appears all the straps are designed for a single 2X4 bottom plate. I am using a double plate (top and bottom) with the bottom plate being PT. Am I missing something or are there no straps designed for a double plate?

[Brendan Plavis]

Not sure if this is exactly what you were looking for.... But these are some CAD details pulled from Chief Architect....

[Lee Koepke]

We do alot of drilling after the wall is framed up. More efficient use of labor (the crew stands the wall, one man can do the drilling). With a hammer drill it goes pretty quick, bolts about 4' on center.

[Dennis Putnam]

Thanks but I was talking about mudsill straps not J-bolts. Although I have not ruled out bolts I am still interested in the straps.

[Joe Wiliams]

I have been researching the mudsill straps. However, it appears all the straps are designed for a single 2X4 bottom plate. I am using a double plate (top and bottom) with the bottom plate being PT. Am I missing something or are there no straps designed for a double plate?
Just curious... why use a double bottom plate?

[Glen Butler]

Yeah I have only seen double bottom plates on commercial structures.

Just to verify, how tall is the 20' long wall? 8 or 9 feet tall is no big deal to lift alone if you are still young. But when they are taller they get top heavy quickly.

J bolts are the ideal choice. Next best is exopy rods. Then wedge anchors (red heads). Those straps you are looking at would be a pain because you would have to ensure they are in a nice straight line when you embed them in the concrete.

[Jim O'Dell]

To keep from having to lift the entire wall, set some blocks under the floor end of the frame, lift the wall up on them, then scoot over on the J-bolts. Lot easier that lifting the entire weight of the wall. Jim.

[Jim Terrill]

Just curious... why use a double bottom plate?

Well I can't say why in this case, but we always did it when I was framing, 2x PT over the concrete with the foam between that and the concrete. We would get the PT fixed on and squared up, then erecting the wall was a snap, since the wall could be nailed by gun to the PT. I'm sure that you could probably just use a single PT bottom plate, but the minor additional cost for using another pice of KD to make a double bottom plate is minimal. I guess I never really thought about it, I just learned it as "the way" and it seemed to make sense. Then again the contractor I worked for overbuilt everything rather than have it fail later, so maybe that was part of it.

[Dennis Putnam]

That's the way I've always done it. However, I'm rather tall so the extra 3" (double top and bottom) over standard length studs is helpful and minimal cost and effort. Particularly when mounting a tractor or other high seat implement.

[Ben Franz]

Don't know how many bolts you would need to drill for your job - if more than a few, consider renting a roto hammer vs. hammer drill. It's night and day for speed and effort needed.

Another caution - PT lumber is now almost all ACQ which is corrosive to conventional metal fasteners. When we frame with J-bolts we use a short piece of PVC as a sleeve around the bolt (inserted after placing the plate/wall in an oversized hole) and the wall is nailed at the plate with at least HDG nails. Stainless steel would be even better if your last name is Trump. Any Simpson connectors that touch the PT need to be Z-Max coated line for higher corrosion protection.

If you build in New Mexico, all of this is moot and you just do whatever you want. We don't need no stinkin' codes.

[Ken Garlock]

Go ahead and embed your j-bolts. When you start building the wall, lay your base plate on them and hit with a hammer to mark the holes, drill the holes, then build the wall. If you are worried about hitting just the right spot, over drill the holes and use a steel plate, if that will pass code. Won't have to lift the wall but about 3" to get over the bolts. Jim.

Jim is 100 percent correct. In addition, I suggest treated wood for the base plate.

We used SIP panels when we built. the base plates were provided by the SIP manufacturer. The framers did as Jim suggested above with the addition of a moisture barrier between the concrete and the base plate. Once the base plate was in place, the framers lifted the panel in place and shot a bunch of nails horizontally through the lower lip of the panel and into the side/edge of the base plate.