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Code question, wall board behind baseboard trim

Posted by wianno (My Page) on
Tue, Nov 25, 08 at 9:51

I need to do some work on an exterior wall, and am planning on pulling the baseboard trim and cutting the wallboard behind it to give me access to the bottom of the wall. By doing this I won't impact the finished part of the wall.

When I nail the trim back on, do I need replace the wallboard down to the floor plate to cover the wall cavity or can I just user spacers along the stud? I think I read somewhere that the wall cavities need to be sealed per fire code?


Follow-Up Postings:

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RE: Code question, wall board behind baseboard trim

regardless of code, leaving this area opened on an exterior wall is going make a difference in the comfort of the room. While I don't know how big your opening will be
the bigger the opening the more air infiltration.

In my house the floors were always cold, behind the baseboards was a 3" opening that was covered by the baseboards. when I sealed the openings and replaced the
baseboards I then caulked the top of the baseboard to the
wall, and the bottom of the baseboard to the floor.
It made quite a difference.

Although my case was more extreme than what you are proposing..seal your hole back up when you have finished with your work. put sheetrock back in place and caulk it once you have reattached it.

all that said..I believe it is a fire code issue and that you should check the fire safety portion of the code your area has adopted.

what type of work are you doing in your wall?

best of luck.


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RE: Code question, wall board behind baseboard trim

In our area, all wallboard has to be up and have a tape coat regardless of what is laid over it such as trims, panelings, tongue and groove ceilings,etc. You are not only going to want to replace behind the basboard, but tape coat it as well for the filtration reasons energy stated above.


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RE: Code question, wall board behind baseboard trim

I plan to remove the baseboard and wall so that I can get in there and insulate it. The air wips through along the entire lenght of the wall at the floor. I already insulated the box of the house under the floor, but the wind is still moving quite freely. I want to get into the wall to see what's up and solve the problem once and for all.


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RE: Code question, wall board behind baseboard trim

The only code required exterior wall fire protection I am aware of is that foam plastic insulation must be covered.


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RE: Code question, wall board behind baseboard trim

Wianno:

You are correct.

Stud spaces are required by Building Codes to be sealed at the ceiling and floor levels to cut off draft openings so as to form a fire barrier between stories.

For example, the 2000/2006 International Residential Code section R602.8 requires concealed spaces of stud cavities to be effectively fireblocked at ceiling and floor levels.

The simplest means to achieve this fireblocking is to install 1/2" drywall that is continuous and covers and terminates on the top and sole plates of every studded wall.

To do as you suggest...that is...to remove the drywall at the sole plate...and shim the base molding....COULD compromise the required fireblocking by allowing air infiltration into the stud cavities at the sole plate behind the base moldings....and thereby fan a fire that might erupt therein.

The proper approach in this case would be to replace and tape and finish the drywall behind the baseboards to maintain fireblocking of all wall stud cavities and only then install baseboard molding over the drywall.


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RE: Code question, wall board behind baseboard trim

Thought so. I'll just replace the wall board as required and tape it in. It will give me fire protection and help with whatever insulation I place along the floor plate. I suspect with the draft I get now, I am already exposed to problems with both!


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RE: Code question, wall board behind baseboard trim

You are both missing the point of code required fireblocking.

In platform framing, the interior drywall creates a concealed stud spaces and the sole plates, top plates, and floor sheathing, together, create the "fireblocking" required by the IRC "to form an effective fire barrier between stories and between top story and roof space."

Removing the lower portion of the drywall and covering the gap with baseboard effectively closes the concealed space, but even if it did not, the condition would not violate the IRC because it does not offer a path for fire to move to another floor. No draft is possible, in this case, if the stud cavity is sealed at the ceiling/floor above.


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RE: Code question, wall board behind baseboard trim

"Stud spaces are required by Building Codes to be sealed at the ceiling and floor levels to cut off draft openings so as to form a fire barrier between stories."

And the top plate and bottom plate are still sealing the stud cavity.

Drywall is routinely held up off the floor and the gap covered with baseboard to limit water damage from flooding.

The fire blocking is to prevent vertical spaces in excess of 10 feet high that could conduct flames from one floor to another.


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RE: Code question, wall board behind baseboard trim

Out here in the days when i was a framer, exterior walls were required to have midspan fire blocking on all stud spaces. Other areas were along stair stringers, hot water heater stands , drop ceilings that bumped exterior walls. attached garage walls were blocked as well as 5/8" fire code wallboard slab to ridge.

Now days mid span blocking is only required 3 spaces from the corners, 2 from openings on 8' walls. On taller walls, blocking is required at the 8' level even if it's a 9 or 10' wall.

Out here in the op's case, the upper edge of the drywall patch would be required to have a tape coat. The bottom edge fastened to the sole plate wouldn't as that's your block.


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RE: Code question, wall board behind baseboard trim

The only time any of this should be an issue in an exterior wall is if there is a soffit, dropped ceiling, or cove ceiling that joins the wall and ceiling cavities or if the framing system is of the balloon type.

Considering residential drywall on walls and ceilings to be an effective barrier to fire is a mistake because it is not normally rated for fire exposure and therefore will only stay intact a short time in a fire.

The intent of the fire-stopping code is to prevent hot gasses from traveling to another story (especially the attic) through narrow connecting spaces and igniting materials on that level and spreading the fire.

Fire blocking at mid wall height would allow a fire to penetrate the drywall and draft upward and/or downward if there is no fire blocking at the floor lines. If there is blocking at the floor lines, the mid height blocking would be unnecessary.

The '70 BOCA code had all the same requirements as the IRC except it required fire blocking at the top and bottom and the mid point of a stairway for some reason.


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RE: Code question, wall board behind baseboard trim

California codes differ from the irc, but is going to convert as of jan'09 to the irc. It is already recognizing the irc as of now. Ballon framing was ruled out here way on back in the 50's for residential when codes were brought into effect. Mid span blocking back in my day was fire blocking as it was on slab foundations with pt sill plates. Crawl space/basements were dealt with blocking inbetween the joisting with no rim boards that are typical these days. You still had a solid sill plate over the subfloor.


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RE: Code question, wall board behind baseboard trim

"Considering residential drywall on walls and ceilings to be an effective barrier to fire is a mistake because it is not normally rated for fire exposure and therefore will only stay intact a short time in a fire."

There is actually considerable data on the fore properties of even plain gypsum drywall.

The fiberglass added to type X is actually of marginal value in its fire rating.

Many places will accept 2 layers of 1/2 inch drywall as an acceptable fire stop between a garage and residence, even if type X is not used.


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RE: Code question, wall board behind baseboard trim

Gypsum board is highly resistant to fire but it has one great weakness: it contains 21% water by mass. This water is lost at 480 degrees F and the resulting shrinkage causes normal gypsum board to crack and fall apart.

Type X gypsum board is required by its ASTM standard to contain a fibrous glass mesh so it can stay together long enough to achieve a modest fire-resistance rating in a double-sided wall assembly.

Type C gypsum board is what is normally used today because it provides higher ratings and more efficient assemblies. In a fire it also loses all of its water and has a glass fiber mesh or loose fibers (there is no ASTM standard for it) but it also contains unexpanded vermiculite, muscovite, exfoliated zonolite, or other forms of mica which expand to fill the voids created by the departing water so far less shrinkage and cracking occurs. Therefore, it takes far longer for a Type C wall to fail and allow hot gasses and smoke to pass and thus it provides far greater protection in a wall assembly than its tested ratings indicates (a rating test stops when the non fire side reaches a certain temperature rather than at failure).

USG published a comparative test in Architectural Record where they took 13x12 inch, 5/8 inch thick pieces of Regular, Type X and Type C gypsum panels and suspended them over a heat of 1,800 degrees F, carrying a load of 12 lbs, 9 oz. The Regular panel failed in 12 minutes, the Type X panel failed in 58 minutes and the Type C panel did not fail during the two hour test even though the paper facing was destroyed on both sides.

The idea that a single layer of regular gypsum can contain a fire long enough to make much of a difference is unrealistic but that is not particularly relevant in a typical home where the absence of rated doors, door closers, and enclosed stairways allows a fire to rapidly and easily move from the room of ignition upon flashover which usually occurs before the fire resistance of the walls becomes an issue.


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RE: Code question, wall board behind baseboard trim

It is true that in multiple layer drywall assemblies the addition of glass fibers is less significant. Two layers of 1/2" regular drywall each side of a wall might achieve the same fire resistance as a single layer of 5/8" Type X each side, but I know of no test of such a wall.

But the purpose of fabricating boards with higher fire resistance is to achieve the highest fire resistance with the least material since cost matters to most of us. In this hypothetical example upgrading the two layers of 1/2" regular drywall to Type C (each side) would more than double the fire-resistance rating.

If you wish to provide the minimum fire protection and increase the sound isolation, the double layered regular board makes sense but that takes the issue beyond fire protection to a broader design discussion.

But as I mentioned before the fire-resistance of walls in a home is rarely significant because of the lack of fire compartmentalization. I often wonder why most of the codes seem so concerned about fire in a garage but don't require a rated door frame or door closer and will allow a basement to be open to the house. These requirements date back to when garages were generally left unfinished. It would be helpful if they would refer to required garage finishes as a smoke barrier or as structural fire protection and stop implying that it has a significant fire separation function. None of it means anything if the door is left ajar for the cat.


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RE: Code question, wall board behind baseboard trim

Wianno is still correct and the one who seems to be missing the point here is mughtyanvil.

Mightyanvil conveniently left out some language from the code text dealing with fireblocking that refutes his erroneously held position regarding fireblocking.

R602.8 of the 2000-200 IRC states:

"Fireblocking shall be provided to cut off all concealed draft openings (both vertical and horizontal) AND to form an effective fire barrier between stories..."

The purpose of fireblocking is not only to prevent fire from spreading between stories. The purpose of fireblocking is also to prevent the spread of fire within stories by eliminating draft openings.

Having drywall terminate on the top and sole plates is part of this required fireblocking of concealed draft openings horizontally between stud cavities which are usually present from holes laterally for pipes, cables, wires and so forth.

Not only is fireblocking required between stories, it is required to prevent drafts from spreading fire between adjacent stud cavities.

Part of this is accomplished by controlling drafts and combustion air to adjacent stud cavities so that fire cannot spread to other cavities or be fanned by combustion air provided at the base of framed walls.

What good is it in terms of fireblocking, for example, if receptacles and switches are placed in walls that are not covered by drywall and connect to open floor joists above also not covered in drywall, and the receptacle or switch ignites a fire?

It is no good at all.

Although top and bottom plates exist to prevent the flame from immediately penetrating the upper stories, the flame is not contained at all within the affected stud cavity unless drywall is installed.

The result is a fire that will quickly jump between stud cavities and to the floor assembly above.

Wooden blocking is therefore only a part of Code required fireblocking in structures.

Wall coverings to prevent the spread of flame and to cut off drafts is another.


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RE: Code question, wall board behind baseboard trim

If you simply read the next sentence of the section you quoted you will see a list of the locations where fireblocking is required and none of them mentions the blocking you describe.

You may reasonably recommend building a house with fire protection that exceeds the bare minimum required by the IRC but you should refrain from telling people such extra precautions are actually required by the IRC.


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RE: Code question, wall board behind baseboard trim

Mightyanvil still doesn't 'get it'.

The Code requires that walls framed with furring strips (as this poster wants to do) be properly firestopped.

R602.8

1. In concealed spacesof stud walls and partions, including furred spaces...

1.1 Vertically at ceiling and floor levels...

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Small wonder why we reject so many (ahem) "professional architects" plans in our office....

So few understand the Codes nor the standard to which they are supposed to design!


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RE: Code question, wall board behind baseboard trim

The OP said he wanted to use "spacers along the stud" which I took to mean a vertical spacer at each stud so there would be no furred space that would need blocking if the spacers occurred at each stud (or even up to 10 ft. apart) and it seems likely that he would need to do that in order to properly support the baseboard.

You seem keen to demonstrate superior knowledge about building codes. I suspect you could learn a great deal more about the meaning of their requirements if you paid more attention to the opinions of professionals with more experience and training than you rather than twisting the words, and therefore the meaning, of the code in order to win an argument.


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RE: Code question, wall board behind baseboard trim

"Mightyanvil still doesn't 'get it'.

The Code requires that walls framed with furring strips (as this poster wants to do) be properly firestopped.

R602.8

1. In concealed spacesof stud walls and partions, including furred spaces...

1.1 Vertically at ceiling and floor levels... "

I think manhatten42 does not get it.
The stud space IS closed by the bottom and top plates of the wall.

You can leave drywall off and meet the code.
You could drywall only the upper portion of a wall and meet the code, with nothing at the bottom of the upper drywall.

The blocking is top prevent fire from moving from floor to floor in a continuous chase (like old balloon framing had).


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RE: Code question, wall board behind baseboard trim

And about that ole balloon framing...

Is there a way that I could tell whether or not my house has balloon framing, without opening up walls?

I mean, could I answer my question (does my house have it or not) if I go up into the attic space, lie down across the top of the joists up there, inch my way to where the roof meets the joist, and peer down with a flashlight? If it had balloon framing, would I then 'see' all the way down to the basement?

Or is there a more logical method? :-)

Thanks in advance!


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RE: Code question, wall board behind baseboard trim

It might be easier to look in the basement to see if the studs sit on the sill beam instead of on the first floor sub floor.


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RE: Code question, wall board behind baseboard trim

"Is there a way that I could tell whether or not my house has balloon framing, without opening up walls?"

Balloon framing would only be in a very old house.

You can look down from the attic or up from the basement with a flashlight (you may also need a mirror).

If you see joists attached to studs, or sitting on a ledger strip (AKA 'ribbon') that is attached to the joist you very well may have a balloon framed structure.


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RE: Code question, wall board behind baseboard trim

Hi mightyanvil--thanks for your suggestion about the sill beam vs the first floor sub floor.
I am a total newbie--I'm asking about balloon framing because I started wondering if my house had it or not. So, which way indicates balloon framing--is it if the studs sit on the sill beam?

I'll try a Google image search for "sill beam", but now the question becomes will I know what the sill beam looks like when I see it? :-)

The basement is unfinished and I can see all of the joists and girders that are in the basement 'ceiling'. But I'm having trouble discerning whether the joists are attached to studs, or whether the studs are sitting on the sill beam or the first floor sub floor.

brickeyee, I'm living in a house that was built in either 1887 or 1888. Is that old enough for the builder to have chosen to use balloon framing?

Thanks!


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RE: Code question, wall board behind baseboard trim

It is most likely balloon framed. If so, the studs will rest on a 4x6 or 4x8 or 6x8, etc. wood member (sill) that sits on the top of the foundation wall. The joist will sit on it too but they might be notched so it sometimes looks like they are sitting on the wall. With more modern platform framing you wouldn't see any studs from the basement.


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RE: Code question, wall board behind baseboard trim

Here are examples of convential framing and balloon framing:

Here is a link that might be useful: balloon framing


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another diagram

Here's another, scroll down to the diagram:

Here is a link that might be useful: balloon diagram


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RE: Code question, wall board behind baseboard trim

Brickeye also wrongly stated:

"I think manhatten42 does not get it.
The stud space IS closed by the bottom and top plates of the wall.

You can leave drywall off and meet the code.
You could drywall only the upper portion of a wall and meet the code, with nothing at the bottom of the upper drywall.

The blocking is top prevent fire from moving from floor to floor in a continuous chase (like old balloon framing had). "

Nope.

No you cannot.

Which is why the Code specifically states in 602.8.1 that spaces that are 'furred' be firestopped at the top and bottom of the 'furred' spaces....

And why I AM a certified code enforcement officer and mightyanvil and brickeye are not.

(We reject these kinds of specious arguments all the time! lol)

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The Code requires that ALL 'furred' walls have a fireblock at their top and bottom....(as well as horizontally)...

And which practice the original poster decidely stated he would NOT do!

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The bottom line is that fireblocking MUST be maintained within framed walls regardless how it is maintained:

---by drywall
---wood blocks
---or other approved methods

And the bottom line remains that what the original poster suggested REMAINS a CODE VIOLATION. Period.


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RE: Code question, wall board behind baseboard trim

There was no furred space in the solution proposed by the OP so I don't understand your comments about code violations or why you feel it is necessary to make such childish insults.

I am not a bureaucrat; I design buildings for their owners for a living. That often requires me to provide a written code analysis. I've never had any aspect of a design successfully challenged by a building inspector in any of the nine states where I have practiced. That's not because I'm so smart; it's because when I am in doubt about an issue I call the organization that wrote it, not a building inspector.

I have been asked to provide architectural peer review for major buildings in my area and know that reviewing other people's work is a thankless, boring task. If you know so much about buildings, why don't you design them? Perhaps you just prefer criticizing the work of others.


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