Which is better - OSB or plywood

Contractors are usually after the biggest bang for the buck. I did high end multiple zone comfort systems (HVAC). The controls were, at the time either Carrier, Trane, or Honeywell. These systems used a series of networked thermostats, return air sensors, supply air sensors, and outdoor temperature sensors. If installed they could be connected via internet connection for reprogramming or just monitoring. If properly designed the systems could cut operating costs considerably but their main attraction was in the ability to heat/cool the whole house effectively by zones where one thermostat could only satisfy the temperature at it's one location. I had homes with 10-12 zones that were balanced by separate thermostats in each zone that kept the entire home comfortable and each thermostat was programmed for its needs by time and temperature. It was a major advance in home comfort and troubleshooting of the system was possible remotely.

Then I did homes of comparable size and worth that used contractor grade equipment, fiberglass ductboard, and a few central returns. These systems I wouldn't put in my own home for several reasons the 1st being ductboard is a material made of fiberglass sheeting material that has a rough surface and over time the fiberglass particles come loose and gets blown into the air stream. So lower air flow due to resistance, uncomfortable when the fiberglass particles get blown on you, and far less efficient equipment and operating conditions. And many of these in very expensive developments. The money was spent on what you could see. Appliances, lighting and plumbing fixtures, and so on. Comfort was secondary and easy to cut cost on so when a contractor uses material of lesser quality it often has to do with what can be seen and quantity. The bottom line is profit.

The only reason it is used extensively is the cost ! there is a huge saving, the average person doesn't see it because we only buy a few sheets at a time. When a contractor builds several homes as you mentioned higher price range means larger means more square feet means more sheets. If the savings are close to $10 per sheet, imagine when you're buying a truckload !!! we are talking thousands of dollars. I sell equipment to panel mills across Canada and sometimes I am amazed at how much of this stuff is consumed. I use it for some applications but I much prefer plywood for being solid mass. My shop walls are all OSB and I must find studs to screw anything substantial to the walls. I was teaching my students yesterday about the different sheet goods and their applications and I said if I ever win a lottery and have a high end home built, it would be plywood, not OSB. The manufacturing cost is much lower because the fibre used can be in any type of wood and some low quality trees are used for the savings. Everything gets shredded to the size you see on a finished sheet and then it's dried to remove the moisture, then formed in several layers of a combination of these shavings and glue, which is then pressed with tons of pressure and heat to form the large sheets that are then cut to 4' x 8'. There is a coating on one side that is somewhat weather resistant but I think if plywood was priced equally no one would use OSB !

When we built our home in 2002 I was recovering from bilateral arthroscopic surgery. Although it wasn't pleasant and I had the contractor I wanted I was there every day to oversee the project. The home was by our design and the blueprints were revised very slightly by the builder as I was open to suggestions. I had several bids on the build and they were all close but I did question on the materials to be used. There were no shortcuts made and I was already getting a deal that couldn't be topped as the company I worked for was doing the mechanical work and I got everything at cost from those supply houses which means electrical, plumbing, and HVAC. Cost being suppliers cost not my company cost. It was a long standing deal our suppliers had with it's major commercial customers.

Framing was almost overbuilt. When I go on the roof to inspect there is no bounce. I also documented the work as it progressed. I could locate any pipe under the basement concrete floor without a problem as well as any electrical wiring path. Any and all penetrations through the studs was fire blocked. It is my strong belief that if you are paying to have a home built you need to see what is being done and how. Ask questions and take notes/pictures. The inspector is supposed to be checking that everything is to code but I really don't want to tell some of those stories. You should have seen the faces of those older inspectors when they saw me running furnace exhaust pipe using PVC pipe. Yes it was when condensing gas furnaces 1st came out and the vent gas was maybe 85 degrees. I remember having Leroy sit down on a bucket and look over the manufacture's specs. The look on his face and the many "I'll be" I heard that afternoon.

Just saying it pays to inspect the home while it's under construction and ask questions.

mgmine said:

I wish I had taken pictures of the floor I put down in a cabin in Canada. It was about 20 years ago and I was replacing a floor that was put in 50 years prior to that. The original sub floor was solid pine that I replaced with 3/4" OSB. The original sub floor was about 6" off the dirt ground. I hand dug the dirt to a depth of 4 feet thinking that would be fine. I was wrong within a few years mold started growing on the OSB and 10 years later the floor was completely rotted and had to be replaced again. The original floor that was still in place in the front of the cabin is still as solid as the day it was put down in 1939. That part of the floor had an air space of at least 3 feet. So air space caused the original floor to rot but even with 4 feet of air space the cheap OSB rotted.

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23/32 OSB 80 pounds, 23/32 plywood 60 pounds. That is 20 pounds of extra glue spread over 32 square feet. You need all of that glue to get the thousands of thin strands of wood to stick together. OSB is here to stay because of the cost. A quick search shows a 5 dollar difference in sheathing 7/16 OSB, 1/2" Plywood. 5 dollars per sheet on all of your exterior walls and roof adds up. Adds up for the builder. For my smallish house roughly 1100 square feet the extra cost would be $660. If builders presented the cost difference between the 2 sheathings I would pick plywood. What happens when the roof leaks or the vinyl siding has a crack or void and water penetrates? Then there's your flooring substrate, same thing. My ice maker leaked the dishwasher leaked the water heater leaked a pipe busted, when the water hits OSB it's a major costly problem.