Buelligan
Registered User
2009 IRC
I have a contractor who wants to amend his plans to eliminate the footing between units. He says "what do I need that for, it only holds drywall?" First of all it will be supporting two one hour walls with 5/8" Type x on each side three stories tall! (UL Design U305) He wants to pour ONE 4" thick slab across ALL 6 units without the separating foundations.
R302.2 Townhouses. Each townhouse shall be considered a separate building and shall be separated by fire-resistance-rated wall assemblies meeting the requirements of Section R302.1 for exterior walls.
My interpretation of the above section requires a perimeter foundation for "each" unit including the "common" fire wall. I have never seen an exterior wall built on top of a 4" slab, gable end included. He believes because it has no floor or roof load, there is no requirement for a footing.
R302.2.4 Structural independence.
Each individual townhouse shall be structurally independent.
Exceptions:
1. Foundations supporting exterior walls or common walls.
2. Structural roof and wall sheathing from each unit may fasten to the common wall framing.
3. Nonstructural wall and roof coverings.
4. Flashing at termination of roof covering over common wall.
5. Townhouses separated by a common 1-hour fire-resistance-rated wall as provided in Section R302.2.
Now the above section only allows the "foundation" under the common wall to be shared and not "structurally independent", but it still needs to be a foundation, correct?
So again would you consider the "interior slab" acceptable as the "foundation" required for the firewall?
I say absolutely not!!
Also on another note, pertaining to U305. He has been allow to build one wall and then attach the 5/8" drywall for the second wall to it before building the second wall next to it. My understanding is that the drywall MUST be attached to it's corresponding wall and not the wall next to it, correct?
I told him he would have to attach the drywall to second wall first before standing it up next to the first wall. would that be correct?
Thanks!
I have a contractor who wants to amend his plans to eliminate the footing between units. He says "what do I need that for, it only holds drywall?" First of all it will be supporting two one hour walls with 5/8" Type x on each side three stories tall! (UL Design U305) He wants to pour ONE 4" thick slab across ALL 6 units without the separating foundations.
R302.2 Townhouses. Each townhouse shall be considered a separate building and shall be separated by fire-resistance-rated wall assemblies meeting the requirements of Section R302.1 for exterior walls.
My interpretation of the above section requires a perimeter foundation for "each" unit including the "common" fire wall. I have never seen an exterior wall built on top of a 4" slab, gable end included. He believes because it has no floor or roof load, there is no requirement for a footing.
R302.2.4 Structural independence.
Each individual townhouse shall be structurally independent.
Exceptions:
1. Foundations supporting exterior walls or common walls.
2. Structural roof and wall sheathing from each unit may fasten to the common wall framing.
3. Nonstructural wall and roof coverings.
4. Flashing at termination of roof covering over common wall.
5. Townhouses separated by a common 1-hour fire-resistance-rated wall as provided in Section R302.2.
Now the above section only allows the "foundation" under the common wall to be shared and not "structurally independent", but it still needs to be a foundation, correct?
So again would you consider the "interior slab" acceptable as the "foundation" required for the firewall?
I say absolutely not!!
Also on another note, pertaining to U305. He has been allow to build one wall and then attach the 5/8" drywall for the second wall to it before building the second wall next to it. My understanding is that the drywall MUST be attached to it's corresponding wall and not the wall next to it, correct?
I told him he would have to attach the drywall to second wall first before standing it up next to the first wall. would that be correct?
Thanks!
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