Agenda 04/23/2019 Item #11C (Sound Transmission Report)04/23/2019
EXECUTIVE SUMMARY
Recommendation to accept staff’s report on sound transmission and considerations regarding the
regulation of sound transmission for new attached single-family dwellings (townhouses).
OBJECTIVE: To present a report to the Board of County Commissioners (Board) that describes how
the Florida Building Code regulates sound transmission for commercial and residential buildings and
considerations regarding the regulation of sound transmission for new attached single-family dwellings
(townhouses).
CONSIDERATIONS:
Background
On March 26, 2019, Item 6A, Public Petition, the Board heard from Mr. Thomas Despard regarding noise
attenuation concerns with the Florida Building Code - Residential, as they relate to attached single-family
residential dwellings. In response, the Board directed the County Manager to have Growth Management
Department (GMD) staff bring back an item to explain the Florida Building Code’s noise attenuation
requirements and discuss any technical amendments that could be considered to mitigate sound
transmission between attached single-family residential dwellings.
Code Requirements
The Florida Building Code regulates sound transmission for multi-family condominiums and apartments.
The requirements are based on the sound transmission class (STC) scale. Simply put, the STC measures
the amount of sound that will be blocked from getting through to the other side of the wall and is
measured on a scale. Multi-family buildings are required to have a STC of not less than 50, an d not less
than 45 if field tested.
In contrast, attached single-family homes are not required to meet a STC. However, the Florida Building
Code does provide a special Appendix K - Sound Transmission that may be adopted by local
communities. Appendix K requires attached single-family homes meet an STC of 45.
Adopting Appendix K would require the amending Code of Laws and Ordinances Chapter 22 - Buildings
and Building Regulations through the public hearing process. Further, to conduct a technical amendme nt
to change the STC values noted within the Florida Building Code or to change the values established in
Appendix K would require consideration and review by the Florida Building Code Commission.
Public Vetting
Staff reached out to local building industry stakeholder groups and conducted research to determine
whether a technical amendment regarding sound transmission or adoption of Appendix K would be
appropriate and consistent with other jurisdictions in the area.
Mr. Despard’s concern was brought to the attention of the Developer Services Advisory Committee
(DSAC) by staff on August 2, 2017. DSAC discussed this matter with Mr. Despard and did not support a
local amendment to the Florida Building Code - Residential regarding sound transmission. The issue was
also presented to the Collier Building Industry Association (CBIA) in August 2017. Following a round
table discussion, CBIA did not recommend consideration of an amendment to the Florida Building Code -
Residential because it would not improve life safety but would add costs and construction time to a
project. CBIA indicated that a property owner can install upgrades to limit sound transmission at the time
of construction or during a remodeling project.
Research
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GMD Staff contacted 11 neighboring counties and cities from Sarasota to Marco Island to determine if
they had adopted Appendix K or a technical amendment of a similar nature. Of the eight communities that
responded, none had adopted Appendix K or a technical amendment. GMD staff also reque sted the
building industry members provide an approximate cost of construction to prevent noise transmission
from one unit to another on each shared wall between units of an attached single-family dwelling. One
response was received at an estimated cost of $10,000 per common wall to install materials to reduce
sound transmission.
Staff also conducted a review of residential building plans submitted to the county, illustrated in the
report (see the PowerPoint presentation), and established that some residential builders construct walls
within the Appendix K requirement, some far exceed the requirement, and some build very near to the
requirement. Therefore, staff recommends that no code changes nor the adoption of Appendix K is
necessary at this time.
FISCAL IMPACT: There is no fiscal impact associated with this action.
GROWTH MANAGEMENT IMPACT: There is no growth management impact associated with this
action.
LEGAL CONSIDERATIONS: This item has been reviewed by the County Attorney, is approved as to
form and legality, and requires majority vote for Board action. - JAK
RECOMMENDATION: To accept staff’s report on sound transmission for new attached single-family
dwellings (townhouses) and recognize that neither a technical amendment nor the adoption of Appendix
K is recommended at this time.
Prepared By: James French, Deputy Department Head, Growth Management Department, and
Richard Long, Director, Building Plan Review & Inspection Division
ATTACHMENT(S)
1. STC PowerPoint JCF (PPTX)
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COLLIER COUNTY
Board of County Commissioners
Item Number: 11.C
Doc ID: 8586
Item Summary: Recommendation to accept staff’s report on sound transmission and
considerations regarding the regulation of sound transmission for new attached single-family dwellings
(townhouses). (James French, Deputy Department Head, GMD)
Meeting Date: 04/23/2019
Prepared by:
Title: Operations Analyst – Growth Management Operations & Regulatory Management
Name: Judy Puig
04/11/2019 9:53 AM
Submitted by:
Title: Director - Building Plans Review & Inspections – Building Plan Review & Inspections
Name: Richard Long
04/11/2019 9:53 AM
Approved By:
Review:
Growth Management Department Judy Puig Level 1 Reviewer Completed 04/11/2019 9:53 AM
Growth Management Department Jeanne Marcella Department Head Review Completed 04/12/2019 7:48 AM
Growth Management Department James C French Deputy Department Head Review Completed 04/15/2019 6:17 PM
County Attorney's Office Jeffrey A. Klatzkow Level 3 County Attorney's Office Review Completed 04/16/2019 7:30 AM
Office of Management and Budget Valerie Fleming Level 3 OMB Gatekeeper Review Completed 04/16/2019 7:52 AM
Office of Management and Budget Laura Zautcke Additional Reviewer Completed 04/16/2019 9:45 AM
County Manager's Office Nick Casalanguida Level 4 County Manager Review Completed 04/16/2019 11:26 AM
Board of County Commissioners MaryJo Brock Meeting Pending 04/23/2019 9:00 AM
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Sound Tra nsmission in the
Florida Building Code
James French, Deputy Department Head, Growth Management Department
Richard Long, Director, Building Plan Review & Inspection Division
Board of County Commissioners Meeting –April 23, 2019
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Packet Pg. 267 Attachment: STC PowerPoint JCF (8586 : Sound transmissions for new multiple single-family dwellings
Apartment/CondoSound Tra nsmission Class Ratings
•Sound Transmission Class (STC ) is a number rating of how well a building partition attenuates airborne sound. It is used to rate interior partitions, ceilings and floors, doors, windows and exterior wall configurations
•STC provides a rough idea how much sound a wall might stop. STC is the most common sound reduction measurement in use. As common as this measurement is, it is limited and should not be totally relied upon for real world soundproofing expectations.
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Packet Pg. 268 Attachment: STC PowerPoint JCF (8586 : Sound transmissions for new multiple single-family dwellings
Apartment/CondoSound Requirements for Commercial Buildings
FBC-Building Code –12 Interior Environment
SECTION 1207 SOUND TRANSMISSION
1207.2 Air-borne sound.
Wa lls, partitions and floor/ceiling assemblies
separating dwelling units and sleeping units
from each other or from public or service
areas shall have a sound transmission class of
not less than 50, or not less than 45 if field
tested, for air-borne noise when tested in
accordance with ASTM E90.
Multi-family condo/apartment tenant separation wall
40 45 50 55 60 65 70
Sound Transmission Class Scale
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Packet Pg. 269 Attachment: STC PowerPoint JCF (8586 : Sound transmissions for new multiple single-family dwellings
Building Types in the FBC –Re sidential
•Single-Family: Detached one-and two-family dwellings
•Duplexes: Single-family attached
•To wnhouse: A single-family dwelling unit not exceeding three stories in height constructed in a group of two or more attached units with property lines separating such units in which each unit extends from foundation to roof and with a yard or public way on not less than two sides.
Separate Parcels, land beneath
home owned by owner
Duplex, single-family attached
To wnhouse, single-family attached
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Packet Pg. 270 Attachment: STC PowerPoint JCF (8586 : Sound transmissions for new multiple single-family dwellings
Available for Considerat ion: FBC -Re sidential
Sound Tra nsmission Appendix K
The provisions contained in this appendix are not mandatory unless
specifically referenced in the adopting ordinance.
FBC –Residential Code -APPENDIX K -SOUND
TRANSMISSION
AK102.1 General.
Air-borne sound insulation for wall and floor-ceiling
assemblies shall meet a sound transmission class
(STC) rating of 45 when tested in accordance with
ASTM E90.
Example Residential Builder meets 59.4 STC
40 45 50 55 60 65 70
Sound Transmission Class Scale
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Packet Pg. 271 Attachment: STC PowerPoint JCF (8586 : Sound transmissions for new multiple single-family dwellings
Re sidential Examples: Builder 1 –Mr. Despard
Sound Transmission Class Scale: 44.9
40 45 50 55 60 65 7 0
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Packet Pg. 272 Attachment: STC PowerPoint JCF (8586 : Sound transmissions for new multiple single-family dwellings
Re sidential Examples: Builder 1 -Vo lunta rily
Modified
Sound Transmission Class Scale: 64
40 45 50 55 60 65 7 0
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Packet Pg. 273 Attachment: STC PowerPoint JCF (8586 : Sound transmissions for new multiple single-family dwellings
Re sidential Examples: Builder 2 –Avera ge
Market Priced
Sound Transmission Class Scale: 52.4
40 45 50 55 60 65 7 0
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Packet Pg. 274 Attachment: STC PowerPoint JCF (8586 : Sound transmissions for new multiple single-family dwellings
Re sidential Examples –Builder 3 –Upper Market
Priced
Sound Transmission Class Scale: 59.4
40 45 50 55 60 65 7 0
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Packet Pg. 275 Attachment: STC PowerPoint JCF (8586 : Sound transmissions for new multiple single-family dwellings
Re sidential Examples –Builder 4 -Budget Based
Sound Transmission Class Scale: 44.9
40 45 50 55 60 65 7 0
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Re sidential Examples: Builder 5 -Budget Based
Sound Transmission Class Scale: 44
40 45 50 55 60 65 7 0
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Packet Pg. 277 Attachment: STC PowerPoint JCF (8586 : Sound transmissions for new multiple single-family dwellings
Community Feedback
•GMD Building Division and Contractor Licensing staff has received very limited
inquiries or complaints from homeowners about sound attenuation between
common walls in two-family or townhouse structures.
•Staff contacted 11 neighboring communities
•The following 8 communities have not considered adopting technical amendments
or the appendices
•City of Naples
•City of Marco
•City of Fort Myers
•City of Bonita Springs
•Lee County
•Manatee County
•Charlotte County
•Sarasota County
•The following 3 communities did not provide a response
•Hendry County
•Glades County
•Village of Estero
•Input received by one industry member affiliated with DSAC, CBIA, and familiar with
this type of construction, estimated the typical price per common wall to further
reduce sound transmission: $10,000
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Packet Pg. 278 Attachment: STC PowerPoint JCF (8586 : Sound transmissions for new multiple single-family dwellings
Industry Feedback and Staff
Re co mmendation
•DSAC –August 2, 2017
•Mr. Despard presented this item for consideration
•DSAC did not support the adoption of a local amendment
•CBIA –August 2017 Builders Roundtable
•CBIA did not support the adoption of a local amendment as
this is an available upgrade to consumers that would not
improve the life safety components of the Florida Building
Code but would add additional costs
•Staff
•Decision of the Board of County Commissioners
•Based off random sampling of different building plans
•Market based decision
•Further code restrictions may impact housing
affordability
•No other known jurisdictional authorities in the area
have adopted Appendix K
•Staff recommends that no action is taken, allowing this
to remain the consumers choice
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Packet Pg. 279 Attachment: STC PowerPoint JCF (8586 : Sound transmissions for new multiple single-family dwellings