Sound Insulayment (Part 2)

Howard Grundland here – I am an independent flooring specialist, certified nationally for inspections and consulting. The series of articles I am writing are with the intent to improve the quality of both flooring installation and selection. It is my desire to mitigate installation failures which are, at the least, a pain. Tile, natural stone, wood, laminate and vinyl will be covered in my series of articles, and I am always available to help if you have questions. Click here for Part 1

1. What is the source of the specifications?
2. Do the established specifications meet the Building Code?
3. Are the established specifications realistically achieved?
4. Has the selected product for Sound Insulation had its documentation qualified and reviewed?
5. Does the product selected meet both Building Code and the specifications established?
6. What is the legal liability in the product selection and specification process?
7. Who is liable?
8. Where does the responsibility for selection of Sound Insulation material start and where does it end?

Specifications for Sound Insulation can be established to meet the minimum requirement per Florida Building Code (FBC) or International Building Code (IBC). FBC/IBC specifications require an IIC (Impact Insulation Classification) and STC (Sound Transmission Classification) of 50 (see Part 1). Specifications of Sound Insulayment may also be established seeking a higher level of Insulayment. Typically, the project owner, with the participation of the architect, would specify the requirements. It becomes the responsibility of the General Contractor and/or the Installation Contractor to seek out and provide a product to meet the established requirement. It would be important to note that the establishment of an IIC/STC of 50 does not allow for the application of field test results. Should that be the case, the specification should call for an FIIC/FSTC (see Part 1).

There is no established relationship in testing results between a field test and a laboratory test. Some might use logic to imply the following: FBC calls for a 50IIC/50STC in laboratory or a 45FIIC/45FSTC in the field; therefore, the variation between a laboratory test and field test is approximately 10% (50- 45=5=10 %-+). Using that logic, the conjecture could be made that if we take the result of a field test and add 10%, we would come to the equivalent as if the product has been laboratory tested. Therefore, a product with a field test of 45FIIC/FSTC would logically have a laboratory result of 49-50 IIC/STC (45×10%=4.5+45=49.5). This is not so! Scientifically within the world of acoustical engineering, there is no calculated correlation or equivalency between laboratory testing and field testing.

Therefore, should specifications be established calling for an IIC/STC of 50, the results should come from an approved laboratory test. If the specifications are established allowing for a field test, they should read FIIC/FSTC. Please note that some building departments will only accept field tests when supplied from testing on site at the actual property.

Establishing specifications for IIC over 55 will not be realistically achieved when seeking laboratory testing. This statement requires further qualification. Typically, ceilings in living spaces for apartments of modern day mid-rise or high-rise buildings are concrete. Under certain conditions, a drop ceiling (plenum) will appear, usually in the bathroom and possibly kitchen areas. To date, the highest laboratory test results for Sound Insulayment materials reaching a maximum of 55II in an apartment without a ceiling assembly system in the living space would reflect a testing specimen reflected in the laboratory test:

• conducted on an eight-inch (8″) or six-inch (6″) concrete slab, without any additional substrate on the concrete;
• conducted without any ceiling assembly system. Look up and see concrete;
• conducted using thin set or modified thin set to install tiles;
• conducted after setting materials have cured per ASTM E492 & E90 and tiles have been grouted;
• conducted with tile covering an area meeting required testing dimensions per ASTM E492 & E90;
• conducted with one (1) layer of selected sound Insulayment material.

When qualifying a Sound Insulayment product, laboratory testing should be reviewed. Look at the testing specimen. It is critical. When accepting field test results, read the documents carefully. Confirm the slab thickness along with the other specimen parameters.

Part 3 will continue to address these questions. If you missed Part 1 and would like a copy, please send your request to

Howard Grundland
Flooring Specialist Consultant/Forensic Inspections FCITS, CSI, WFCA, ICR

Howard has worked in the flooring industry more than twenty-five years.  His background includes both commercial and residential applications.  He has worked with all surfaces of flooring including carpet, vinyl, wood, tile, natural stone, laminates and a variety of concrete applications. In 2002 he began focusing on the installation process and the appropriateness of product selection. Howard has worked with importers, distributors, dealers of tile, natural stone, hardwood and laminates.   He has an extensive background of installation practices, installation materials, product familiarity as well as flooring sound insulation and water proofing. He received his certification from the Flooring Consultants and Inspectors Training Services (FCITS) and is nationally certified as a flooring consultant and inspector of hard surfaces and commercial applications. Crossville, Laticrete, Jamo, Tec Industries, Bonsal, Congoleum, Armstrong, Tarkett, Custom Building Products, Ardex, Schluter, Noble, Proflex, Dodge Regupol, Schluter, Bruce Hardwoods and Wilson Art have been part of his educational background. Howard has developed various educational programs for flooring which have been presented to architects, developers, general contractors and installation companies.  He has also offered training and consulting for various building departments in the southeast Florida region. Howard’s Education includes Temple University, The New York Institute of Technology, and The Kushi Institute.