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sill plate anchor depth

Dorthorus

Registered User
Joined
Nov 21, 2020
Messages
1
Location
Virginia
I'm replacing a rotted sill plate. How deep into the foundation do the wedge anchors have to be drilled?
 

cda

Sawhorse 123
Joined
Oct 19, 2009
Messages
19,058
Location
Basement
Welcome

would give till Monday or Tuesday for an answer.

Are you in a flood or beach area?
 

Joe Engel

Member
Joined
Jun 16, 2011
Messages
50
Location
MIssissippi, NW
IRC says, 7" embed (don't have my code book handy to quote section/verse). After they are installed, generally an inspector can't tell the length unless a sample is left laying around. Most builder/carpenters in my area like to use the 4-1/4" redheads but I recommend at lease 5-1/4" with no more than 3/4" of thread above the nut after torque applied. That would put the depth of the hole at 3". 1-1/2" or less, could blow out the top of the slab under stress or even just tightening the nut.
 

Mark K

Platinum Member
Joined
May 12, 2010
Messages
1,707
Do not believe the IRC provides for the use of post installed anchors. What the IRC says about cast in place anchors is not directly applicable to post installed anchors. Thus you would have to reference the IBC which in turn references ACI 318 which provides a standard to be used in qualifying the anchors. The results of the qualification process should answer your question.

The mechanism by which a wedge anchor transfers forces to the concrete is different than that of a cast in place anchor, thus the length of embedment should be different.

Individuals have a tendency to apply the IRC to situations where the IRC was never intended to apply to.
 

ICE

Moderator
Joined
Jun 23, 2011
Messages
9,264
Location
California concrete jungle
Expansion anchors vary in the torque value that is required. We require 5/8" anchor bolts. The lowest torque value is a Hilti anchor at 60 ft.lb. Red Head and most others is 90 ft.lb.

So that's not to say that they can't be used with lumber. The anchor must be installed without the wood in place. If the sill is installed, drilled and a washer is placed with an expansion anchor that is then torqued.....the wood fails.
Looking at any depiction of the expansion anchors in any product literature..... the application is for anchoring something made of steel.
If you see an expansion anchor with wood, ask for the torque wrench. What you will find is that the nut was tightened until the sound of wood crushing made them stop.
 
Last edited:

mark handler

Sawhorse
Joined
Oct 25, 2009
Messages
10,842
Location
So. CA
The size and depth, depend on the loads imposed.
We do not know the required loading on that wall, is it a lateral load resisting (Shear) wall? we do not know the condition of the concrete.

Regardless, you may want to use stainless steel (Types 303/304; Type 316).
 

mtlogcabin

Sawhorse
Joined
Oct 17, 2009
Messages
7,837
Location
Big Sky Country
 
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