I’m building a garage and my concrete contractor istalled y-shaped galvanized foundation anchor straps rather than anchor bolts. Unfortunately, he did not pre-bend the straps before placing them in the concrete, and so now there is no way that the mudsill can sit firmly on the slab (as it will be siting on top of the bend straps). My thought is that I should just cut them off with a hacksaw and attach the mudsill some other way. Does anyone have thoughts on acceptable ways to do this? I was thinking I could use those blue tapcon screws. I’m a little scared to use a powder acutated fastener as I will be driving it so close to the edge of the slab – but maybe someone could put my worries to rest about that.
Thanks -John
Replies
Bolt them down with lags and expansion shields.
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Edited 12/19/2006 4:02 pm ET by JDRHI
Take a close look at those straps - are there letters/numbers on there? Like "LMA4" or something similar.
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
One side of each "branch" of the Y says USP, the other says ST1.A friend suggested I drill holes in the mudsills, pass the straps though the hole, and the bend them over the top of the mudsill the nail them down. Instead, I could also route a series of shallow grooves on the bottom of the mudsills so that that I could bend the branches of the straps out first, and still lay the mudsill down flat on the slab.
I've seen guys do it the way your friend suggested. I don't really think that is the correct way though. If you are worried about the metal holding the mud sills up 1/16" of an inch or so, if you use sill seal this will not be an issue, since the sill sill is roughly 1/4" thick and really doesn't compress as much as you would think, but would compress where the anchor straps are. http://www.dow.com/styrofoam/na/res-us/products/sill_seal.htm As far as I'm concerned, you should be using sill seal anyway as it help keep the bugs, and cold air out, (granted, cold air may not be a concern with a garage) and it also functions as a capillary break to help to keep moisture from being wicked up into the framing from the concrete.
Take a look at this:http://www.uspconnectors.com/discontinued_products/36-37and210.pdf
What you need to do is drill a 3/4" hole in your sill plate where those anchors are, feed them through the hole, then bend them DOWN OVER each edge of the sill. The way you mentioned doing it - bending them flat to the concrete then wraping them up around the sill is explicitly wrong according to USP.Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Tap cons are probably not allowed depending on what wind zone you're in. Check with the inspector to see what will fly if the straps are totally useless.
Hilti and others make epoxy to be used with threaded rod as anchor bolts.
Are you sure the straps are not usable? It's a little hard for me to picture from your description. How much would the straps hold the PT mud sills up off the concrete? As Paul said, what is the model number of the anchor straps you have?
Tap con's are not adequate for attaching a building to a slab foundation. You need 1/2" bolts of some kind. How about something like these: http://www.confast.com/products/thunderstud-anchor.aspx You need a good drill to install them though - really a rotary hammer. You would frame your walls and stand them up, then nail the plates to the concrete with cut nails, or if you wanted to use your Power actuated tool, that is fine too, just stay at least 2 1/2" away from the edge of the concrete. You are going to set your mud sills in 1/2" for the sheathing right? Anyway, once you have built and nailed down your walls, you come back and drill for the 1/2" concrete anchors.
Matt,Thanks for the reply and suggestion. To try to give you a clearer picture, the straps should have been pre bent into a "Y" shape so that once embed in the concrete, two parallel staps protruded about a 2X4's width apart. Instead, the contractor didnt bend them at all so the two straps are right next to each other. Now I have to bend them apart, so that they lay flat on the slab, lay the mudsill on them, and then bend the protuding length up around the bottom of the sill. The sill would be sitting on the straps and elevated 1/4 inch or so unless I hammer those bends really flat.
The way your concrete sub did it is the only way I've seen it done. Hammer them down flat. That is the way they are intended to work.
BTW - the sill seal stuff is cheap. I'm thinking less than $.10 a foot. I use it on interior walls and all...
Yeah, I guessed he was going by what he had been taught to do. When I was inspecting his work, the day after they finished pouring, I found the instruction sheet for the anchors and glanced over it. It clearly states that the straps should be bent before embedding and that leaving the sticking straight up is the wrong way to put them in. You guys have convinced me though - I'm just going to hammer them flat and use them with the foam sill sealer and not worry about it unless the inspector says something. If he does I'll do as other replies have suggested and use something like the thunderbolt.Thanks to everyone for all the help. -John
I'm not doubting your instruction sheet, but I've installed an awful lot of mudsills with those straps and never seen them pre-bent before. Hammer 'em home.View Image
>> I found the instruction sheet for the anchors and glanced over it. It clearly states that the straps should be bent before embedding and that leaving the sticking straight up is the wrong way to put them in. << Right, but then the concrete finisher possibly wouldn't have been able do as good finishing around the anchors, and then you would have a different problem. Personally, I don't necessarily always take the manufacturer's instructions as the best way to do something - most of the time, but not always... We don't use these type of anchors around here any more, but in the past, I found that to have them just somewhat bent on install gave the best result. Go ahead and hammer them down while the concrete is somewhat green. Don't get too carried away with the hammer though... The situation you face is the reason I never really liked those kind of anchors.
Yeah - it's typical for the block or crete guys to leave the straps just as you describe them.
You just have to separate them and bash 'em flat with a hammer.