ASCE 7-22 Components and Cladding Wind Load Changes: What's Different from 7-16

In most cases, the ASCE 7-22 changes to components and cladding (C&C) wind loads change where you find a coefficient, not the pressure you end up with. The ASCE 7-22 Commentary states that most of the highest and lowest roof $G{C}_p$ values did not change from ASCE 7-16.^[1] Three changes do affect the result. $G{C}_p$ went up for gable roofs at 7° to 20° and for Zones 2 and 3 on hip roofs at 27° to 45°. The directionality factor $K_d$ shifts the pressure if a template moves it on only one side of the equation. And ASCE 7-22 adds a C&C check on the underside of elevated buildings that 7-16 never required.

The rest is reorganization, and some of it can trip you up. Chapter 30 went from seven Parts to five, and the numbering doesn't carry across in order: "Chapter 30, Part 4" meant the simplified pressure tables in 7-16 and means building appurtenances in 7-22. Both simplified table methods were deleted. The sloped gable and hip figures were redrawn with fewer zones, the overhang procedure moved into Section 30.7, and roof pavers got their first ASCE 7 design path in Section 30.12.

Not all jurisdictions have adopted ASCE 7-22. Verify the edition in force in your jurisdiction before applying these provisions.

ASCE 7-22 C&C Changes at a Glance

Only two of the ASCE 7-22 Chapter 30 changes below can move a pressure on a building you already know how to design: the roof $G{C}_p$ revisions, and $K_d$ if it isn't moved on both sides of the equation. The elevated-building check adds a new load. The rest change which method applies or where to find it. The rows follow the same order as the sections below.

Chapter 30 Part Numbers Shifted Between ASCE 7-16 and 7-22

ASCE 7-16 Chapter 30 had seven Parts; ASCE 7-22 has five. The two simplified pressure-table methods, 7-16 Part 2 (h ≤ 60 ft) and Part 4 (60 ft < h ≤ 160 ft), were deleted, and the remaining Parts moved up. Under 7-22, enclosed, partially enclosed, and partially open buildings use the analytical procedure in Part 1 (h ≤ 60 ft) or Part 2 (h > 60 ft).

Trace each 7-16 section to its 7-22 number:

Only Part 1 and Sections 30.1 through 30.3 still mean the same thing. "Chapter 30, Part 4" meant simplified tables for mid-rise buildings in 7-16 and means parapets and overhangs in 7-22; "Section 30.9" meant roof overhangs and now means attached canopies. A reference to a deleted section fails visibly. These resolve to real 7-22 sections, so nothing flags them. Check every Chapter 30 Part and section reference in specifications and templates before 7-22 C&C work goes out.

Two content changes come along with the renumbering. Parapets (7-16 Section 30.8, now 30.6) keep the same Load Case A and Load Case B, with $K_d$ now in the pressure equation. Attached canopies (7-16 Section 30.11, now 30.9) are no longer limited to h ≤ 60 ft, and 7-22 adds Figures 30.9-2A–B for taller buildings.

$K_d$ Moves Into Every ASCE 7-22 C&C Pressure Equation

ASCE 7-22 moves the wind directionality factor $K_d$ out of the velocity pressure equation and into the pressure equations, in Chapter 30 (C&C) just as in Chapter 27 (MWFRS). First, $K_d$ leaves velocity pressure:

Then it reappears in each C&C pressure equation. The swap is easiest to see in the most common case, enclosed and partially enclosed buildings with h ≤ 60 ft:

The other Chapter 30 procedures follow the same pattern:

In Eq. 30.4-1, $q=q_z$ for windward walls (varying with height); $q_i=q_h$ for enclosed and partially open buildings, and for negative internal pressure in partially enclosed buildings. For positive internal pressure in partially enclosed buildings, $q_i=q_z$ at the height of the highest relevant opening, with $q_i=q_h$ permitted as a conservative simplification.

$K_d$ = 0.85 for buildings (ASCE 7-22 Table 26.6-1), the same value as in 7-16. For a standard enclosed building the two editions give the same pressure: the $K_d$ that 7-16 built into $q_h$ is written into the 7-22 pressure equation instead. That holds only if a template makes both halves of the move.

What a half-migrated template produces. Take the corner-zone soffit panel from the worked example below ($q_h$ = 48.0 psf computed without $K_d$, Zone 3 $G{C}_p$ = −3.2, $G{C}_{pi}$ = +0.18):

Nothing flags either error. Both give a pressure that looks reasonable for a corner zone on a coastal building.

The other 7-22 load chapters shift their basis the same way, including the snow load provisions.

Gable and Hip Roof $G{C}_p$ Figures: Fewer Zones, a Few Higher Values

ASCE 7-22 Figures 30.3-2A through 30.3-2G replace the nine ASCE 7-16 figures, 30.3-2A through 30.3-2I, for gable and hip roofs with h ≤ 60 ft. Commentary C30.3.2 states: "Most of the highest and lowest $(G{C}_p)$ values have not changed except where zones have been merged or where the zones were modified to better fit the actual wind tunnel data."^[1] It names two exceptions where 7-22 pressures are greater: "gable roofs with a slope of 7 to 20 degrees, and Zones 2 and 3 on hip roofs with a slope of 27 to 45 degrees."^[1]

Trace each 7-16 roof figure to its 7-22 figure:

Three structural changes drive the map. The 7-16 sloped-roof sub-zones (2e, 2n, 2r, 3e, 3r) merged into Zones 1, 2, and 3. The two hip overhang figures, 7-16 Figures 30.3-2F and 30.3-2I, were deleted, and every overhang now goes through Section 30.7. And the printed slope equations on the 7-16 hip figure for 27° to 45° were replaced by interpolation between 7-22 Figure 30.3-2F (27°) and Figure 30.3-2G (45°) at the same effective wind area, with "Zones 2 and 3 on a 45-degree slope … interpolated to Zone 3 on a 27-degree slope."^[1]

Watch the hip figure letters. 7-16 Figure 30.3-2G (hip, 20° to 27°) is 7-22 Figure 30.3-2F, and 7-22 Figure 30.3-2G is the 45° hip figure. A template that still cites "Figure 30.3-2G" for a 24° hip roof reads the wrong graph.

Effective Wind Areas Below 10 ft²

The ASCE 7-22 roof graphs are flat below 10 ft², so the coefficient at 10 ft² applies to any smaller effective wind area. Commentary C30.3.2 explains that little wind tunnel data backed the 7-16 values below 10 ft², and that the Wind Load Subcommittee judged "with small EWAs, there is significant load that occurs between cladding elements, thus distributing the effects of the high localized pressures presented in ASCE 7-16."^[1] Some coefficients came down as a result.

The Commentary does leave a path for elements genuinely smaller than 10 ft², such as roof tile. You may extend the sloped portion of the graphed line down to the required area and read $G{C}_p$ there, "while considering any load-sharing reduction factors from relevant studies or testing."^[1] This is Commentary guidance, not a requirement of the provision.

Elevated Building Bottom Surfaces: New ASCE 7-22 C&C Requirements

ASCE 7-22 Section 30.3.2.1 (h ≤ 60 ft) and Section 30.4.2.1 (h > 60 ft) set C&C design requirements for the bottom horizontal surface of elevated buildings on columns, piers, or stilts. ASCE 7-16 has no equivalent provision. Large-scale wind tunnel testing (Kim et al. 2020,^[2] Abdelfatah et al. 2020^[3]) found bottom-surface $G{C}_p$ values similar in magnitude to roof values, and Commentary C30.3.2.1 notes that "field observations have shown substantial floor underside cladding loss due to wind."^[1]

Both provisions treat the underside as a roof surface, but they modify different inputs:

$h_B$ is the height of the bottom surface above grade. On sloping ground it is the largest height between the slope and the bottom of the building, and above a parking garage Commentary C30.4.2.1 measures it from the parking deck.

For h ≤ 60 ft the two heights do different jobs: $h_B$ sets how wide the high-coefficient bands are, and h sets the velocity pressure they multiply. Commentary C30.3.2.1 explains that the wind tunnel tests "determined $G{C}_p$ values for both the roof and the bottom horizontal surfaces based on the velocity pressure at mean roof height. That reference velocity pressure has been retained in these provisions."^[1] For h > 60 ft, the velocity pressure height matches the MWFRS provision for elevated-building bottom surfaces (ASCE 7-22 Section 27.3.1.1.3).

Worked Example: Bottom Surface of an Elevated Coastal Pavilion

Design parameters:

• Location: coastal North Carolina; Risk Category II
• Elevated single-story pavilion on piers, 100 ft × 80 ft in plan; least horizontal dimension = 80 ft
• $h_B$ = 10 ft (bottom-of-floor height above grade); $h$ = 22 ft (mean roof height)
• Gable roof at 6:12 (26.6°), so the 10% wall reduction in Figure 30.3-1 Note 5 (θ ≤ 10°) does not apply
• Exposure D, flat terrain ($K_{zt}$ = 1.0), sea level ($K_e$ = 1.0), V = 130 mph
• Enclosed building, $(G{C}_{pi})$ = ±0.18 (Table 26.13-1)
• Soffit panel with effective wind area = 10 ft², in the corner zone
• An enclosed 12 ft wide storage room sits below the floor

Scope: the bottom-surface check under ASCE 7-22 Section 30.3.2.1 only, not the roof, wall, or MWFRS loads (Section 27.3.1.1) on the building above.

Solving for:

Start with the velocity pressure at mean roof height, h = 22 ft:

Next are the zone dimensions, which is where $h_B$ comes in. Figure 30.3-1A lays out the soffit zones in multiples of $h_B$: a Zone 2 strip $0.6h_B$ wide along each edge, a Zone 1 strip $0.6h_B$ wide inside it, and L-shaped Zone 3 corners with $0.6h_B$ legs, $0.2h_B$ wide.

With the true mean roof height the same dimensions would be 0.6(22) = 13.2 ft and 0.2(22) = 4.4 ft. The $h_B$ substitution scales every soffit zone by 10/22 = 0.45.

Corner zone pressure. From Figure 30.3-2A at 10 ft² effective wind area, Zone 3 gives $G{C}_p$ = −3.2. Pairing it with positive internal pressure gives the largest magnitude, and on the bottom surface a negative result acts downward:

Next to the storage room walls, the Zone 4 requirement applies. $a_B$ = min(0.4 × 10, 12) = 4.0 ft, so the soffit within 4.0 ft of the room's walls takes the positive Zone 4 wall coefficient of +1.0 at 10 ft² (Figure 30.3-1), paired with negative internal pressure:

Commentary C30.3.2.1 explains that these positive coefficients "are meant to address wind pressure build-up caused by wind flow being restricted by the wall or enclosed area and are set equal to the pressure coefficients used for the soffits of overhangs."^[1]

Each soffit component must be designed for both the maximum positive and the maximum negative pressure at its location (Figure 30.3-2A Note 4). For a beach house on piers or any building over an open substructure in a 7-22 jurisdiction, this check covers the floor assembly. The roof and wall provisions don't.

Roof Overhang $G{C}_p$ Under ASCE 7-22 Section 30.7

ASCE 7-22 Section 30.7 covers roof overhangs on buildings of all heights and states the additive rule in the provision itself. The overhang $G{C}_p$ is the sum of its two surfaces:

$G{C}_{p,\text{overhang}}=G{C}_{p,\text{top surface}}+G{C}_{p,\text{bottom surface}}$

where the top-surface coefficient "is the same as the applicable roof surface's $G{C}_p$" and the bottom-surface coefficient "is the same as the adjacent wall's $G{C}_p$, adjusted for effective wind area." For h ≤ 60 ft both terms come from Figures 30.3-1 and 30.3-2A–G; for h > 60 ft, from the Part 2 roof and wall figures such as Figure 30.4-1. The one exception is a gable roof at θ ≤ 7° with h ≤ 60 ft, where Section 30.7 still lets you read the overhang $G{C}_p$ directly from Figure 30.3-2A. I read "adjusted for effective wind area" as taking the wall coefficient at the overhang element's effective wind area, not the wall's.

This replaces the ASCE 7-16 arrangement, where hip roofs had dedicated overhang figures (30.3-2F and 30.3-2I) and the gable figures carried their own overhang graphs. A 7-16 template that reads overhang $G{C}_p$ from one of those graphs has nothing to read in 7-22 outside Figure 30.3-2A.

The positive wall coefficient acts upward on the soffit and adds to the uplift on the top surface. Zones 4 and 5 share the same positive wall coefficient at every effective wind area, +1.0 at 10 ft² (Commentary Table C30.3-1), so it doesn't matter which wall zone sits below the overhang. Commentary C30.3.2 works an example, an edge-zone (Zone 3) overhang on a 27° hip roof at 10 ft²:^[1]

Here the wall term raises the uplift coefficient 50% above the roof value alone. On a low-slope roof it is smaller: Note 5 of Figure 30.3-1 reduces wall $G{C}_p$ by 10% when θ ≤ 10°, so the wall term at 10 ft² becomes +0.9.

The combined coefficient is the net load on the overhang deck and its framing. The soffit panel is a separate component. Figure 30.7-1 Note 3 sets the positive pressure on the soffit equal to the wall pressure, so soffit cladding and its attachments are designed for the adjacent wall pressure. The elevated-building provisions use the same values: Commentary C30.3.2.1 notes that the positive Zone 4 coefficients under an elevated floor "are set equal to the pressure coefficients used for the soffits of overhangs."^[1]

Roof Pavers: A First ASCE 7 Design Path in Section 30.12

ASCE 7-22 Section 30.12 gives the design net uplift pressure on roof pavers for buildings of any height with roof slopes ≤ 7°. ASCE 7-16 had no paver provision.

Two details set Equation 30.12-1 apart from the rest of Chapter 30. $C_{L_{net}}$ is defined as a net uplift coefficient, and the equation has no internal pressure term. And $q_h$ is evaluated at the mean height of the roof the pavers sit on, so pavers on the lower roof of a stepped building use that roof's height, not the building's.

Commentary C30.12 explains why pavers get their own provision. Gaps between pavers and the space beneath them let pressure equalize between the top and bottom surfaces, which "helps reduce the net uplift compared with the external pressure calculated for a roof."^[1] The highest uplifts still occur near roof edges and corners. Section 30.12 offers three ways to set $C_{L_{net}}$:

As published, Section 30.12 cited Figure 30.5-1 for Option (a); ASCE 7-22 Errata 2 corrects the reference to Figure 30.4-1.

Options (b) and (c) have to account for the five factors Commentary C30.12 lists: building and roof geometry; the ratio of gap width to pedestal height, $d_g/h_g$; interconnection of pavers by straps or other means, which spreads uplift over a larger area and more weight; dynamic effects that keep pavers from responding to short-duration gusts; and parapet height.

The choice matters most at corners. A 2 ft × 2 ft paver has a 4 ft² effective wind area, so Option (a) reads the 10 ft² value from Figure 30.3-2A: $G{C}_p$ = −3.2 in Zone 3. At this article's velocity pressure ($q_h$ = 48.0 psf, $K_d$ = 0.85), that is 48.0(0.85)(3.2) = 130.6 psf of net uplift. A 2 in. concrete paver at 150 pcf weighs 25 psf. A loose-laid paver resists uplift mainly with its own weight, so Option (a) asks a corner paver for about five times what it weighs before load factors, and 130.6/(0.9 × 25) = 5.8 times under 0.9D + 1.0W. A parapet 3 ft or taller sets Zone 3 negative values equal to Zone 2 (Figure 30.3-2A Note 5), which gives 48.0(0.85)(2.3) = 93.8 psf, or about 3.8 times. Credit for equalization under (b) or (c) is what closes that gap.

Transition Checklist

Work through these before your first ASCE 7-22 C&C submittal. Each one points back to its section above.

1. Part and section references. Check every Chapter 30 citation in specs and templates. Parts 2–5 and Sections 30.4–30.13 all point to different content in 7-22.
2. Deleted simplified methods. The 7-16 simplified pressure tables are gone. Work that relied on them moves to the Part 1 or Part 2 analytical procedure.
3. $K_d$ on both sides. The target is $q_h$ without $K_d$ and $K_d$ = 0.85 in the pressure equation. Miss either half and pressures come out about 18% high or 15% low.
4. Zone labels. Zones 2e, 2n, 2r, 3e, and 3r are gone from the sloped roof figures. Map reports and specs to Zones 1, 2, and 3.
5. Hip roof figures. Enter Figures 30.3-2E through 30.3-2G by slope band, and interpolate between 2F and 2G above 27°. Retire any template that still uses the 7-16 slope equations.
6. Effective wind areas below 10 ft². Use the 10 ft² coefficient, or extend the sloped line per Commentary C30.3.2 for tile-size elements.
7. Elevated building bottom surface. A new check with no 7-16 counterpart. For h ≤ 60 ft, $h_B$ sets zone dimensions and h sets velocity pressure.
8. Overhang procedure. Section 30.7 governs: roof zone $G{C}_p$ plus the adjacent positive wall coefficient.

The Bottom Line

Check specifications and templates for Chapter 30 Part and section references before running any 7-22 C&C numbers. Move $K_d$ out of $q_h$ and into every pressure equation in the same edit, and take roof coefficients from the 7-22 figures by zone and slope band rather than translating 7-16 sub-zones. Recheck fastener and connection design on gable roofs at 7° to 20° and hip roofs at 27° to 45°, where the Commentary reports higher pressures. On any elevated building, add the underside check under Section 30.3.2.1 or 30.4.2.1; only Section 30.3.2.1 exempts floors less than 2 ft above grade.

Related Resources

• ASCE 7-22 MWFRS Wind Load Changes: the Chapter 26–28 side of the same transition, including the $K_d$ move and the elevated-building procedure in Section 27.3.1.1
• ASCE 7-22 Snow Load Changes: the same shift in load basis in the Chapter 7 snow provisions, from ground snow maps to drift loads
• Rain Load Calculation per ASCE 7: static head, hydraulic head, ponding, and the SDSL changes in 7-22
• Replace your load spreadsheets: why edition-specific load development belongs in a tool that cites its own work

If you read any of this differently or have run into it applied another way on a real project, reach out at support@prose-eng.com. I'm a practicing engineer, not an infallible one.