Firecode Drywall Requirements

6/17/2020 at 6:38:34 AM

Hi there.

Type x fire resistance is normally required when separating two different dwellings, ie. Between basement apartment and home, between two semi-detached and wherever there is a source of heat. 5/8" is typically used. If you currently have 1/2" and it needs to be fire rated, you could add another 1/2" infront.

I hope this helps.

Marko Furlani

President & Ceeative Director

Urbanest Construction

416.738.2547

6/17/2020 at 9:56:17 AM

Thank you very much Marko. If I understood correctly, what you said is consistent with what I read online so far that it's required in between two attached dwellings. We have a detached house but the inspector asked us to install fire rated drywalls on the outside walls. Is that normal?

Thank you.

6/18/2020 at 12:32:46 AM

The main reason for requiring a fire resistance rating on an outside wall is if the limiting distance (distance from the outside wall to property line) is less than 1.2 m,

Possible other scenarios involving fire safety measures adjacent to the property line include:

exceeding allowable limits to percentage of unprotected openings (windows/doors) depending on the limiting distance,

restrictions involving vented soffits again where in close proximity to the property line,

if the fire response time is over 10 minutes (it results in a doubling of the allowable limiting distance) and lastly but not leastly

if an adjacent building does not have the required limiting distance - occasionally a home will end up getting built too close to the property line or a building will change use (use and occupancy classification) and require a greater limiting distance in which case the buildings are analyzed using a limiting distance measured to an imaginary line between the two buildings.

A fire resistance rating may be mandated by any of these scenarios.

Thankfully the Building Code is now a free download so any fool like me can quickly & easily find the answer.

Thanks for letting me put on my thinking cap for a few minutes.