Soundproofing of
Wood-frame buildings
Learning objectives
• Basic Acoustic Principles and Definitions
• Impact and Airborne sounds in light wood-frame buildings
• Means of soundproofing light wood-frame buildings
• The Do’s and Dont’s
SOUNDPROOFING SOLUTIONS for:
- Flooring
- Ceiling
- Wall
- Plumbing
Problematic situations
• New York: 30 condos (120 000 sq.ft.) to fix = + $2M
• Quebec: 50 condos (50 000 sq.ft.) to fix (on going) = $$$$
• Toronto: Hotel (100 000 sq.ft.) to fix = $500 000
Acoustic insulation is not an expense,but an investment!
Two types of noises
• STC (Sound Transmission Class)
Airborne noises
• IIC (Impact Insulation Class)
Impact noises
Airborne noises
Talking TV Radio Pets
Laboratory testing for airborne noises measurement index (STC)
Airborne noise measurement index
STC (Sound Transmission Class)
FSTC (Field Sound Transmission Class)
ASTC (Apparent Sound Transmission Class)
4 basic acoustic principles
• Mass (max. of 2 masses)
• Resilience & Decoupling (2 and more)
• Filling joist cavity (Phonic absorption)
• Sealing
– The importance of these principles in the design and implementation of a project
– All project collaborators; architects, engineers, general contractors and any worker on a construction site, must know these principles and implement them as precisely as possible
Impact noises
Falling objects Moving furniture Walking / Running
Laboratory testing for impact noises measurement index (IIC)
Waves propagation in different materials
Impact noise measurement index
IIC (Impact Insulation Class)
FIIC (Field Impact Insulation Class)
AIIC (Apparent Impact Insulation Class)
Sound level auditory perception
Sounds can have different intensities and tones
Tone depends on frequency:Low pitch sounds = low frequencyHigh pitch sounds = high frequency
Increasing sound level vs. change in auditory perception
Increasing sound level Auditory perception
1 to 2 dB Not perceptible
+3 dB Barely perceptible
+5 dB Audible difference
+10 dB Sensation is doubled
+20 dB Sensation is quadrupled
Influence of lateral transmission (flanking)on AIIC final result
• Flanking can negatively influence the result by 4 to 10 dB and + ...
• How to mitigate flanking in wood-frame buildings:
1. Acoustic treatment of interior walls in contact with the structure
(acoustic insulation + resilient channel)
2. Interruption of structures continuity (wood and concrete topping)
3. Decoupling the floor covering and concrete topping
4. Decoupling the gypsum wallboards (drywall) and flooring
5. Decoupling the baseboards and quarter rounds
Decoupling
Building structure vs performance
Concrete structure Light wood-frame structure
Building structure vs performance
Cross-laminated Timber structure
(CLT)
“Hambro” structure
Light wood-frame structure as performantas concrete structure?
• Most of the time: low FIIC 50
• Sometimes: high FIIC 50
• NOW: possible to achieve as high as FIIC 69
Typical assembly of a wood-frame structure
Assembly description:
• Engineered flooring
• Acoustic membrane
• 1 ½’’ Concrete topping
• Resilient material
• Boards (OSB or Plywood)
• I-joists or open web joists
• Acoustic insulation
• Resilient channels or acoustic suspensions
• Gypsum
STC (Sound Transmission Class)
• More predictable
• Tests performed in laboratory and on site
• 14 on site tests performed by an independant certifiedacoustician, variation of 53 to 63 dB (average 58)
Causes results variation:
• Quality in work execution
&
• Application of direct and indirect acoustic principles
IIC (Impact Insulation Class)
• More difficult to predict
• Greater variation in results for identical assemblies
• Compilation of on site testing by independent certified acoustician and AcoustiTECH, variation of 45 to 65 dB (average 59)
Causes of results variation:
• Quality in work execution
&
• Application of direct and
indirect acoustic principles
Typical assembly of a wood-frame structure
Assembly description:
• Engineered flooring• Acoustic membrane
• 1 ½’’ Concrete topping
• Resilient material
• Boards (OSB or Plywood)
• I-joists or open web joists
• Acoustic insulation
• Resilient channels or acoustic suspensions
• Gypsum
Engineered flooring
The choice of floor type influences the result
• The density and composition of the engineered flooring assembly can make a difference of 2 to 4 dB
Typical assembly of a wood-frame structure
Assembly description:
• Engineered flooring
• Acoustic membrane • 1 ½’’ Concrete topping
• Resilient material
• Boards (OSB or Plywood)
• I-joists or open web joists
• Acoustic insulation
• Resilient channels or acoustic suspensions
• Gypsum
Acoustic membrane
The choice of membrane influences the result
• For greater acoustic performance, membrane must be installed as close to the point of impact (difference of 2 to 5 dB)
(First decoupling)
• Two types of membrane installations:– Floating
– Glued-down
Typical assembly of a wood-frame structure
Assembly description:
• Engineered flooring
• Acoustic membrane
• 1 ½’’ Concrete topping• Resilient material
• Boards (OSB or Plywood)
• I-joists or open web joists
• Acoustic insulation
• Resilient channels or acoustic suspensions
• Gypsum
1 ½’’ Concrete topping
• The presence of a concrete topping allows to multiply the quantity of resilient materials layers in the assembly (first mass)
- A membrane on top and underneath…
• The concrete type (light or standard) has little influence on the final result, but the mass weight plays a major impact
Typical assembly of a wood-frame structure
Assembly description:
• Engineered flooring
• Acoustic membrane
• 1 ½’’ Concrete topping
• Resilient material• Boards (OSB or Plywood)
• I-joists or open web joists
• Acoustic insulation
• Resilient channels or acoustic suspensions
• Gypsum
Resilient material
• It is important to isolate the concrete topping from the structure (second decoupling)
• Must be adapted according to the maximized efficiency load of the resilient material (compression)
• NOTE: The membrane quality and the application method can make a difference of up to 10 dB
Typical assembly of a wood-frame structure
Assembly description:
• Engineered flooring
• Acoustic membrane
• 1 ½’’ Concrete topping
• Resilient material
• Boards (OSB or Plywood)• I-joists or open web joists
• Acoustic insulation
• Resilient channels or acoustic suspensions
• Gypsum
Wood boards
• Plywood or OSB (Oriented Strand Board)?
• OSB offers a slightly superior performance thanplywood (1 to 2 dB)
Typical assembly of a wood-frame structure
Assembly description:
• Engineered flooring
• Acoustic membrane
• 1 ½’’ Concrete topping
• Resilient material
• Boards (OSB or Plywood)
• I-joists or open web joists• Acoustic insulation
• Resilient channels or acoustic suspensions
• Gypsum
I-joists or open web joists
• « I » joists perform slightly better than open web joists (gain of
1 to 2 dB)
Typical assembly of a wood-frame structure
Assembly description:
• Engineered flooring
• Acoustic membrane
• 1 ½’’ Concrete topping
• Resilient material
• Boards (OSB or Plywood)
• I-joists or open web joists
• Acoustic insulation• Resilient channels or acoustic suspensions
• Gypsum
Acoustic insulation
• For a better acoustic performance, the void must be at least 60% filled (ideally to 100%)
• Each 2’’ of insulation added increases the result by 1 dB(max. 10 dB)
• 1 gypsum = compacted acoustic insulation (more than 2.5 lbs)
• 2 gypsums = non-compacted acoustic insulation
Typical assembly of a wood-frame structure
Assembly description:
• Engineered flooring
• Acoustic membrane
• 1 ½’’ Concrete topping
• Resilient material
• Boards (OSB or Plywood)
• I-joists or open web joists
• Acoustic insulation
• Resilient channels or acoustic suspensions• Gypsum
Resilient channels and acoustic suspensions
• The addition of resilient channels (R/C) every 16’’ c/c rather than steel or wood furs will improve the assembly performance between 6 to 10 dB
• It is best to install the R/C every 24’’c/c rather than every 16’’ c/c (less contact points and a gain of 1 to 2 dB)
• The distance between the R/C is determined by the weight of the selectedgypsum (never surcharge the R/C) Maximum of two 5/8’’ gypsums « X » type
• Acoustic suspensions, compared to resilient channels, increase the performance of the assembly by 5 to 9 dB• The installation of acoustic suspensions is
one of the key components to obtain a FIIC of 62 and more…
Typical assembly of a wood-frame structure
Assembly description:
• Engineered flooring
• Acoustic membrane
• 1 ½’’ Concrete topping
• Resilient material
• Boards (OSB or Plywood)
• I-joists or open web joists
• Acoustic insulation
• Resilient channels or acoustic suspensions
• Gypsum
Gypsum
• The apparent ceiling material becomes our second mass (one of
the acoustic basic principles)
• It is best to always maintain the integrity of this surface
• NOTE:– By doubling the gypsum boards, we improve the assembly performance
by 4 to 5 dB
– Two 5/8’’ boards (« X » type) are better than two 1/2’’ pannels (« X » type) (+2 dB)
– Two 5/8’’ boards are better than one 1/2’’ board and one 5/8’’ board
Sealing
• The partition wall must be as air-tight as possible– «Where air is flowing, the sound is too»
• Seal the mechanical ducts in the partition wall and ceiling (plumbing, ventilation, fire system, etc.)
• Preserve the integrity of the partition ceiling (pay attention to flush-
mounted lightning, sprinkler heads, ventilation ducts, etc.)
• Significantly influences overall result (+ 10 dB)
Evolution of floor covering
Carpet and Rug synthetic fiber natural fiber
Ceramic and stone ceramic marble granite natural stone
Hardwood floor solid parquet prefinished engineered
Resilient rubber cork linoleum vinyl leather
Floor covering FIIC (usual average) FIIC achievable
Engineered flooring ≈ FIIC 55 to 61 ≈ FIIC 65 to 69
Carpet ≈ FIIC 75 + ≈ FIIC 80
LVT (vinyl tiles) ≈ FIIC 54 + ≈ FIIC 66 to 69
Solid wood on plywood ≈ FIIC 54 to 58 ≈ FIIC 59 to 66
Ceramic ≈ FIIC 47 to 55 ≈ FIIC 57 to 62
Typical assembly of a light wood-frame structure
Acoustic performance
Health and environment
Life time and durability
Easy installation
Mechanical strength
Thermal value
LEED®
SELECTION CRITERIA FOR AN
ACOUSTIC MEMBRANE
There is no magic recipe:
Every detail is crucial
Acoustic insulation is not an expense,but an investment!