Hold-down type
joenorm
| Posted in General Questions on
I have 12 hold-downs to install in the stemwall for a new construction home.
Engineer has given option of embedded strap type or or drilled and epoxied HUD type.
I see advantages and disadvantages to both. As far as green building is concerned it seems like straps are better as they do not take away insulation space like the HUD style would.
Any preferences here? Thanks
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
The HUD style are better from a durability aspect and more likely to be installed properly. You should skip the epoxy installation and wet set the holdown anchor bolts when the wall is poured. Epoxy is $$ and requires special inspection to install.
Joe,
Are these seismic hold-downs, or just anchor bolts? If they are anchor bolts, like Tim I'm surprised that installing them during the pour wasn't an option. If they are for seismic their location is so specific they are almost always drilled in after and epoxied - and that's the way I'd go.
The problem with wet setting the anchor rods is getting everything to line up. Generally speaking using Hilti HY200 or Simpson ATXP epoxy is pretty straight forward. A lot of these hold downs require multiple stud packs and getting the wet set anchor rod to line up with the framing doesn't always happen.
Wet set anchors are cheaper. Have the framer place the anchors, they will get them in the correct place. They wet set holddown anchors all the time in Southern California. you have to plan ahead.
The Epoxy anchors require a special inspection by code. Here it is a 1/2 day min so like $400 per inspection. Plus $45 buck per tube epoxy
Tim,
We use these Simpson hold-downs on each end of a shear-wall and often the double studs also frame one side of an opening. The bolt location has to be spot on. I couldn't set one exactly enough doing the pour. Luckily there are no separate inspections for epoxied bolts here.
https://www.dhcsupplies.com/store/p/3681-HTT5-Tension-Tie.html
Thanks All,
The option to wet set the anchor bolt is there for sure. I just figure it's tough to get them in just the right place.
These are uplift hold downs, not for seismic.
I might try the strap type and wet set them.
The strap type require you to get them in the exact location on the holddown lumber. How is that different from getting the bolt in the correct place?
See the simpson link below for installing the HD off the plate & angling the bolt back to the HD. I have seen the strap type corrode at the concrete interface & spall when bent. I don't like them.
https://www.strongtie.com/products/connectors/wood-construction-connectors/technical-notes/general-notes-for-holdowns-and-tensionties
The other problem I've had with the strap connectors is they cover a lot of the face of the stud, effectively making it a no-nail zone for sheathing or trim. Particularly annoying when it is located at openings.