Soundproofing of Wood-frame buildings · Influence of lateral transmission (flanking)on AIIC final...

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!