Structural attachments and substrate assessment · Lesson 2 of 4

Structural attachments and substrate assessment: materials, standards and design constraints

The IBC and SPRI path by edition, the wood properties that set withdrawal resistance, treated wood and fastener metals, and why masonry anchor capacity is product-specific data.

You will be able to: Name the code path and standards that govern roof-edge attachment by edition, explain how wood density, moisture, grain and fastener type change what a nailer holds, choose fastener metals for treated wood, and read a masonry anchor evaluation report.

14 min · 12 slides · 11 questions

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Slide 1 of 12

The code path by edition

In the 2012 IBC, section 1504.5 required metal edge securement on low-slope built-up, modified bitumen and single-ply roofs, except gutters, to be tested to RE-1, RE-2 and RE-3 of ES-1.

SPRI says nothing changed in 2015, and that in 2018 the test reference became ANSI/SPRI/FM 4435/ES-1.

Always name the IBC edition your jurisdiction adopted.

Sources

SPRI Wind Design Seminar: Edge Metal Systems, First Line of Defense Against Wind (2025) - SPRI

Videos for this lesson

What this video shows: An American Wood Council presentation of about an hour and a half on nailed, screwed and bolted connections, including withdrawal capacity, tabulated and calculated methods, and wood-to-steel and wood-to-concrete connections. It is based on the 2015 edition of the NDS, so check the provisions of the edition in force. Checked against the video's description.

Video: 2015 NDS Connections Primer by American Wood Council, on YouTube. Chosen from the video's published description.

Glossary

Specific gravity (G): A wood density index. The Wood Handbook withdrawal equations define it on ovendry weight and volume at 12 percent moisture content; the NDS uses ovendry weight and volume, so the two bases differ slightly and results mixing them are indicative.
Withdrawal resistance: How much axial pull a fastener can take before it comes out of the wood; it depends on wood density, fastener diameter and depth of penetration.
Maximum load versus design value: A maximum load is the highest load a short-time test reached; design values are reduced from it for variability, duration of load and safety.
Use Category: AWPA's class for treated wood by exposure, for example UC1 interior dry, UC3B above ground and UC4A ground contact.
Special inspection: Inspection of an installed anchor required by an evaluation report under IBC sections 1704 and 1705, checking items such as anchor type, embedment, spacing and edge distance.