Foam plastic trim around windows in 5-story building

[SH225]

This question could relate to many buildings, but let’s assume:

• 5-story apartment building
• 60 feet in height
• Type III wood construction
• Loadbearing 2-hour exterior walls with FRT plywood sheathing
• No tight fire separation distances
• 3-coat 7/8-inch cement plaster exterior wall finish

The face of the typical nail-fin window is 1-1/4 inch beyond the face of the sheathing, which leaves a gap of 3/8 inch to the wall finish. Over the plaster but under the finish coat is a picture frame of polystyrene foam trim 1 inch thick by 4 inches wide. Does 2015 IBC prohibit this foam trim in this situation?

Some of what I have found in 2015 IBC:

• 2601.1 says See Chapter 14 for requirements for exterior wall finish and trim.
• 1406.2 says Combustible exterior wall coverings shall comply with this section. Exception: Plastics complying with Chapter 26.
• 2603.5.2 requires a thermal barrier between foam plastic and the building interior, which in this case is the cement plaster.

 

[e hilton]

How is that different than eifs?

 

[SH225]

How is that different than eifs?

I think it probably isn’t. I reviewed some drawings for a project design team whose owner/builder client told them it violates code. I am trying to find something in the code that gives that indication - something we could prove or disprove.

 

[pstockert]

I think it probably isn’t. I reviewed some drawings for a project design team whose owner/builder client told them it violates code. I am trying to find something in the code that gives that indication - something we could prove or disprove.

If you are talking about Azek and similar PVCs, the latest ESR from the ICC only permits PVC (under conditions of use Section 5.3) to Type VB buildings under IBC 2018

ESR-1074 - ICC Evaluation Service, LLC (ICC-ES)

icc-es.org

I can't figure out why

 

[Paul Sweet]

I agree that the trim sounds like EIFS.

ESR 1074 par. 5.3.2 limits Azek architectural trim to 3 stories or 40 ft. and requires it to be backed by noncombustible construction on other construction types.