Mudsill, or sill plates, makes the transition from concrete piece of work to wood framing and anchors the firm to the foundation. When I started coming to the jobsite equally a teenager in the early 1990s, we anchored our mudsill with 1/two-inch bandage-in-place ballast bolts placed 8 anxiety on-middle. Just a standard washer and nut was required to attach it. That changed for us in the early 2000s, when edifice codes in our area were updated to meet seismic zone requirements and began to require anchor bolts spaced 60 inches on-heart with 3x3x1/4-inch plate washers. Since and then, several other options take been recognized in the code, and we've tried them all to figure out what is well-nigh efficient for us.

Alternatives to Anchor Bolts

The basic prescriptive requirements of R403.1.vi in the 2015 and 2018 International Residential Codes (IRC), call for minimum 1/two-inch-diameter ballast bolts. These bolts must extend 7 inches into the concrete and be spaced no more than half-dozen feet on-eye. In seismic zones, these bones requirements apply with the addition of 3-inch-square plate washers. However, in all cases, the building lawmaking as well allows for the use of "approved anchors or anchor straps spaced as required to provide equivalent anchorage to one/two-inch-diameter ballast bolts."

For a number of years, nosotros used Simpson Strong-Tie MASAP mudsill anchors, which qualify equally an approved substitution for ballast bolts with 3-inch-square plate washers. These seemed similar a good alternative to having to adjust the layout for joists that landed on bolts. They attached easily to panelized concrete forms, and we didn't accept to worry almost the joist layout. The MASAP is located at the border of the foundation wall and wraps over the border of the mudsill. This placement has the advantage that we could set the mudsill right on our snapped layout lines—a welcome change from aligning ballast bolts, which takes time to practice accurately. Allowable holes for the anchor bolts in mudsill can't exist oversized more than one/16 inch, and and so we often would end up having to movement the mudsill slightly to accommodate the ballast bolts, and the mudsill would stop up off the line.

With MASAP straps, we used a Hilti powder-actuated tool to secure the mudsill to the concrete on our chalk lines. This held it in place until we nailed off the straps. Nosotros used MASAP straps for nearly x years, nailing them off either with a positive placement gun or by hand-nailing. Frankly, this was tedious, and we needed to pin the plates in identify with the Hilti to keep them from moving around when we nailed off the anchors. Another disadvantage is that the MASAPs created a gap between the mudsill and the rim joist that bears on meridian of it. All things considered, we ultimately went back to the ballast bolts, feeling they were cleaner and simpler to apply.

Making Anchor Bolts Work

Nosotros sometimes sub out our foundation piece of work, but typically we form and cascade foundations ourselves. I lay out the location of the bolts prior to placing concrete, and my focus is to eliminate any framing landing on bolts or plate washers. Much of our framing is 24 inches on-center, so the bolt placement is 48 inches on-heart and lands between joists or studs. I use Simpson Strong-Necktie'southward AnchorMates to concord the bolts in place. These bolt holders are made of nylon plastic and concord up well over fourth dimension and then they more than pay for themselves. (We have been using the same gear up for the terminal ii years.) Though not required, the bright blue holders also give the inspector something to see, and overall they make for one less thing for us to deal with during the pour.

Aligning the mudsill tin exist a challenge, just over the years we have worked out some adept processes. The virtually important part is getting the foundation right to begin with. I have outlined our foundation process in a two-part series, "Building Stem Wall Foundations," Feb/13, and nosotros cover it regularly on Instagram at @awesome framers.

Working in a D2 seismic zone, the author is required to use 3-inch-square plate washers on anchor bolts. To save time, he tightens the nuts with an impact ratchet, being careful not to overdrive the nuts, as that can crack the concrete around the bolt. The rule is to seat the nut, then tighten it one half-turn.
Working in a D2 seismic zone, the writer is required to utilize 3-inch-square plate washers on anchor bolts. To salve time, he tightens the basics with an touch on ratchet, beingness careful not to overdrive the basics, every bit that can crack the concrete around the commodities. The rule is to seat the nut, then tighten it one half-turn.

To align the mudsill with our chalk lines, nosotros place the sill board side by side to the anchor bolts, center a square with the bolt, and mark a line beyond the board. The bolts are non e'er perfectly vertical, so you have to eyeball the base of operations of the commodities. When the locations are marked, we slide the board back to the chalk line and measure the distance from the base of operations of the bolt to the edge of the lath. We then mark this altitude on the lath and drill our holes. The largest hole we tin can drill for a 5/8-inch-diameter bolt is 11/xvi inch.

The Case for Drilling
A few of us framers on Instagram have been talking about ditching anchor bolts completely and drilling them in after the concrete is poured. There are a few options available that work for this in our seismic zone: Simpson's Strong-Bolt 2 wedge anchors (or similar from other manufacturers) and Titen HD screw anchors are two that we've used. Both are allowed as alternatives to cast-in-place anchor bolts, simply there are some caveats.

The idea of drilling after the fact might seem on its face a slower method, but in that location some definite advantages:

  • Drilling later on the fact means we never accept to motion a framing member or notch information technology. Many foundation subs don't think about the framing; they simply fix bolts to the spacing called out on the plans. This means that when we sub out our foundation, nosotros sometimes terminate up cutting ballast bolts off and drilling for Titens anyway.
Kyle Davis of Pioneer Builders tightens down a Titen HD screw anchor.
Kyle Davis of Pioneer Builders tightens down a Titen Hard disk drive spiral anchor.
  • We don't accept to even recall about laying out bolt locations while forming the foundation.
  • Mudsill can exist set perfectly on the line and no holes volition be oversized since the size of the hole for the anchor is exactly the same size every bit the anchor.

There are a few cons to drilling after the fact, though:

  • The AHJ (potency having jurisdiction) might not permit it as the sole attachment method.
  • Even if code allows the anchors on paper, inspection of the length can be an issue. The Strong-Bolt ii has the length stamped on the finish, merely Titens don't. Additionally, the Stiff-Commodities 2 has a torque requirement for the nut, which the inspector might want to verify.
  • You can hit rebar when drilling. Rebar can be time consuming to drill, even if you apply my favorite rebar-cut bit -the Diablo Rebar Demon.
  • Even if yous don't striking rebar, it's slower to drill 8 inches into the concrete than it is to drill through the mudsill alone.

Of class, the large factor is cost:

  • A non-galvanized 5/8-in. ten 10-in. anchor bolt costs me almost $1.50, or $15 for 10.
  • X five/viii-in. 10 10-in. Potent-Bolt ii wedge anchors purchased online run about $30 (fastenersplus.com).
  • Ten 5/eight-in. x x-in. Titens run $60 online (also from FastenersPlus).

Given this cost, what works best for us are 5/8-inch bandage-in-place anchor bolts placed at 48 inches on-eye for our crawlspace walls. For garage walls, nosotros use Strong-Commodities two wedge anchors. The reason for the difference is that we frame our garage walls on the flooring and then drop them into place with the forklift. Trying to go them onto a bandage-in-place anchor bolt is a huge hassle when we can oversize our hole only 1/16 inch.

If I built merely on slab, I would switch entirely to wedge anchors. Using them would allow us to sheathe all walls earlier standing them up, and notwithstanding exist able to perfectly country them on the foundation before installing the anchors. That would save u.s. a huge corporeality of ladder work.