Residential Wood: Plywood sheathing all around exterior & design dead load

They use exterior insulating board where they can to meet energy standards.

Wait, your projects have portions of your wall with no sheathing? I can't comprehend that.

I use 20psf for my typical exterior wall weight and if conventional stucco I use 25. If stone then I use 20 plus the weight of stone.

It may be that I might have been on the job site during the earlier stage of the construction...

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Isn't there a spec, or drawing you can check? Or talk to some one?

In New Zealand and Australia this type of construction is common as well. blew my mind when I first saw it. Paper stapled right over the studs, no sheathing to support the paper.

Here is a nice little article that outlines why things have developed in the way they have, that differs by location. "Need, Greed and Speed"


Construction standards for houses in these warm climates tend to resemble garden sheds built in areas with cold climates, mainly because they dont really need to be built any better. Occupants suffer for the 1-2 months of year where temps dip below 15C/60F, layering up in many jumpers, or huddling around a space heater. The rest of the year they can happily relax with all the windows open.

Here is a great photo I took down under. It had been a bit windy lately, so to protect the paper of this house under construction, the contractors had fastened sheets of plywood temporarily over the paper to protect the paper from getting sucked off until the siding can cover. made me chuckle

Two quotes from linked paper (provided by NorthCivil).

So what was the function of the building paper? Ah, easy question, with clapboards and board sheathing it was to reduce drafts.

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Even more sophisticated are insulating sheathings that combine not only the functions of a sheathing and housewrap but also provide thermal resistance (really, they are sophisticated even though these products were first introduced in the 1950’s). There is even an insulating sheathing available that provides shear resistance.

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Davab:
In some of the older USA bldg. codes, you used to be able to use several sheets of plywood at the corners in each direction, as the lateral bracing, to a take the required lateral loads in the wall, and then infill the remainder of the wall with a lesser value/strength sheathing of the same thickness. This provided a lateral bracing improvement over the older let-in diag. bracing, which was then often covered with 1x4 or 1x6 ship-lap horiz. sheathing or a light fiber board sheathing. The let-in diag. bracing could be eliminated by installing the ship-lap sheathing diagonally. But, in So. Calif., I can’t imagine that those walls don’t get fully sheathed with plywd. to accommodate EQ’s., and many times the edge and field nailing is much tighter spacing than normal. You better find out what the builders are doing on these walls, and you better figure out what you should be doing and calling out. EQ areas have much stricter wall sheathing req’mts. than most other areas.

dhengr said:

In some of the older USA bldg. codes

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I believe it still exists. I doubt many licensed engineers in their right minds would allow it on a project they spec'd, but the IRC only requires that exterior wall coverings and their attachments be capable of resisting design wind loads. In a lot of places, fiber-cement siding nailed to studs at 16" o/c will do that. Furthermore, the IRC lists 16 types of braced wall construction. Only 4 of them are considered "Continuous Sheathing Methods" that require structural panels over the entire house. See table R602.10.4.

I'm not advocating for it - I'm just surprised that so many people are surprised by this. I lived in a house built in the 90's that could be broken into with a hammer. Beat on the wall between two windows and away from a corner: you'd pound through vinyl siding, 1/8" particle board, pull out some insulation, pound through 1/2" GWB and there you go - a 14.5" opening into the house.