Using "OSB" for flooring in New Construction? -Thats just SWELL!

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Home Inspector with H.I.S. Home Inspections (Summit, Stark Counties)

Wow, I just realized that the first part of this blog is entirely missing, I apologize. I wrote it, but it somehow disappeared. Anyway, OSB (stands for "oriented strand board") is a builiding sheet material that is commonly used in building new homes. It is used on roofs, exterior sheeting, and ... for sub-flooring. Builders like it because it is cheaper than plywood, therefore it has pretty much taken the place of plywood in the building industry. There is however, one precaution when using this material; when it is used for sub-flooring in new construction applications. It should be kept relatively dry during the construction process, and before the roof is put on to help protect it. Why should it be kept dry? Because of this materials tendency to SWELL up when it gotten overly wet, and not allowed to dry properly. Because of it being used for flooring, which is supposed to installed basically flat and level, if it rains the material can become saturated, swell up to 1 1/2 times its original thickness, and also, lose overall strength and durability.

Therefore, precautions should be taken to ensure that it stays dry. If you build, and it rains before the roof has been applied, then the sub-floor should be broomed dry afterwards, and if there is any remaining puddles, a small (3/8 inch) hole should be drilled in the floor to help it drain out. This will help prevent swelling and loss of strength in the material.

OSB that has swellled considerably should be replaced. If it is not, then strength of the floor will be lost, the floor will have high spots, and probably be noisy to walk on. I have seen several builders just ignore this, and do nothing about it.

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Rainer
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R. B. "Bob" Mitchell - Loan Officer Raleigh/Durham
Bank of England (NMLS#418481) - Raleigh, NC
Bob Mitchell (NMLS#1046286)

Unfortunately, most home buyers aren't going to know if this building material was propertly installed until the grout starts cracking or the floor otherwise becomes unlevel...wouldn't you agree?

 

Bob Mitchell

ValueList Real Estate Services, Inc.

Jul 01, 2008 08:15 AM #1
Rainmaker
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Kevin Corsa
H.I.S. Home Inspections (Summit, Stark Counties) - Canton, OH
H.I.S. Home Inspections, Stark & Summit County, OH Home Inspector

Yes Bob,

It can be hard to spot, especially in the middle of a room or floor. But if they know it rained, they can tell their builder to make sure the water gets removed, or go check themselves.  

Jul 01, 2008 08:22 AM #2
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Lenn Harley
Lenn Harley, Homefinders.com, MD & VA Homes and Real Estate - Leesburg, VA
Real Estate Broker - Virginia & Maryland

Everytime a builder tells me that OSB is better than plywood for subflooring, I know that they are big fat liars and listen to anything that they say afterwards with a grain of salt.  I don't care if it is 3/4" thick.  It is still OSB. 

Up until about 5 years ago, my new home buyers could pay for a plywood upgrade but builders don't even offer that today. 

I've been in homes with web basements where the first floor subflooring swelled up to a point where it had to be ripped out. 

I've been in homes with 1/2 inch OSB subflooring that was like a tranpolene. 

Fact is, builders save money wtih OSB.  That is the beginning and end of it. 

 

Jul 01, 2008 08:40 AM #3
Rainer
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Frank Schulte-Ladbeck
Frank Schulte-Ladbeck Professional Real Estate Inspections - Houston, TX

Just taking a look around a construction site, and I am seeing so much material left out in the rain with no cover. I would hate to see them use OSB after it has been out in that.

Jul 01, 2008 12:19 PM #4
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TeamCHI - Complete Home Inspections, Inc.
Complete Home Inspections, Inc. - Brentwood, TN
Home Inspectons - Nashville, TN area - 615.661.029

Kevin... All new builds here in our area use OSB... One advantage of this material is that it is less expensive to manufacturer than plywood and it helps cut down on the number of trees used to make a house... This is good for our environment... True about the water, but in the long run, water does not appear to adversely affect the material like some of the older building materials... Must be better glue...

Jul 01, 2008 09:11 PM #5
Rainmaker
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Kevin Corsa
H.I.S. Home Inspections (Summit, Stark Counties) - Canton, OH
H.I.S. Home Inspections, Stark & Summit County, OH Home Inspector

Michael,

I have seen when water affects OSB, and believe me, it can get pretty ugly. I don't have a problem with the use of the material, like I said, but I believe that some precautions should be taken during construction to prevent the damage, and it should not be swept under the rug (so to speak) by the builder.

Jul 01, 2008 09:57 PM #6
Rainmaker
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Atlanta's Home Inspector, David Lelak IHI Home Inspections
IHI Home Inspections 404-788-2581 - Canton, GA
Experience the IHI Difference

Great post, and I agree when it is kept dry it is a great product.  We just had our roof replaced because of hail damage and they brought some sheets out to fix things and left it out.  We did move it into shelter because we didn't want our roof to swell right up.

Jul 02, 2008 02:19 AM #7
Rainmaker
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Kevin Corsa
H.I.S. Home Inspections (Summit, Stark Counties) - Canton, OH
H.I.S. Home Inspections, Stark & Summit County, OH Home Inspector

David, Nice to hear from you again. Thanks for stopping by.

Jul 02, 2008 02:23 AM #8
Rainmaker
67,128
Kevin Corsa
H.I.S. Home Inspections (Summit, Stark Counties) - Canton, OH
H.I.S. Home Inspections, Stark & Summit County, OH Home Inspector

I understand the concept of saving trees and resources, and for that reason alone, it is a good product. We just need a little more care and education when using it in all these different applications.

Jul 05, 2008 01:32 AM #9
Rainmaker
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Atlanta's Home Inspector, David Lelak IHI Home Inspections
IHI Home Inspections 404-788-2581 - Canton, GA
Experience the IHI Difference

Kevin, with summer here we have been busy and Bonnie went to visit her mom and the pool and refused to take the computer and I just didn't have time.  Hopefully when school starts back up, she will be back and pick up where I slack.  Have a great week.

Jul 08, 2008 01:11 PM #10
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Rainmaker
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Kevin Corsa

H.I.S. Home Inspections, Stark & Summit County, OH Home Inspector
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