Roof Tie-Back Anchors for Wood Framing: One Beam or Two?

A roof tie-back on wood framing can fasten to one member instead of two. The Hardy Saddle Tie Back sits on a single beam, double truss or joist system and fastens with 1/4-inch SDS structural screws, so it needs half the structural framing members of a conventional system. There’s no drilling through the member and no roof membrane penetration, and the galvanized assembly supports 5,000 pounds.

If you’re an architect, structural engineer or framer on a wood building that needs Cal/OSHA roof tie-backs, this is the part of the roof that’s easy to overbuild.

How are roof tie-backs usually installed on wood framing?

Before the Hardy Tieback Anchor (HTB) existed, roof anchors were architect-specified, custom-built, and installed with bolts and plates. Hardy’s brochure compares two common assemblies:

Hardy’s own first product, the original HTB, was the first pre-manufactured, code-approved roof-mounted anchor device. It also needed two beams.

Two beams per anchor point adds up fast. At the code’s approximately 12-foot spacing, every anchor on the roof plan gets its own pair of structural members.

What does the single-beam saddle change?

The Hardy Tieback Saddle (HTBS), introduced in 2022, straddles one structural member. Installing the original HTB requires two beams. The HTBS needs one.

What that member has to be, per IAPMO UES ER-461:

• At least 5-1/4 inches wide. Saddles are available for wood beams from 5-1/4 to 12 inches wide.
• Sawn lumber or engineered lumber, with a minimum specific gravity of 0.50 for SDS screws.
• On a double truss, use the HTB-SDT. It’s 6-3/4 inches wide, and the minimum fastener length goes up to 3 inches.
• On a 5-1/4 inch member, you can add a solid 3/8-inch plywood filler fastened to the member, with 1/4 x 3 inch SDS screws on the filler side only.

The eyelet can face parallel or perpendicular to the framing.

Why do fewer framing members save money?

When one member does the job of two, each anchor point has one less beam for you to buy and for the crew to set. Multiply that by every anchor on the roof plan. That’s where the saddle’s savings on material and labor come from.

The other saving is where the work happens. Hardy recommends the framer installs the saddle on the ground, before the beams or trusses go up, because it’s much safer and faster. The detail sheet gives the same instruction: install HTB-S tie-backs while the beams are on the ground, before raising them into position.

Weight matters on a roof too. A 12-inch saddle weighs 65 lb. The Hardy Standard Tie Back runs 95 to 150 lb depending on height.

How many SDS screws does each saddle take?

Hardy Saddle Tie Back (single beam)

Use 1/4 x 3 inch SDS screws on the filler side when you’re on a 5-1/4 inch EWP beam.

Hardy Saddle Double Truss

The saddle comes with 5/16-inch holes for the screws. The detail sheet’s instruction is to use all of them.

Does a saddle tie-back penetrate the roof membrane?

No. The saddle installs with SDS structural screws into the framing. You don’t drill through the member, and you don’t penetrate the roof membrane, so the anchor doesn’t create a leak path. Compare that with the common bolted assembly in the table above, where the membrane gets penetrated by design.

How strong is a saddle on a single beam?

The strength comes from the ER-461 evaluation and Cal/OSHA’s own numbers:

• 5,000 lb peak load without permanent deformation, in the vertical and horizontal directions (ER-461 Section 3.1.2.1). That’s the load Title 8 §3291(f)(2)(C) requires in any direction.
• 3,100 lb ASD level strength, maximum, in the horizontal and vertical directions (ER-461 Section 3.1.2.2).
• Hot-dip galvanized in batches per ASTM A123. Cal/OSHA requires hot-dip galvanizing or equivalent corrosion resistance.
• Steel plates per ASTM A36 and extra-strong pipe per ASTM A53.

Two limits to put on your drawings. Each saddle is designed to support one worker only. And if the project uses fire-retardant-treated or preservative-treated lumber, contact Hardy or the lumber treater for corrosion and fastener recommendations.

What does the engineer of record still design?

The saddle replaces a custom anchor detail. The EOR still owns the structure around it:

• The support beam or truss. The detail sheet calls for a 5-1/4 inch minimum member designed by the EOR.
• Wood blocking and strapping on the framing next to the device, perpendicular to the framing, as specified by the structural design professional. The detail sheet shows a minimum of 3 bays on both sides of the device, minimum 48 inches.
• The tie-back locations, which ER-461 says a registered design professional determines.
• The calculations for the building official, prepared by a registered design professional where the jurisdiction requires it.

Hardy publishes calculations for the 12, 18 and 24 inch saddles on the resources page, so the EOR isn’t starting from zero.

Saddle tie-back installation checklist

1. EOR sizes the support member: 5-1/4 inch minimum width, 0.50 specific gravity for SDS screws.
2. Pick the saddle: HTB-S for a single beam, HTB-SDT for a double truss.
3. Confirm screw size and count from the fastening table, including 3-inch screws on any filler side.
4. Keep a copy of Hardy’s installation instructions on the job site the whole time you’re installing. ER-461 requires it.
5. Install the saddle on the beam or truss while it’s on the ground.
6. Fill every provided screw hole.
7. Install blocking and strapping per the EOR.
8. Schedule the post-installation proof load test before anyone ties off.

How Hardy helps

The Hardy Saddle Tie Back Anchor comes in 12, 18 and 24 inch sizes, with custom heights and widths available. Standard sizes are available through local suppliers: White Cap, Builders FirstSource and SouthernCarlson locations throughout California. It’s covered by IAPMO UES ER-461 and manufactured under an LA City Fabricators License.

You don’t need an EBM company to install it. Unless the project specification says otherwise, which is very rare, the contractor can install the anchors, and the framer on the project commonly does. ER-461 limits installation to qualified installers approved by Hardy, so confirm your installer with Hardy before the saddles go on. If you want a crew, Hardy installs through its partner Access Systems & Solutions. See installation.

Download the detail sheet, CAD file and calculations from resources, browse the full product line, or contact Hardy with your framing plan.