Does T&G Porch Ceiling require ply. underlay? Does T&G alone act as acceptable sheathing dia
Does T&G Porch Ceiling require ply. underlay? Does T&G alone act as acceptable sheathing dia
(OP)
Hello All,
I am working on a residential single family home. The owner would like to replace typical ply. porch ceiling sheathing with tongue & groove. Can the t&g replace the ply. sheathing and still act as the diaphragm? Is it a requirement to install ply. above the t&g in order to have a more rigid horizontal ceiling diaphragm? I can find no specifications stating whether it alone can act as necessary sheathing.
Any help/advice would be great!!!
I am working on a residential single family home. The owner would like to replace typical ply. porch ceiling sheathing with tongue & groove. Can the t&g replace the ply. sheathing and still act as the diaphragm? Is it a requirement to install ply. above the t&g in order to have a more rigid horizontal ceiling diaphragm? I can find no specifications stating whether it alone can act as necessary sheathing.
Any help/advice would be great!!!






RE: Does T&G Porch Ceiling require ply. underlay? Does T&G alone act as acceptable sheathing dia
Is there no roof diaphragm to take the lateral force here?
Mike McCann
MMC Engineering
RE: Does T&G Porch Ceiling require ply. underlay? Does T&G alone act as acceptable sheathing dia
I believe for straight/parallel applications, it's only good for about 50 plf (ASD), and about 300 plf if you orient the lumber diagonally.
RE: Does T&G Porch Ceiling require ply. underlay? Does T&G alone act as acceptable sheathing dia
To: msquared48
I still need to calculate the resisting load. I am trying to avoid projecting an extra cost to the contractor/owner if it isn't necessary to install ply. in conjunction with the t&g. I would love to just use the t&g standalone approach. I do worry that the t&g will not work as a functional diaphragm. In the case of a porch extending outward from exterior walls; I feel you would need the ceiling sheathing to act as a diaphragm for rigidity. I find no IRC/IBC code saying you must install ply. underlay. I will have to look into the NDS values and make a comprehensive judgement if I can't find specifications and codes that allow me to use the t&g alone as the ceiling diaphragm.
RE: Does T&G Porch Ceiling require ply. underlay? Does T&G alone act as acceptable sheathing dia
Mike McCann
MMC Engineering
RE: Does T&G Porch Ceiling require ply. underlay? Does T&G alone act as acceptable sheathing dia
RE: Does T&G Porch Ceiling require ply. underlay? Does T&G alone act as acceptable sheathing dia
RE: Does T&G Porch Ceiling require ply. underlay? Does T&G alone act as acceptable sheathing dia
I understand that. But what prevents the existing roof diaphragm from taking the load?
Mike McCann
MMC Engineering
RE: Does T&G Porch Ceiling require ply. underlay? Does T&G alone act as acceptable sheathing dia
BA
RE: Does T&G Porch Ceiling require ply. underlay? Does T&G alone act as acceptable sheathing dia
RE: Does T&G Porch Ceiling require ply. underlay? Does T&G alone act as acceptable sheathing dia