Exposed joists - 1/2 Hr. rated assembly

[Cedazzi]

Working on a Type IIIB - R-2 residential 4 story building. Fully sprinklered
The corridors need 1/2 rated floor/ceiling assembly.

We want to maintain the historic look of the exposed joists in the corridor.
Is there a way to paint with intumescent to rated the structure 1/2 hour? We dont want to add a gyp layer underneath.

 

[classicT]

You may be able to find an EJ from an intumescent manufacturer, but I somewhat doubt it. What about wrapping the joist/floor in 5/8" Type X and then putting a veneer over to make it appear to be a larger, beam like joist.

 

[Paul Sweet]

There are some intumescent or ablative coatings for exposed steel, but I'm not sure if they are listed for wood. Also, they ain't cheap.

It would probably be easiest to add fake joists under a new rated ceiling if you have the headroom.

 

[ICE]

We want to maintain the historic look of the exposed joists in the corridor.

While not related to your question, I am curious as to what lumber will be used for a historic look of the exposed joist?

 

[north star]

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Cedazzi, ...if using a fire rated coating, be sure to check the specifications
before purchasing.......There are a lot of coatings \ paints out there that
say they are fire rated.

Intumescent Coatings - Fireproofing.US - UL Listed | fireproofing.us

Water Based Intumescent Paint. UL Certified up to 3 Hours Fire Rating. For use with Steel, Wood, Gypsum, Tin Ceilings.

fireproofing.us

Also, check the listings in U.L. and contact U.L. for guidance.

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