BCAB #1905

February 16, 2023

Re:  Basement Interior Protection of Insulated Concrete Forms

Project Description:

The subject building is a house, three storeys in building height, with the lower storey being a “walk out basement”. The basement interior will be unfinished.

The portions of the basement exterior walls that are below grade are constructed of insulated concrete forms (ICF). It is proposed the foam plastic face of the ICF on the interior of the building be left exposed and unprotected.

The basement is connected to the main floor by an internal stairway and also has an exterior door.

Applicable Code requirements: (BCBC 2018)
9.10.17.10. Protection of Foamed Plastics
(See Note A-3.1.4.2.)
1) Except as provided in Sentences (2) and (3), foamed plastics that form part of a wall or ceiling assembly shall be protected from adjacent space in the building, other than adjacent concealed spaces within attic or roof spaces, crawl spaces, wall assemblies and ceiling assemblies

a) by one of the interior finishes described in Subsections 9.29.4. to 9.29.9.,
b) provided the building does not contain a Group C major occupancy, by sheet metal that
i) is mechanically fastened to the supporting assembly independent of the insulation,
ii) is not less than 0.38 mm thick, and
iii) has a melting point not less than 650°C, or
c) by any thermal barrier that meets the requirements of Sentence 3.1.5.15.(2).
(See Note A-3.1.4.2.(1)(c).)

Decision being appealed: (local authority’s position)

The local authority contends the ICF forms exposed to the interior of the basement must be protected as required by Sentence 9.10.17.10.(1). The local authority does not consider a 2.4 m high basement to be an exception for protection identified in Sentence 9.10.17.10.(1).

Appellant's position:

The appellant considers the basement as undeveloped and unoccupied, similar to a crawlspace that would not require the interior of the perimeter ICF walls to be protected. Adding a required protection substrate would establish the area as a finished space and would require additional measures to comply with the applicable electrical code.

Appeal Board decision #1905:

It is the determination of the Board that the exposed ICF foamed plastic must be protected from the interior space of the basement by those materials described in Sentence 9.10.17.10.(1).

Reason for decision:

Sentence 9.10.17.10.(1) requires foamed plastics be protected from adjacent spaces in the building, other than adjacent concealed spaces within attic or roof spaces, crawl spaces, wall assemblies and ceiling assemblies.

The submitted drawings designate the subject space as an unfinished basement, and the Board does not consider it to be a crawl space as it is readily accessible by both an interior stair and an exterior door and may be occupied.

Lyle Kuhnert
Chair, Building Code Appeal Board