Division B
Acceptable Solutions

Part 5 — Environmental Separation

(See Appendix A.)  (See Part 10)

[Rev. 2, B.C. Reg. 73/2008.]

Section 5.6. Precipitation

5.6.1. Protection from Precipitation

5.6.1.1. Required Protection from Precipitation
(See Appendix A.)

1) [ . . . ] Where a building component or assembly is exposed to precipitation, the component or assembly shallI

a)minimize ingress of precipitation into the component or assembly,

b)prevent ingress of precipitation into interior space, and

c)be designed to drain any accumulated water to the exterior.

2) Deleted.

5.6.1.2. Protective Material and Component Properties

1) Except as provided in Sentence (2), where western cedar shakes or shingles are installed to provide the required protection from precipitation,I

a)the shakes shall be not less than No. 1 or Handsplit grade, and

b)the shingles shall be not less than No. 2 grade.

2) Where western cedar shakes or shingles are installed as undercoursing to provide the required protection from precipitation on vertical assemblies, they shall be not less than No. 3 grade.I

3) Except as provided in Sentence (4), where eastern white cedar shingles are installed to provide the required protection from precipitation, they shall be not less than B (clear) grade.I

4) Where eastern white cedar shingles are installed as undercoursing to provide the required protection from precipitation on vertical assemblies, they shall be not less than C grade.I

5.6.1.3. Installation of Protective Materials

1) Where a material applied to a sloped or horizontal assembly is installed to provide required protection from precipitation and its installation is covered in the scope of one of the standards listed below, installation shall conform to the requirements of the respective standard:I

a)CAN/CGSB-37.51-M, “Application for Hot-Applied Rubberized Asphalt for Roofing and Waterproofing”,

b)CGSB 37-GP-55M, “Application of Sheet Applied Flexible Polyvinyl Chloride Roofing Membrane”,

c)CAN3-A123.51-M, “Asphalt Shingle Application on Roof Slopes 1:3 and Steeper”, or

d)CAN3-A123.52-M, “Asphalt Shingle Application on Roof Slopes 1:6 to Less Than 1:3”.

2) Where masonry applied to vertical assemblies is installed to provide required protection from precipitation, installation shall conform to the requirements of CSA A371, “Masonry Construction for Buildings”.I

3) Where protective materials applied to assemblies are installed to provide the required protection from precipitation, the materials shall be installed to shed precipitation, minimize its entry into the assembly, prevent its penetration through the assembly and drain any accumulated water to the exterior. [See Appendix A.]I

4) Flashings, drips, or overhangs shall be incorporated to deflect accumulated water from the building face where there are changes in planes of walls and roofs, changes in cladding material, or window or door heads or sills. [See Appendix A.]

5.6.2. [ . . . ] Drainage, Accumulation and Disposal

5.6.2.1. [ . . . ] Drainage
(See Appendix A.)

1) [ . . . ] Materials, components, assemblies, joints in materials, junctions between components and junctions between assemblies exposed to precipitation shall beI

a)designed to shed precipitation, and

b)drained to direct precipitation to the exterior.

2) Deleted.

5.6.2.2. Accumulation and Disposal

1) Where water, snow or ice can accumulate on a building, provision shall be made to minimize the likelihood of hazardous conditions arising from such accumulation.I

2) Where precipitation can accumulate on sloped or horizontal assemblies, provision shall be made for drainage conforming with the relevant provincial or territorial regulations or municipal bylaws or, in the absence of such regulations or bylaws, with Article 2.4.10.4. of Division B of the National Plumbing Code of Canada 2005.I

3) Where downspouts are provided and are not connected to a sewer, provisions shall be made toI

a)divert the water from the building, and

b)prevent soil erosion.

4) Junctions between vertical assemblies, and sloped or horizontal assemblies, shall be designed and constructed to minimize the flow of water from the sloped or horizontal assembly onto the vertical assembly.I

5) Where a roof or balcony is entirely enclosed by parapet walls, a sufficient number of overflow outlets shall be installed in such parapet walls to drain the roof or balcony in the event that any rainwater conductors become obstructed. [See Appendix A.]I