Fire rating

Originally Posted By: mpearson
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This is a picture of an attic of a new construction townhome I did today. Does the roof sheathing need drywall attached to it, that I so often see. I am not sure of the terminology or if it is required here? Also there was a gap at the top but I could not see through. Does this need draft blocking?

Mike Pearson
Lighthouse Building Inspections[img] (Small).JPG[/img]

Originally Posted By: rcloyd
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The link to your pic is not working.

Russell G. Cloyd
Intra-Spec Home Inspections
& Code Consulting, LLC

Originally Posted By: psisler
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In any firewall installation there can be no draft. The fire blocking must be total for it to work the way it is intended. If there is an air gap/pocket there can be backdraft and this defeats the purpose of the wall itself.


Originally Posted By: rking
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As an FPO in training, I must tell you that what you refer to is a “fire separation” not a “fire rating”.

As with anything else in this business be careful of your terminology.

A "fire separation" is there to keep the 'compartmentalization' of a unit intact to keep a fire or smoke contained in a given area for a set amount of time (dependant upon occupancy). The "fire rating" is the amount of time that a certain type of construction and/or materials will stay intact under fire conditions to uphold the "fire separation"

Information is available on the NFPA website, and your local building/fire department can probably give you information as well.

Something a lot of people do not know is that in most jurisdictions the Fire Department will inspect for Fire Code related building components for free upon request.

In my experience though, most people don't do this because "Then I will have to repair the deficincies" !!

I guess it comes down to the old "It won't happen to me" syndrome!

Muskoka Home Inspections
"Wisdom is the Anticipation of the Consequences"
Steering Committee Member At Large

Originally Posted By: Susan
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Hi Mike,

In my area, townhomes require a 2 hour separation between TH units. This is achieved by each unit having a 1 hour rating on each common wall. The drywall does go to the roof sheathing and if there is a gap, it must be sealed. This gap can be sealed with firecaulk (if reasonably small or packed mineral wool that is approved for this firewall).

Our area also requires what I (and the fire marshal in my jurisdiction) call break away clips. These are square type clips that are "L" shaped (when viewed from the side angle). These clips attach to metal channels and also to the adjacent stud. Kind of hard to describe but you may see them and wonder what they are. In common walls to another unit; they should be jogged in placement. These clips help hold the wall and contain fire should it occur.

Probably the most common problem I see in rough framing inspections where firewalls are present is the lack of proper sealing such as you saw with the gap. Also, the penetrations of the roof sheathing within the first 5 feet of another unit's roofline (such as a b vent) is prohibited here.

As mentioned in a previous post; check with the local building department or fire marshal. (Heck, if they're real nice; they may even show you what they look for in a real inspection!!) ![icon_smile.gif](upload://b6iczyK1ETUUqRUc4PAkX83GF2O.gif)

Take care,