Comments on: Rim Joist Insulation – Insulating Options

By: Todd

Todd — Thu, 21 Mar 2013 20:53:07 +0000

A drop ceiling in most cases does NOT count. There are some fire rated drop ceilings but they are very expensive and heavy.

By: John Leite

John Leite — Thu, 21 Mar 2013 16:15:47 +0000

It makes sense. Would a drop ceiling be sufficient or does it have to be drywalled?

Thanks again.

By: Todd

Todd — Tue, 19 Mar 2013 21:47:30 +0000

John – You are absolutely correct. What you can’t see is the fact that I’m finishing the ceiling in that area with 1/2″ drywall, which prevents the foam from being exposed. The code provision does NOT require the fire rated covering to be in direct contact, it just has to keep the area from being exposed. Make sense?

By: John Leite

John Leite — Tue, 19 Mar 2013 18:44:27 +0000

I have a question concering the foam board you used. I went to the Johns Manville site and it specifically states: “Do not leave exposed. AP sheathing requires an interior finish of a minimum 1/2″ (13 mm) gypsum board or equivalent 15-minute fire barrier. It doesn’t look like you covered the foam board with anything. Are you at risk in the event of a fire or am I missing something?

Thanks.

John.

By: Todd

Todd — Sat, 23 Feb 2013 00:29:37 +0000

Just be sure the OSB is dry. Other than that…I’d leave it alone.

By: Taco Mike

Taco Mike — Fri, 22 Feb 2013 16:18:00 +0000

Hi Todd. Thanks for the informative article. I live in a townhouse where the builder had covered the oriented strand board rim joists with standard fiberglass batts. Also, recently, water was being soaked up by the OSB due to the perimeter of the front door needing to be resealed. This problem has been taken care of and the OSB has remained dry.

Needless to say, since this incident occurred, I now worry about moisture especially since I am planning to finish the basement. Is there any added benefit at all by using a water seal paint on the OSB before insulating with foam board, or is it best to keep it as is? Thanks.