Bay Area Residential Infill: 22 Issues Found

Summary: The Foundation Plan on S1.0 contains dowel notes specifying #6 rebar for the new footing reinforcement to be embedded into the existing footing. At the F3.4 footing location, the plan note reads 'DOWEL (6)#6 TOP & BOT FTG REBAR,' and at the F1.6 footing location, the plan note reads 'DOWEL (3)#6 TOP & BOT FTG REBAR.' Both notes reference Detail...

Why it matters: A #6 rebar has a cross-sectional area of 0.44 sq in compared to 0.20 sq in for a #4 bar — over twice the steel area. This discrepancy directly impacts the structural capacity of the new footing and its connection to the existing footing. If #4 bars are installed per the schedule but #6 bars were required by analysis, the footing and its...

Suggested next step: Please clarify the correct rebar bar size for the new footing reinforcement at footings F3.4 and F1.6 that is to be doweled into the existing footing. The plan dowel notes specify #6 bars while the Foundation Schedule specifies #4 bars. Please confirm the intended bar size, update the conflicting documents accordingly, and revise Detail 13/S2.0...

RFI draft: Please clarify the correct rebar bar size for the new footing reinforcement at footings F3.4 and F1.6 that is to be doweled into the existing footing. The plan dowel notes specify #6 bars while the Foundation Schedule specifies #4 bars. Please confirm the intended bar size, update the...

Summary: Reinforcing Steel Note 3 on the drawing specifies that all welded wire reinforcement shall conform to ASTM A185, which is the standard specification for plain (smooth) welded wire reinforcement. ACI 318-19 Section 20.2.1.1 requires that nonprestressed bars and wires shall be deformed, with plain bars or wires permitted only for use in spirals....

Why it matters: If WWR is procured to ASTM A185 (plain wire) and installed in structural applications such as slabs, walls, or foundations, it will not meet the bond and development length assumptions of ACI 318-19 for deformed reinforcement. This could result in inspection rejection and material replacement, causing significant construction delays and cost...

Suggested next step: Request the Structural Engineer of Record to revise Reinforcing Steel Note 3 to specify ASTM A1064 (deformed) welded wire reinforcement for all structural applications in compliance with ACI 318-19 Section 20.2.1.1, and clarify whether any plain WWR (per ASTM A185/A1064) is permitted solely for spiral reinforcement.

RFI draft: Request the Structural Engineer of Record to revise Reinforcing Steel Note 3 to specify ASTM A1064 (deformed) welded wire reinforcement for all structural applications in compliance with ACI 318-19 Section 20.2.1.1, and clarify whether any plain WWR (per ASTM A185/A1064) is permitted solely for...

Summary: The Design Criteria on the drawing labels the floor live load as 'Lr = 40 PSF'. ACI 318-19 Table 5.3.1 defines 'L' as live load (floor) and 'Lr' as roof live load, and assigns significantly different load factors to each. For example, in load combination Eq. 5.3.1b, L receives a factor of 1.6 while Lr receives only 0.5. By designating the 40...

Why it matters: If the floor live load of 40 PSF is applied using Lr load factors instead of L load factors, the critical gravity load combination (U = 1.2D + 1.6L + 0.5Lr) would be significantly unconservative—using a 0.5 factor instead of 1.6 for the primary floor live load. During plan review, this mislabeling could raise questions about whether the correct...

Suggested next step: Request the Structural Engineer of Record to correct the Design Criteria to designate the floor live load as 'L = 40 PSF' per ACI 318-19 Table 5.3.1, and confirm that the correct load factor of 1.6 for floor live load (L) was used in all applicable load combinations for the structural design.

RFI draft: Request the Structural Engineer of Record to correct the Design Criteria to designate the floor live load as 'L = 40 PSF' per ACI 318-19 Table 5.3.1, and confirm that the correct load factor of 1.6 for floor live load (L) was used in all applicable load combinations for the structural design.

Summary: The reinforcement schedule on sheet S0.2 lists minimum embedment lengths for standard end hooks at f'c=4500 PSI as 19' for #10 bars and 22' for #11 bars. These values are clearly erroneous: they are identical to the #7 (19') and #8 (22') bar values in the same column, and they represent a decrease from the #9 bar value of 25'. Development and...

Why it matters: If #10 or #11 hooked bars are used with f'c=4500 psi concrete anywhere on the project (or if concrete strengths are increased via future design changes), the tabulated values would result in insufficient hook anchorage. This could lead to a structural deficiency requiring rework, re-inspection, or an RFI during construction, causing delays and...

Suggested next step: Request the Structural Engineer of Record verify and correct the minimum embedment lengths for standard end hooks for #10 and #11 bars at f'c=4500 PSI. The currently tabulated values of 19' (#10) and 22' (#11) appear to be erroneous, as they are less than the #9 bar value (25') and match the #7 and #8 values respectively. Provide corrected...

RFI draft: Request the Structural Engineer of Record verify and correct the minimum embedment lengths for standard end hooks for #10 and #11 bars at f'c=4500 PSI. The currently tabulated values of 19' (#10) and 22' (#11) appear to be erroneous, as they are less than the #9 bar value (25') and match the #7...

Summary: The design criteria classify the building as Risk Category II with S1 = 0.965g and Seismic Design Category E. The foundation notes then state that the foundation system is designed using 1500 PSF bearing values based on CBC 2022 Table 1806.2 presumptive load-bearing values. For an SDC E structure, ASCE 7 requires a geotechnical investigation...

Why it matters: In this seismic category, foundation criteria must be tied to the required geotechnical evaluation rather than generic presumptive values. If the site-specific report produces different recommendations, the footings will require redesign; the sheet already states that footing elevations or footing designs can be altered by change order when...

Suggested next step: Provide the ASCE 7 Section 11.8 geotechnical investigation report for this Seismic Design Category E project, and revise Foundation Note 1 so the allowable bearing pressure and any required evaluation/mitigation for liquefaction, total and differential settlement, and surface displacement caused by faulting are based on the report's...

RFI draft: Provide the ASCE 7 Section 11.8 geotechnical investigation report for this Seismic Design Category E project, and revise Foundation Note 1 so the allowable bearing pressure and any required evaluation/mitigation for liquefaction, total and differential settlement, and surface displacement caused...

Summary: The sheet identifies the seismic force-resisting system as 'LIGHT - FRAME (WOOD) WALLS SHEATHED WITH WOOD STRUCTURAL PANELS' but also gives a blanket instruction that 'ALL WOOD-TO-WOOD NAILING SHALL BE PER CBC TABLE 2304.10.2.' ASCE 7-16 requires the members and fastenings in wood systems that resist seismic forces to conform to AWC NDS and AWC...

Why it matters: If seismic nailing is reviewed or installed from the CBC fastening table instead of the required AWC NDS/AWC SDPWS basis, wood shear wall and diaphragm fastening can require redesign during plan check, special inspection, or field inspection, creating costly revisions and installation changes in a Seismic Design Category E project.

Suggested next step: Please confirm that nailing for the wood seismic force-resisting system, including wood shear walls and diaphragms, is designed and detailed in accordance with AWC NDS and AWC SDPWS, and revise the general note that currently directs 'ALL WOOD-TO-WOOD NAILING' to CBC Table 2304.10.2 where it would apply to seismic-resisting elements.

RFI draft: Please confirm that nailing for the wood seismic force-resisting system, including wood shear walls and diaphragms, is designed and detailed in accordance with AWC NDS and AWC SDPWS, and revise the general note that currently directs 'ALL WOOD-TO-WOOD NAILING' to CBC Table 2304.10.2 where it...

Summary: The foundation plan lists two different slab assemblies in the same structural note block: “OPTION - 1” is a 4 in. slab and “OPTION - 2” is a 12 in. slab. ASCE 7 requires the actual weights of materials and constructions to be used for dead load. Leaving two materially different slab thicknesses as open options on the structural drawings does...

Why it matters: A 4 in. slab and a 12 in. slab create substantially different permanent loads. If the permitted structural documents do not fix which slab governs, review, field installation, and any later structural verification can be delayed or require redesign after the option is selected.

Suggested next step: Revise the structural drawings to identify the single slab option to be built at this location, or provide revised structural calculations/details that explicitly show both options have been designed and clearly state the governing dead load basis.

RFI draft: Revise the structural drawings to identify the single slab option to be built at this location, or provide revised structural calculations/details that explicitly show both options have been designed and clearly state the governing dead load basis.

Summary: On the Foundation Plan (S1.0), shear wall segments SW2 with lengths 4'-0' and 5'-0' are tagged with holdown H1, and segments SW2 with lengths 3'-9' and 3'-4' are tagged with holdown H3. On the Floor Framing Plan (S1.1), all corresponding SW2 shear wall segments are tagged with holdown H2. Per the Hold Down Schedule on S1.0, H1 is HDU5-SDS2.5...

Why it matters: The capacity disparity is particularly concerning at the SW2 3'-9' and 3'-4' segments, where H3 (6970 lbs) is shown at the foundation level but H2 (4565 lbs) is shown at the floor framing level—a roughly 35% reduction. If the floor-level holdown capacity is inadequate, the continuous overturning load path for the shear wall may be compromised...

Suggested next step: Request the structural engineer of record clarify the correct holdown designation at each level (foundation and floor framing) for all SW2 shear wall segments. Specifically confirm whether H1/H3 at the foundation and H2 at the floor framing is intentional or a drafting error, and if intentional, provide a note on the drawings explaining the...

RFI draft: Request the structural engineer of record clarify the correct holdown designation at each level (foundation and floor framing) for all SW2 shear wall segments. Specifically confirm whether H1/H3 at the foundation and H2 at the floor framing is intentional or a drafting error, and if intentional,...

Summary: S1.1 contains a tie strap schedule where mark A is specified as 'SIMPSON CS14,' and S1.1 also directs the contractor to 'REFER TO 3 & 4/S2.3 FOR HEADER DETAIL.' On S2.3, detail 4 'TYP STRAP @HEADER DETAILS' instead calls for a 'SIMPSON CS16 STRAP.' These sheets therefore give two different strap products for the header opening strap condition.

Why it matters: The strap designation affects connection capacity and the approved load path at framed openings. Leaving both requirements in the set can lead to the wrong hardware being purchased, installed, or inspected.

Suggested next step: Please confirm whether the header strap at the S2.3 opening conditions is to be Simpson CS14 per the S1.1 tie strap schedule or Simpson CS16 per S2.3 detail 4, and revise the drawings so one strap designation governs.

RFI draft: Please confirm whether the header strap at the S2.3 opening conditions is to be Simpson CS14 per the S1.1 tie strap schedule or Simpson CS16 per S2.3 detail 4, and revise the drawings so one strap designation governs.

Summary: The Foundation Plan (S1.0) specifies dowels as '(6)#6 TOP & BOT FTG REBAR' at the F3.4 footing location and '(3)#6 TOP & BOT FTG REBAR' at the F1.6 footing location, both referencing Detail 13/S2.0. However, the Foundation Schedule on S1.0 lists F3.4 with '(6)#4 TOP & BOT CONT DISTRIBUTED REINF' and F1.6 with '(3)#4 TOP & BOT CONT.' Detail 13...

Why it matters: This discrepancy directly affects the structural capacity of the new-to-existing footing connection. Using #6 bars instead of #4 significantly increases cross-sectional area (0.44 sq.in. vs 0.20 sq.in. per bar), which would alter the required adhesive anchor embedment capacity, affect bar spacing within the footing width, and change the...

Suggested next step: Request the structural engineer clarify the correct bar size for the footing reinforcement at F3.4 and F1.6 where new footings connect to existing footings. Specifically, confirm whether the bars should be #6 as shown in the Foundation Plan dowel notes or #4 as listed in the Foundation Schedule, and update all affected documents accordingly.

RFI draft: Request the structural engineer clarify the correct bar size for the footing reinforcement at F3.4 and F1.6 where new footings connect to existing footings. Specifically, confirm whether the bars should be #6 as shown in the Foundation Plan dowel notes or #4 as listed in the Foundation Schedule,...

Summary: The drawings give two different strap types for the same over-opening/header strap application. The 'TIE STRAP SCHEDULE' specifies mark A as 'SIMPSON CS14' with '36\' MIN EXTENSION BEYOND OPENING,' while detail 4 'TYP STRAP @HEADER DETAILS' shows 'SIMPSON CS16 STRAP W/10d NAILS, UNO.' with '36\' MIN' on each side of the opening. These sheets...

Why it matters: CS14 and CS16 do not represent the same connector capacity. If the wrong strap is installed, the opening load path may not match the engineer's intent, and permitting/field inspection can be delayed because the schedule and the detail call for different hardware.

Suggested next step: Please confirm whether opening/header straps are to be Simpson CS14 per the Tie Strap Schedule or Simpson CS16 per detail 4, and revise the schedule/detail so the strap type and fastening requirements are consistent.

RFI draft: Please confirm whether opening/header straps are to be Simpson CS14 per the Tie Strap Schedule or Simpson CS16 per detail 4, and revise the schedule/detail so the strap type and fastening requirements are consistent.

Summary: The Roof Framing Plan labels multiple 6X6 perimeter members as '6X6 DF#2' (Douglas Fir No. 2). However, the Timber specification on S0.1 explicitly requires 6X beams to be Douglas Fir No. 1. Additionally, the drawing's own legend defines posts as 'GRADE DF#1, UNO.' Whether these 6X6 members serve as beams or posts, Douglas Fir No. 2 contradicts...

Why it matters: Using a lower lumber grade (No. 2 vs. No. 1) reduces the allowable bending, shear, and compression design values for the member. In a seismic design category E project with significant lateral loads, undersized timber grades at roof framing perimeter members could compromise gravity load capacity and overall structural performance. This...

Suggested next step: Request the Structural Engineer of Record to confirm the required grade for the 6X6 members shown on the Roof Framing Plan. The specification requires Douglas Fir No. 1 for 6X beams, and the legend specifies DF#1 for posts. Please clarify whether the plan callout of '6X6 DF#2' is an error and should be revised to '6X6 DF#1,' or if engineering...

RFI draft: Request the Structural Engineer of Record to confirm the required grade for the 6X6 members shown on the Roof Framing Plan. The specification requires Douglas Fir No. 1 for 6X beams, and the legend specifies DF#1 for posts. Please clarify whether the plan callout of '6X6 DF#2' is an error and...

Summary: The floor framing plan calls out a new beam along grid B as '(N)6X8 DF#2' (Douglas Fir No. 2). However, the timber grade schedule on the Design Criteria & General Notes sheet specifies that all 6X beams shall be Douglas Fir No. 1. A No. 2 grade has lower allowable bending and other stress values compared to No. 1, so the beam as labeled may not...

Why it matters: If the beam was designed using No. 1 grade allowable stresses but constructed with No. 2 grade lumber, the member could be overstressed under design loads. This affects the structural adequacy of the floor framing at this location and could be flagged during plan review or field inspection.

Suggested next step: Request the structural engineer confirm whether the (N)6X8 beam along grid B should be Douglas Fir No. 1 per the specification timber schedule, or if No. 2 is intentional and the design has been verified for that lower grade.

RFI draft: Request the structural engineer confirm whether the (N)6X8 beam along grid B should be Douglas Fir No. 1 per the specification timber schedule, or if No. 2 is intentional and the design has been verified for that lower grade.

Summary: The drawing's typical sill plate anchorage detail allows 'REDWOOD OR PRESSURE TREATED LUMBER PLATE' in a condition explicitly identified as 'TYPICAL SILL PLATE ANCHORAGE TO CONCRETE.' The specification requires wood used in contact with concrete to 'BE TREATED WITH AN APPROVED PRESERVATIVE TREATMENT.' Allowing redwood as an alternative...

Why it matters: If this typical detail is followed with redwood instead of preservative-treated lumber, the sill plate at the concrete interface would not meet the specified durability requirement. That can create review and field inspection issues and may lead to noncompliant material being installed at multiple foundation wall locations.

Suggested next step: Please revise Detail 2 so the sill plate at concrete contact is preservative-treated lumber only, or issue a specification revision if redwood is intended to be acceptable in this condition.

RFI draft: Please revise Detail 2 so the sill plate at concrete contact is preservative-treated lumber only, or issue a specification revision if redwood is intended to be acceptable in this condition.

Summary: This sheet calls out 'FIELD NAILING @12\' OC' and 'WALL SHEATHING NAILS @ 6\' OC.' The specification states that 'THE FASTENER SPACING OF THE SHEATHING FOR WOOD SHEAR WALLS, SHEAR PANELS AND DIAPHRAGM IS SPECIFIED AT 4 INCHES OR LESS ON CENTER.' These callouts exceed the specified maximum spacing.

Why it matters: Because the specification ties this sheathing fastening to the 'SEISMIC FORCE-RESISTING SYSTEM' and mandates 'SPECIAL INSPECTION,' 6' and 12' o.c. callouts can create permitting and inspection discrepancies if left uncorrected.

Suggested next step: Please confirm whether the sheathing nailing on this sheet must be revised to 4' o.c. maximum, or whether the special inspection/specification note must be corrected so the required spacing is consistent.

RFI draft: Please confirm whether the sheathing nailing on this sheet must be revised to 4' o.c. maximum, or whether the special inspection/specification note must be corrected so the required spacing is consistent.