Foundation anchor bolts - New construction


First post here. I will be the homeowner of a new tract home in Central NY (Manlius). When the foundation subcontractor built the block foundation they set the anchor bolts too deep in the concrete. As a result the framer could not get nuts and washers on those bolts - I would say about 60% of them.

The house is almost completed and they were getting ready to install sheetrock in the finished portion of the basement when I pointed out (3rd or 4th time) that this was a problem. The building inspector also flagged it back in the fall.

I am confidant that the builder will make the sub fix it but my question is - how do I want it fixed? I think IRC 403.1.6 would apply. It calls for 1/2" bolts 7" deep in the concrete block, every 6’ with one at each end.

These are hollow block that had concrete poured in them every so many feet. Do I want them to drill through the 2x6 into that poured section and install a bolt? Either an expanding type or epoxy?

Any advice would be appreciated.

In my experience there are often instances where the original anchor bolts are unusable or in the wrong place. The common fix is a 1/2" expansion bolt drilled in the foundation. If they can still see where the short bolts are they can drill and hit filled blocks there. You may want to talk to the building inspector as this is a code violation. The fix should be inspected by the municipality.

If they are proceeding with the drywall installation without implementing an anchoring solution, I would contact the AHJ (building official) and ask them what to do about it.

There are sleeves available that can extend the threaded bolt

Also called couplings

Firstly, if the bolts were too short to get a nut on, same would be for the coupling. Secondly, if you could get the couplings on, that would prohibit the nut from tightening down to the sill plate.

A box of appropriate sized washers and some bolts (or threaded rod) of varied lengths, depending on how accurate they set the anchors, would do the trick.

Bottom line is that if you can’t get nuts on the existing anchor bolts as the OP stated, then none of what you suggested will work.

If the building inspector flagged this already, why wasn’t it fixed then and reinspected? Sounds like an engineer will need to spec the retrofit if the existing anchor bolt’s are too short for chiseling out the bottom plate a bit.

Well since they are in the stage of drywall and now the sill plate is no longer accessible to drill, add bolts, chisel the plate and what not to repair, this here might be the only alternative that is accessible.



You may be correct. I was assuming that the OP meant that he couldn’t get the washers and nuts on with the sill plate in place. But, who knows what he meant?

Marcel’s remedy removes the need to assume…:slight_smile:

A box of appropriate sized washers and some bolts (or threaded rod) of varied lengths, depending on how accurate they set the anchors, would do the trick.

with engineer approval simpson has a number of options for sill plate anchoring retrofit

OP here. Sorry for not responding earlier. Notifications went to my spam folder.

Builder chiseled out enough of the 2x6 to get the nuts on most of the bolts. Thanks for the responses.