INTRODUCTION TO CONSTRUCTION TYPES Presenters Code Consultant Steven

INTRODUCTION TO CONSTRUCTION TYPES Presenters: Code Consultant: Steven R. Winkel, FAIA, PE The Preview Group, Inc. swinkel@preview-group. com Contractor: Scott Smith James E. Roberts-Obayashi Corp. Scott. wmith@jerocorp. com Architect: Anne Torney WRT | Solomon E. T. C. atorney@solomonetc-wrt. com

INTRODUCTION TO CONSTRUCTION TYPES For Infill Multi-Family Housing 1. The five basic construction types (as defined by the Building Code) …and why it’s not that simple 2. Typical configurations for San Francisco housing …and why there’s no such thing 3. Relative costs for different construction types …and why they’re not important 4. Case studies § Mid-rise vs. high-rise § Options for 5 stories of housing over non-residential base

1. The Five Basic Construction Types I II IV V Fire Resistance Allowable Area Most Least Allowable Height Allowable # of Stories Cost per Square Foot Fire-Resistive: Concrete or Steel Any Material with Fire Resistive Exterior Walls; Interior Any Material Wood: Heavy Timber Any material Rarely used for new construction

© John Wiley & Sons, from Building Code Illustrated

Showing allowable building heights (with and without sprinklers) number of stories (with sprinklers) and proportionate floor areas per story) © John Wiley & Sons, adapted from Building Code Illustrated

TYPICAL CONFIGURATIONS TYPE V Fulton Grove

TYPICAL CONFIGURATIONS TYPE V Del Carlo Court

TYPICAL CONFIGURATIONS TYPE V over TYPE I PODIUM Fine Arts Building

TYPICAL CONFIGURATIONS TYPE V over TYPE I PODIUM 8 TH AND HOWARD David Baker and Partners

TYPICAL CONFIGURATIONS TYPE II or Type III over TYPE I PODIUM 101 San Fernando

TYPICAL CONFIGURATIONS Type I Midrise Broadway Family Apartments

TYPICAL CONFIGURATIONS Type I Midrise PLAZA APARTMENTS LMS/ Paulett Taggart Architects

TYPICAL CONFIGURATIONS Type I High-rise International Hotel Herman Coliver Locus Architecture

RELATIVE CONSTRUCTION COSTS – Based on Construction Type CONSTRUCTION TYPE V: # OF RES. STORIES WOOD 4 MAX RESIDENTIAL FLOORS METAL (plywood deck) TYPE III: * WOOD RELATIVE COST / SF WHY 1. 00 1. 04 5 MAX + fire-treated lumber framing at exterior walls 1. 07 METAL (plywood deck) 1. 03 + metal TYPE II: METAL (metal deck) 5 MAX 1. 10 + metal deck w/ concrete topping TYPE I: MID-RISE (concrete) 8 MAX 1. 25 + concrete frame HIGH-RISE (concrete) UNLIMITED 1. 30 + fire safety features + 1% per floor over 9 GARAGE/UNFINISHE D T. I. SPACE GARAGE ON GRADE (multi-level) 0. 40 GARAGE ON GRADE (single level) 0. 50 GARAGE BELOW GRADE TYPE I: 0. 60 * Man lift and possibly tower crane needed for buildings over 60’. Cost per square foot varies. Relative costs courtesy of Scott Smith of the James E. Roberts-Obayashi Corporation most efficient + shoring, waterproofing

WHY YOU SHOULD IGNORE THE PREVIOUS SLIDE Relative construction costs are driven by type of construction AND… Site: Shape, size, topography, soils, fire finishing & construction access, zoning Unit Type: Flats (double or single loaded), townhomes, studios, family units, stacking, repetition Ownership vs. Rental Circulation Ratio of skin to interior area Size of project Parking: Yes or no, configuration, efficiency Foundation Systems Mechanical, Electrical and Plumbing Systems Finishes Et cetera…

CASE STUDY: MID-RISE vs HIGH RISE High-rise (403) Mid-rise Floor level (not “height”) at less than 75’ feet above lowest Fire Dept. access Defined as floor level at more than 75’ above lowest Fire Dept. access Sprinklers required for R Occupancy Sprinklers required No elevator lobbies in sprinklered < high-rise Elevator lobbies No command center Fire command center ≥ 4 stories, elevator on emergency power Elevator on standby power = generator, in 2 hour rated room (generator) or provide horizontal exit for accessible means of egress (1007) Fire alarm Voice/alarm No smoke control Smoke control Typ. stair shaft enclosures, 2 hour > 4 stories Smoke proof enclosure No standby power Standby power for fire command, fire pump (if any) Communication required for accessible means of egress Stairway communication No rescue air Rescue air replenishment system in SF

WHY 75’ FOR A MID-RISE? © John Wiley & Sons, from Building Code Illustrated

© John Wiley & Sons, from Building Code Illustrated

CASE STUDY: MID-RISE VS. HIGH-RISE OPTION 8 -STORY MID-RISE UNIT S S. F. RELATIVE COST/ S. F. RELATIV E COST RELATIVE COST/UNIT 66 97, 500 1. 25 $121, 875 8 & 13 -STORY HIGH-RISE 100 136, 000 1. 30 $176, 800 $1, 768 13 -STORY HIGH-RISE 132 152, 000 1. 31 $199, 120 $1, 508 Costs per S. F. increase… $1, 846 But costs per unit may decrease.

CASE STUDY: FIVE FLOORS OF HOUSING

CASE STUDY: FIVE FLOORS OF HOUSING SANSOME & BROADWAY

CASE STUDY: FIVE FLOORS OF HOUSING over NONRESIDENTIAL BASE SANSOME & BROADWAY

CASE STUDY: FIVE FLOORS OF HOUSING - OPTIONS OPTION A 5 stories Type II metal over 1 story Type I podium B 5 stories Type III metal over 1 story Type I podium C D 4 stories Type III wood over 1 story Type III concrete over 1 story Type I podium 5 stories Type III wood over 1 story Type I podium TOTAL # STORI ES # OF RELATIVE CONSTRUCTABILI UNITS COSTS TY NOTES Most? ? Fire-resistive construction throughout, including metal deck floors with Levelrock topping Could have plywood decking at floors 6 50 Avoids dense framing @ lowest wood level & associated mech. & elect. coordination issues Least? ? 2 -hour exterior walls w/ fire-treated lumber; dense framing @ lowest wood level, which can create utility coordination issues Option D appeared to be the option with the least cost for this particular project, but the answer will vary from project to project.