Ruling No. 08-23-1197 Application No. 2008-20
BUILDING CODE COMMISSION IN THE MATTER OF Subsection 24(1) of the Building Code Act, S.O. 1992, c. 23, as amended. AND IN THE MATTER OF Article 188.8.131.52. of the Regulation 403, as amended, (the 1997 Ontario Building Code). AND IN THE MATTER OF an application by Lou Bada, Foxstar Group Ltd., for resolution of dispute with Leo Grellette, Chief Building Official, City of Vaughan, to determine whether the asinstalled ceramic tile flooring, where the ceramic tile has been applied directly to the subfloor with a scratch coat adhesive mortar (thin-set method), on a subfloor of 15.5 mm softwood plywood conforming to CSA 0151 or 15 mm OSB subfloor conforming to CSA 0325 with a reduced joist spacing of 300 mm (12 in.) on centre below the tiled areas, sufficiently complies with Article 184.108.40.206. of the 1997 Ontario Building Code at 32 Emily Anna Street, Vaughan, Ontario. APPLICANT
Lou Bada Foxstar Group Ltd., Concord, ON
Leo Grellette Chief Building Official City of Vaughan
Tony Chow, Chair Leslie Morgan Alison Orr
DATE OF HEARING
July 24, 2008
DATE OF RULING
July 24, 2008
Lou Bada Foxstar Group Ltd. Concord, ON The Applicant Allan Larden Larden Muniak Consulting Inc., Toronto, ON Agent for the Applicant Leo Grellette Chief Building Official City of Vaughan The Respondent
Particulars of Dispute
The Applicant has applied for and received a building permit to construct a two storey detached dwelling, with a building area of 154 m² at 32 Emily Anna Street in Vaughan, Ontario. The construction in dispute involves the method used for the installation of the ceramic tile in the subject building. The floor areas where ceramic tile has been installed, have been constructed as follows: • • •
All floor joists supporting the subfloor beneath the ceramic tile were spaced at 12” on center The subfloor beneath the ceramic consisted of either 15.5 mm softwood plywood conforming to CSA 0151 or 15 mm OSB subfloor conforming to CSA 0325 Ceramic tile was applied directly to the subfloor with a scratch coat of adhesive (thin-set method)
Sentence 220.127.116.11.(1) of the 1997 Building Code provides a choice of assemblies to reinforce a floor assembly that supports ceramic tiles set on panel-type wood sheathing. The Applicant has proposed a compliance equivalency in accordance with Section 2.7. of the 1997 Code, which permits materials, systems and building designs other than those authorized under the Code as long as the level of performance is maintained or exceeded. The Applicant claims that the asinstalled assembly is equal to or better than the assemblies permitted in the Code. The Chief Building Official has refused to accept the proposed equivalency. As a result, the Applicant has applied to the Building Code Commission to resolve the issue of whether the as-constructed ceramic tile installation demonstrates sufficiency of compliance with the technical requirements of Sentence 18.104.22.168.(1)
Provisions of the Building Code in Dispute
22.214.171.124. Reinforcement for Panel-Type Wood Sheathing (1) Except as permitted in Article 126.96.36.199., when ceramic floor tiles are set on paneltype wood sheathing, one of the following assemblies for reinforcing the floor assembly shall be used: (a) 20 mm thick plywood or waferboard with all edges supported by at least 38 mm by 38 mm blocking with floor joists spaced not more than 400 mm o.c., with 6 mm underlay, (b) sheathing with a thickness that conforms to Table 188.8.131.52.A. or a rating that complies to Table 184.108.40.206.B. and has an underlay consisting of 15.9 mm plywood or waferboard with offsetting joints, with a 4 mm gap between the sheets, or (c) subfloor sheathing reinforced with close spaced 38 mm by 38 mm blocking at spacings at least half that of the floor joist spacing.
The Agent for the Applicant claimed that it is common practice in the residential construction industry to apply ceramic tile directly to subfloor sheathing, typically 15.9 mm or even 19 mm plywood or OSB is installed as the subfloor sheathing. He also explained that in these circumstances, the floor joist spacing is reduced to 300 mm (12 in.) when 15 mm OSB or plywood is used, and 400 mm (16 in.) floor joist spacing when 18.5 mm or 19 mm OSB or plywood is used. However, the Agent reported that the ceramic tile at 32 Emily Anna Street has been installed as follows: • • •
Ceramic tile was applied directly to the subfloor with a scratch coat of adhesive (thin-set method) Subfloor was 15 mm OSB sub-floor conforming to CSA 0325 or 15.5 mm or 15.5 mm softwood plywood conforming to CSA 0151 The joist spacing below all ceramic tile areas was 12 in. on center
The Agent explained that the thin-set tile installation method that has been used for the subject property does not include an underlay. Instead ceramic tiles are applied directly to the subfloor. In addition, the joists are spaced closer than what is required in the Code The Agent maintained that the various descriptions of floor assemblies that are acceptable for the installation of ceramic tile flooring outlined in the 1997 Building Code relate to providing and adequately stiff support for the tile without allowing excessive deflection. Therefore, the Agent argued, that if a structural analysis can demonstrate that the floor assembly used to support ceramic tile at the subject property will deflect no more than any of the assemblies prescribed by the Code, then equivalency to the requirements of the Code will have been achieved. Referring to a February 13, 2007 structural analysis report, prepared by Quaile Engineering Ltd., the Agent asserted that Quaile’s analysis concluded that that the strength and stiffness of the floor system installed at 32 Emily Anna Street, Vaughan, is equivalent to, or better than, the waferboard/underlay assembly described in the Code for ceramic tile installation. Therefore, on this basis, the Agent argued, that the subject as-constructed floor assembly demonstrates sufficiency of compliance with Article 220.127.116.11 of the 1997 Building Code.
The Respondent submitted that the subject ceramic tile installation, does not meet the prescriptive requirements of Sentence 18.104.22.168.(1) of the 1997 Building Code. The Respondent maintained that the Code provides for a choice of assemblies to reinforce a floor assembly that supports ceramic tiles set on panel-type wood sheathing. The Respondent submitted that the proposal by the Applicant does not meet the specific requirements of the 1997 Building Code as set out in Article 22.214.171.124.
Commission Ruling It is the Decision of the Building Code Commission that the as-installed ceramic tile flooring, where the ceramic tile has been applied directly to the subfloor with a scratch coat adhesive mortar (thin-set method), on a subfloor of 15.5 mm softwood plywood conforming to CSA 0151 or 15 mm OSB subfloor conforming to CSA 0325 with a reduced joist spacing of 300 mm (12 in.) on centre below the tiled areas, sufficiently complies with Article 126.96.36.199. of the 1997 Ontario Building Code at 32 Emily Anna Street, Vaughan, Ontario.
Clause 188.8.131.52.(1)(a) of the Building Code requires that the floor joists be spaced not more than 400 mm (16 in.) on centre. The structural design of the floor assembly supporting the ceramic tiles in this building was designed to have floor joists spaced to 400 mm (16 in). The Commission heard that the areas where ceramic tiles have been installed using a thin-set method, have a reduced floor joist spacing of 300 mm (12 in.) on centre.
The Commission was presented with evidence and testimony that Quaile Engineering Ltd., an independent third party and professional engineering consulting firm, compared and analyzed the structural performance of the subject floor assembly with that of the three prescribed options in the Building Code. The Quaile Engineering documentation, submitted as part of application, concluded that the subject floor assembly provides strength and stiffness that is equivalent to, or better than the floor assemblies prescribed by the Code for ceramic tile application.
Dated at Toronto this 24th day in the month of July in the year 2008 for application number 2008-20.
________________ Tony Chow, Chair
________________ Leslie Morgan
________________ Alison Orr