Thread: Garage/ House separation

I inspected a home today that had a breezeway between it and the garage. The garage ceiling was unfinished and the garage trusses carried across the breezeway into the attic of the home (finished ceiling in the breezeway). There was a plywood separation wall at the exterior of the home with a 30" hole sawed into it. Is this situation requisite of a proper firewall? Or, since the 2 buildings have 6' of separation between their exterior walls is it ok? Fire could lap across the ceiling into the attic so i'm going to call it out but wanted to hear thoughts

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Sounds like it was okay ...
[quote=Luc V. L.;162827]There was a plywood separation wall at the exterior of the home ... /[quote]

... until someone did this:

... with a 30" hole sawed into it.

If it is as you describe, properly patching that hole up should put it back as it was originally, and as it should still be.

They could use 1/2" gypsum board to cover one side of the plywood, that would make it better than out of plywood.

Since when is plywood OK for a fire separation wall? That's new to me.

Originally Posted by Benjamin Thompson

Since when is plywood OK for a fire separation wall? That's new to me.

Originally Posted by Jerry Peck

If it is as you describe, properly patching that hole up should put it back as it was originally, and as it should still be.

Many places allowed 1/2" plywood, the thinking was that it could just as well have been an exterior wall separating the two - which may well have had T-1-11 siding on the wall, i.e., "plywood".

If it was approved for use at the time of construction, it is still approved to be left in place on that house today, but not if it is removed and then replaced, in which case it would need to be gypsum board if done today.

Which is why I said:

They could use 1/2" gypsum board to cover one side of the plywood, that would make it better than out of plywood.

I.e., make it like it is allowed "today" and it would make it better than plywood.

Some places actually required Type X gypsum board, and if damaged it would need to be repaired with Type X gypsum board, however, if removed and replaced, it would only need to be 1/2" drywall if done today.

Obviously the hole is problematic but wrt the plywood, the IRC 2003 (R309.2) says:

The garage shall be separated from the residence and its attic area by not less than 1/2 " gypsum board applied to the garage side.Garages beneath habitable rooms shall be separated from all habitable rooms above by not less than 5/8 " Type X gypsum board or equivalent.Where the separation is a floor to ceiling assembly , the structure supporting the separation shall also be protected by not less than 1/2" gypsum board or equivalent.

I'd guess that first sentence would imply that since there is a roof connection, a proper firewall should be installed. Aka: plywood not ok.

Anyone disagree?

Originally Posted by Luc V. L.

a proper firewall should be installed.

The IRC is NOT referencing a "firewall". The IRC is referencing a "separation wall". There is a big difference.

Then you need to apply the code at the time of construction for things which existed at the time of construction.

You would, as I pointed out, apply today's code (i.e., the IRC) when it is removed and replaced.

If the wall is 20 feet long and 5 feet high with a 30" hole in it ... REPAIR the hole.

If the wall is 10 feet long and 3 feet high with a 30" hole in it ... you probably would need to cover the wall with gypsum board as the hole would be large as compared to the wall area.

Jerry,
Thanks for the verbiage correction.

Though this is a digression from the original question... not quite sure how to decipher when it's appropriate to recommend patching the hole with plywood or properly creating separation with gypsum, tape, mud, etc. Big difference in the size of the job involved, particularly because there is no way to get full sheets of rock up there through the trusses so they'd have to puzzle piece it together and mud all those seams to get it proper.

The wall was about 15' wide and 4' tall. Ironically at the midpoint of your subjective recommendations. It's been that kind of day...

All breezeways connected to a home our a garage must have a 1 hour fire wall protecting the home . The ceiling of the breezeway must be 1 hour also. This goes for sheds and garages connected to homes.

Originally Posted by gene schafer

All breezeways connected to a home our a garage must have a 1 hour fire wall protecting the home . The ceiling of the breezeway must be 1 hour also. This goes for sheds and garages connected to homes.

"must have a 1 hour fire wall "

No they do not.

I should clarify: under the IRC and codes based on the IRC. There are a few jurisdictions which may still require a 'fire resistance rated wall' which is still not a full-blown "fire wall", and there may be some jurisdictions which actually require a full-blown "fire wall", but more likely they require a 'fire-resistance rated wall' and call it a "fire wall".

They require "separation", and 1/2" gypsum board is suitable for that use, and, in fact, is specified for that use by the IRC.

Originally Posted by Luc V. L.

Though this is a digression from the original question... not quite sure how to decipher when it's appropriate to recommend patching the hole with plywood or properly creating separation with gypsum, tape, mud, etc.

First, if plywood was allowed in your area "back then" (it was in some areas), then the next decision would be 'is the repair a substantial area as compared to the wall area', and if not, then plywood going back, or, patch with gypsum board.

The code does not address things like this, other than to say that it (technically) requires a permit, or at least asking if a permit is required.

If it was there legally (that is the key) then it is allowed to remain. A different question is: Should it be allowed to remain as it was/is? Remember, the code is a minimum document, code is not good/better/best practices.

If the walls are combustible, they are not fire walls.

The common truss span running from garage through breezeway and into residence, requires protection, and separation as per the specifications for same (truss/roof assembly) as does the overall roof assembly of the home require protection and separation, especially at exterior home wall.

The garage and home are not separated structures they are tied in with a common roofing superstructure (common truss spans) as you have described them via the breezeway. I would expect the electrification is similarly routed/connected, and an interconnection of an overall GEC system.

FRT plywood perhaps, not regular plywood and not OSB by itself/themselves; otherwise gyp board or plus gyp board, plaster, etc. Blocking and stopping, fire and drafts to the separation/home exterior wall, as well. Since assuming here this "breezeway" is not inter-conditioned, the home's exterior wall "hole" likely should be insulated and a barrier such as tyvek or similar should be in place and covered exterior to the breezeway side of the closure also, since the "breeze" will be blowing through the "breezeway" and under the common semi-exposed to the outdoors breezeway "attic" roof structure and along the house side wall. The exposed common span trusses from the unfinished garage/unseparated garage roof should be blocked and stopped at the garage wall to breezeway demarkation. I am surprised there is no protection of exposed common span trusses in the garage area (common through breezeway to house attic) I would have expected at least gyp board in the garage side and underside of the roof deck for at least a bit to the inside of the garage if there were common spans.

Not only IRC as locally ammended, or whichever applicable building code at the time of original construction or new addition as locally ammended, modification, etc., but property maintenance codes, zoning codes and fire regulations.

If the original approved plans called for a SPECIFIED fire resistive assembly or construction detail, (such as the multitude of same you can find at UL), and approval (zoning and building departments) was based upon those specified plans/specified details - then maintaining at equilivent or better is required. If your construction was better than regular "minimum code" there may have been a requirement to have done so, i.e. conditional approval.

Your local building, planning, and zoning departments would be your best resource.

... and even if the walls were fire rated, it would still be a single fire division, unless they separated the combustible roof. Such as a parapet wall. Wich in order to be considered a firewall must be 18" above the combustible roof.

Originally Posted by Steven Turetsky

... and even if the walls were fire rated, it would still be a single fire division, unless they separated the combustible roof. Such as a parapet wall. Wich in order to be considered a firewall must be 18" above the combustible roof.

... since this has turned into a discussion about "fire walls" and note "separation" walls, then an alternative to the parapet wall would be to protect the underside of the roof sheathing out for 4 feet to each (both) sides of the fire wall, which would itself need to meet one of the fire wall designs.

You need to call out the missing 1/2" drywall separation (per IRC and not a firewall) from house to garage. They are connected and one structure. Doesn't matter if it's a breezeway.

Originally Posted by Door Guy

You need to call out the missing 1/2" drywall separation (per IRC and not a firewall) from house to garage. They are connected and one structure. Doesn't matter if it's a breezeway.

I think someone has missed of the above discussion ...

How about a drywall ceiling in the garage? Seems the simplest solution.

Originally Posted by Jerry Peck

... since this has turned into a discussion about "fire walls" and note "separation" walls, then an alternative to the parapet wall would be to protect the underside of the roof sheathing out for 4 feet to each (both) sides of the fire wall, which would itself need to meet one of the fire wall designs.

Hi Jerry,

I addressed the firewall issue because that is what the first entry of this thread is addressing.

Would the 4' rule create a separate fire division? Although I know of what you mention, I am looking in SCOPES and don't see it.