Building Codes Argument For Dek-Blocks Example (1 viewing) (1) Guest
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TOPIC: Building Codes Argument For Dek-Blocks Example
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Building Codes Argument For Dek-Blocks Example 5 Years, 9 Months ago
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The following is a response below to a letter about using Dek-Block for a floating deck in Upstate New York State. For those of you who do not know New York State well, the Finger Lakes region is between Rochester and Syracuse NY. Know as Central New York. And yes we get a lots of snow.
You can view my deck built with Dek-Block at www.hemmingsjones.com/decks
You can find this letter at www.flboa.com/html/code_update-32.html
June 11, 2003
RE: Exterior floor systems RCNYS Section 501.2
This is in response to your questions regarding the acceptability of a floating foundation deck system as proposed by DEKBRANDS, DEK-BLOCK, or other similar product in a residential application. Since your letter identifies multiple questions, I have answered them separately.
The first question is if a floating deck system, detached from a residence, is acceptable. You also identify that there are no headers or beams included in the system. First, it is our opinion that all decks constructed on the premises of a one- or two-family dwelling are regulated by the Residential Code of New York State (RCNYS). Furthermore, it is our opinion that this type of floating deck system can be acceptable.
RCNYS Section 202 defines a deck as "an exterior floor system supported on at least two opposing sides by an adjoining structure and/or posts, piers, or other independent supports." RCNYS Section R501.2 requires floor construction to be capable of accommodating all loads according to Section R301 and of transmitting the resulting loads to the supporting structural elements, including the foundation.
RCNYS Section 502.2.1 contains specific requirements for decks which are anchored to the primary structure, independently supported, or cantilevered.
The attachments provided with your letter contain evidence that the deck system is constructed of 2x6 dimension lumber. RCNYS section R301.1.2, entitled "Engineered design," allows the structural elements of an otherwise RCNYS compliant structure to comply with the BCNYS as follows:
When a building of otherwise conventional light-frame construction contains structural elements not conforming to this code, these elements shall be designed in accordance with accepted engineering practice. The extent of such design need only demonstrate compliance of nonconventional elements with other applicable provisions and shall be compatible with the performance of the conventional framed system. Engineered design in accordance with the Building Code of New York State is permitted for all buildings and structures, and parts thereof, included in the scope of this code.
The second question was with regard to the acceptability of a floating deck attached to a residence when the deck is not supported on footings below the frost line. In the attachments provided with your letter, it appears that the deck system is founded on DEK-BLOCK Brand Piers set at grade. It is our opinion that a deck is not required to be supported by footings below the frost line and that the type of pier identified in your letter is not prohibited by the RCNYS.
First, the RCNYS, Section R403.1, requires all exterior walls to be supported on continuous solid or fully grouted masonry or concrete footings, or wood foundations to frost. It appears that this situation does not involve the construction of exterior walls, thus not triggering a requirement for footings. Secondly, as described above, alternative foundation designs (engineered design) in accordance with the Building Code of New York State (BCNYS) can be constructed. The BCNYS, Section 1805.2.1, requires foundation walls, piers, and other permanent supports of buildings and structures larger than 400 square feet or 10 feet in height to extend below the frost line except if constructed on solid rock or otherwise protected from frost.
Lastly, in response to both questions asked, it is our opinion that the codes of New York State do not prohibit the use of any alternative materials, design and methods of construction and equipment. This is a provision of both the RCNYS and the BCNYS and is given below:
(RCNYS 104.11 & BCNYS 104.11) Alternative materials, design and methods of construction and equipment. The provisions of this code are not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved. An alternative material, design or method of construction shall be approved where the State Fire Prevention and Building Code Council finds that the proposed design is satisfactory and complies with the intent of the provisions of this code and that the material, method or work offered is, for the purpose intended, at least the equivalent of that prescribed in this code.
The first sentence allows the code enforcement official to approve alternative materials, design and methods of construction and equipment. The second sentence allows the Code Council to approve them, by means of the ICC ES reports (similar to the old Certificates of Acceptability). Thus, engineered design of an exterior floor system must be compatible with the design standards set forth in the codes of New York State and could be accepted by the code enforcement official.
Please be advised that this is not a product evaluation. Therefore, this letter is not intended to imply approval by our office but rather to provide guidance. This advisory opinion is rendered based upon the information provided. Administration and enforcement of the code are within the jurisdiction of the local authority.
If you have questions regarding this advisory, please call me at (518) 474-4073.
Sincerely,
Brian S. Tollisen, P.E.
Sr. Building Construction Engineer
Al03-126 Codes Division
Finger Lakes Building Officials Association, Inc.
3100 Atlantic Ave.
Penfield, NY 14526
info@flboa.com
Just a foot note about the Finger Lakes Building Officials Association and who they are:
FLBOA is comprised of over 200 county and municipal code enforcement officials from the Finger Lakes region of New York and beyond. Geographically we represent 7 counties. Our mission is to promote professionalism and consistency in the application and enforcement of building codes throughout our area. We achieve these goals through education, development, practice and enforcement of building codes utilizing our combined resources.
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