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HighDesertHomeOwner 03-18-2011 02:36 PM

Installing expanson anchor bolts
Can I simply place expansion anchor bolt into the concrete before it sets?

Do I have to drill on the concrete after it is set?

Or is it best to insert slightly small diameter rod, say 7/16, and just drill slightly to 1/2 inch for 1/2 inch anchor bolts.

I am talking about the type of anchor bolt that expands as you tighten. It is first pounded into the concrete, but as one tightens the bolt expands in diameter.


Also, are this type of anchor blots good for pressure treated lumber sill?

nealtw 03-18-2011 03:39 PM

You can buy concrete bolts made to put into wet concrete and they are much cheaper than ancher bolts. Either way just buy plated or dipped bolts. We order bolts from the concrete company , they come with the ready mix trucks.

joecaption 03-20-2011 07:21 AM

It would be best if you told us what it is your really trying to do this for. Is it a new slab that's being pored, an old slab that your adding walls to ECT.
If it's a new wall you all ways install the foundation bolts as it's being pored.
If its an old slab then you can drill and set the bolts in epoxy (there sold in any box store in the same area the Joist hangers are sold) or even just use Tap Con screws.

HighDesertHomeOwner 03-21-2011 01:56 PM

New slab for a small 7.5'X16' shed but in a windy area.

The slab will be 4" thick with many rebars.

I will be using PT 2x4 as sills.

Shed roof with combined rafter/ceiling joists in the same piece of 2x4.

Two bird's mouth cuts on each rafter/ceiling, the span of the two bird's mouth cuts is 7 feet.

HighDesertHomeOwner 03-21-2011 02:01 PM

I just realize that may be pouring in just a small amount of epoxy, as little has half a teaspoonful, into the anchor hole and then tighten will greatly strengthen the bolts. It won't loosen.

mudmixer 03-21-2011 02:17 PM

Any Santa Anna winds?


HighDesertHomeOwner 03-22-2011 12:12 PM


I have decided to not use wedge expansion anchor and to use L shape cast in bolts.

0.5 inch and 6 inches long. I will leave 2.25 inch up. I figure 1.5 inch for the PT 2x4 leaving 0.75 inch for the nut and washer.

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