OSB vs Plywood: Which One Wins?

Summary

This video compares OSB and plywood for roof decking through various tests. It evaluates nail holding, water absorption, and structural strength. Plywood wins the nail test, but OSB excels in water absorption and is less susceptible to delamination and termite damage. The video concludes that OSB is the superior choice for roof decking due to its performance in real-world applications.

Takeaways

• 📐 **Nail Holding Test**: Plywood outperformed OSB in holding nails, with an average of 77.1 lbs compared to OSB's 28 lbs.
• 💧 **Water Absorption Test**: Over 4 days, OSB absorbed only 5 oz of water, while plywood absorbed 7 oz, indicating OSB is more water-resistant.
• 🏗️ **Strength Test**: Plywood could span greater distances without breaking compared to OSB, suggesting it's stronger for longer spans.
• 🔍 **Moisture Spread**: OSB showed less moisture spread than plywood, which could be beneficial for preventing water damage.
• 🏡 **Practical Application**: The presenter believes OSB is superior for roof decking due to its water resistance and less susceptibility to damage.
• 🐛 **Termite Resistance**: OSB is less likely to be eaten by termites compared to plywood, which has more wood content.
• 🔄 **Delamination**: Plywood is more prone to delamination over time, which can lead to the need for full sheet replacement.
• 🛠️ **Construction Practice**: In real-world scenarios, small OSB sections can be replaced easily, whereas plywood damage often requires larger replacements.
• 🔩 **Nail Pull Test**: While plywood won the nail pull test, the presenter doesn't consider it a major factor due to shingles being more likely to blow off.
• 🏋️ **Weight Test**: The presenter tested the板材 by standing and jumping on them, finding both materials impressive but ultimately favoring OSB for everyday use.

Q & A

What is the main objective of the video?

The video aims to determine whether OSB or plywood is a better material for roof decking by performing various tests on both materials.

How does the presenter test the nail-holding strength of OSB and plywood?

The presenter drives three nails into both OSB and plywood samples, pulls on each nail with a scale, measures the maximum weight they can hold, and averages the results to compare the nail-holding strength of the materials.

What were the results of the nail-holding strength test?

Plywood had an average nail-holding strength of 77.13 lbs, while OSB averaged 28 lbs, making plywood the clear winner in this test.

How was the water absorption test conducted?

The presenter weighed both materials, submerged them in water for four hours, and then measured how much water each absorbed. The materials were then submerged for an additional three days before the final water absorption measurements were taken.

What were the results of the water absorption test after four days?

After four days, both OSB and plywood had absorbed 36 ounces of water, but OSB absorbed less water overall (5 oz) compared to plywood (7 oz), with the water spreading less in OSB.

Which material performed better in the water absorption test and why?

OSB performed better in the water absorption test because it absorbed less water and spread it less compared to plywood. This makes OSB more resistant to water damage.

How was the strength test for spanning capability conducted?

The presenter tested how well OSB and plywood could span distances without breaking by standing on them at increasing distances (from 16 inches to 36 inches) and observing how much cracking occurred.

What were the results of the spanning capability test?

Both OSB and plywood performed well in the spanning test, with plywood being slightly stronger as it could span wider distances (up to 36 inches) without breaking.

What does the presenter conclude about the delamination issue?

The presenter explains that plywood is more prone to delamination over time compared to OSB. If one sheet of plywood fails, the entire sheet may come apart, whereas OSB's structure limits failure to localized areas, making it more durable.

Why does the presenter prefer OSB over plywood for roofing?

The presenter prefers OSB because it absorbs less water, has better localized damage control, is less prone to delamination, and termites are less likely to target OSB than plywood.

Outlines

00:00

🔨 Nail Pull Test: OSB vs Plywood

The video begins by exploring the nail-holding capabilities of OSB and plywood for roof decks. Three nails are driven into samples of each material, and a scale is used to measure how much weight each nail can hold before being pulled out. The test results show that plywood holds up significantly better, with an average pull weight of 77.13 lbs compared to OSB's 28 lbs. The video suggests this is due to the uniform structure of plywood, making it a stronger material for nail retention.

05:03

💧 Water Absorption Test: OSB vs Plywood

Next, the video tests the water absorption of both materials. Plywood and OSB are submerged in water, first for 4 hours and then for 3 days. The results after 4 hours show that plywood absorbed more water (3 oz) compared to OSB (2 oz). After 4 days, both materials absorbed the same amount (7 oz), but the spread of water in the plywood was more extensive due to its structure. This indicates that while plywood pulls up more water, OSB is less susceptible to water damage, making it the winner in this test.

🏋️‍♂️ Strength and Span Test: Plywood vs OSB

The video then focuses on strength by testing how far plywood and OSB can span while supporting the presenter's weight. Starting at 16 inches, both materials hold up well. As the span increases to 24, 28, and eventually 32 inches, both plywood and OSB continue to impress, with only minor cracking sounds. Finally, at 36 inches, plywood holds up better, taking the lead in this test, demonstrating superior strength at wider spans, though the presenter admits both materials exceeded expectations.

🤔 Final Thoughts: Plywood vs OSB

The video wraps up by analyzing the results of the tests. Plywood proved stronger and better at holding nails, but the presenter believes these advantages are less significant when considering real-world applications, as both materials perform well in common roof spans. OSB is highlighted as superior in water resistance and easier to repair when damaged, as localized repairs are more common. The presenter notes that OSB also resists termites better and doesn’t delaminate like plywood. Overall, OSB is preferred for practical reasons, though the audience is invited to share their thoughts on plywood’s advantages.

Keywords

💡OSB

OSB stands for Oriented Strand Board, which is a type of engineered wood similar to plywood but made from compressed wood strands. In the video, OSB is compared to plywood for use in roof decking. The script describes tests comparing nail holding, water absorption, and structural strength between OSB and plywood, with OSB showing less water absorption and potentially better resistance to termites.

💡Plywood

Plywood is a type of engineered wood made from thin layers of wood veneer glued together. In the video, plywood is compared to OSB for roof decking applications. The tests conducted in the script reveal that plywood holds nails better than OSB but absorbs more water and is more susceptible to delamination and termite damage.

💡Nail Pull Test

A nail pull test is a method of assessing the holding power of nails in different materials. In the script, the nail pull test is used to compare the grip strength of nails in both OSB and plywood. Plywood is noted as the winner in this test, but the narrator suggests that this might not be a significant factor in real-world roof deck applications.

💡Water Absorption

Water absorption refers to the process by which a material takes in water. The video script describes a test where both OSB and plywood samples are submerged in water to measure how much they absorb over time. OSB is highlighted as the clear winner in this test, absorbing less water than plywood, which is an important consideration for roof decking materials.

💡Span

In the context of the video, 'span' refers to the distance between structural supports, such as roof rafters. The script details a test where the narrator stands on OSB and plywood samples at increasing spans to evaluate their strength. Plywood is shown to span larger distances before showing signs of failure compared to OSB.

💡Delamination

Delamination is the process where layers of a material separate. In the script, the narrator discusses the issue of delamination in plywood, where the layers can come apart over time, especially in older roofs. This is contrasted with OSB, which does not suffer from delamination in the same way due to its construction from wood strands.

💡Termites

Termites are insects that feed on wood and can cause significant damage to wooden structures. The video script mentions termites in relation to the durability of plywood versus OSB. It is suggested that termites are less likely to damage OSB because they prefer the larger wood pieces found in plywood.

💡Roof Deck

A roof deck is a structural component of a roof, typically the layer on which shingles or other roofing materials are installed. The video script is focused on determining the best material for a roof deck, comparing OSB and plywood in various tests to see which is more suitable.

💡Moisture Meter

A moisture meter is a device used to measure the level of moisture in a material. In the script, a moisture meter is used to assess how far water has spread in both OSB and plywood samples after they have been submerged. This helps to evaluate how each material handles water intrusion.

💡Uniform Surface

A uniform surface is one that is consistent in texture and composition. The narrator in the script suggests that plywood provides a more uniform surface compared to OSB, which might have weaker pockets. This uniformity could affect how well nails hold and how the material performs under stress.

💡Engineered Wood

Engineered wood is a type of man-made wood product that is made by binding or fixing the strands, particles, fibers, or veneers of wood together with adhesives to form composite materials. Both OSB and plywood are types of engineered wood, and the video script compares their properties and performance in the context of roof decking.

Highlights

Nail holding test to determine which material grips nails better between OSB and plywood.

Plywood shows superior nail holding capacity with an average of 77.1 lb compared to OSB's 28 lb.

Plywood's even and consistent sheets provide a more uniform surface for nail holding.

Absorption rate test to see how much water OSB and plywood can absorb over time.

OSB absorbs less water than plywood, indicating better water resistance.

After 4 days, OSB absorbs only 5 oz of water while plywood absorbs 7 oz.

Strength test to see which material can support more weight over a span.

Plywood holds up under a 32-inch span without breaking, showing its strength.

OSB shows no signs of failure even at a 28-inch span, but plywood performs slightly better.

In real-world applications, OSB's water resistance is more important than plywood's strength.

Delamination is a concern for plywood but not for OSB, making OSB a more reliable choice.

Termites are less likely to damage OSB compared to plywood due to the lack of large wood surfaces.

The presenter's personal preference leans towards OSB for roof decking due to its water resistance and durability.

Plywood's strength is acknowledged but not deemed as critical for applications spanning 12 to 24 inches.

The nail pull test, though significant, is not considered a major factor in the decision-making process.

The water absorption test is considered a real-world application that favors OSB.

The final recommendation is OSB for new roof sheeting installations.

Transcripts

in this video we're going to be answering the age-old question: OSB or plywood?

which one should you use for your roof deck?

we're going to be performing different tests to find the answer. let's get into it!

in this test I want to find out how well nails hold on to both OSB and plywood

and see which one does a better job grabbing onto nails

the way we're going to be doing this is I've driven three nails into both this sample of OSB and into a sample of plywood

all three nails are sticking out half an inch and all three nails on both boards are the same thickness and material

that way we have an even test we're going to be testing each three nails separately

we're going to pull on with a scale and see the maximum amount of weight each nail holds

average those out and get a good comparison between both OSB and plywood

first off we're going to test the plywood then we'll move on to the OSB

all right so we got 87.7  lb on the first one

we have 71 lb on the second test

and lastly we have 72.7 lb on third one

now that we're done testing the CDX plywood we're going to be testing the OSB next

for our first result we have 24.8

we have 17.9

and lastly we have 13.4

in this test the plywood is the clear winner

77.1 3 versus 28 the OSB you might have pockets that are weaker

 where as opposed to plywood is made of even and consistent sheets providing a more uniform surface

let's move on to our next one

what I want to test now is the absorption rate of plywood and OSB

now we're weighing the plywood so we're at 29 oz and the OSB is weighing in at 31 oz

We're going to see how much it absorbs in the first 4 hours, then we're going to give it 3 days. let's get started

in order to do a fair test, both these are hand cut and more likely to absorb in moisture

and's place these in all right we're about 4 hours into our test

I'm going to weigh it so we'll know how many ounces of water was absorbed

the second thing I want to do is measure with a moisture meter the spread of water to see how far water has spread

so let's start off by measuring the OSB, so we're at 33 Oz

and we're at 32 oz of water for the plywood the plywood  has absorbed 3 oz of water and the OSB just two

now let's mark out the spread of water

all right so what I'm finding here is the moisture is only spread to about an inch above the water line

so our OSB was submerged into water from about here

and so far we have moisture showing an inch above that

now our plywood visually I can see that it's already a little bit more than that

so our plywood has traveled in a interesting pattern

you can see a lot farther up so they were both submerged up to about 2 inches

the plywoods pulled up a lot more water, which is what I was expecting

the way trees work is pulls water right from the roots all the way to the top of the tree

so there's essentially veins where OSB has smaller particles of wood

there's not a consistent place for the water to travel

now we're going to put these back, we're going to come back in 3 more days

and see over a longer exposure what's going to happen to both these samples

both Plywood a nd OSB have been  sitting in this water for about 4 days

and now we want to measure it for the second time to see how much water we've absorbed

we are at 36 Oz for the OSB

now let's measure the plywood and see

interestingly we're at 36 Oz for the plywood as well

the OSB hasn't absorbed any more water, it's come up maybe a quarter of an inch

so you can see here's our line for the first test

this second line here is after 4 days so the difference is very small

however the difference  in the OSB was even less

overall I would say the clear winner in this test is definitely the OSB

it only absorbed 5 oz of water in 4 days whereas plywood absorbed 7 oz of water in 4 days

the spread of OSB was a lot less whereas plywood spread a lot more

bottom line this round goes to OSB

in this test I'm going to be putting my health and well-being on the line to answer which is stronger

by seeing which one can span  further and still hold me up

all right let's see how this goes

all right looks like I'm safe on this one. so we've got a 16-in span

I heard a little bit of cracking but the plywood is holding up well

it's time test the OSB I'm going to stand in the middle both my feet on one line right in the center

so glad to say there's no cracking and it seems like I'm safe for now

now I put the span at 20 in I got to say I am a little bit nervous but let's see how this goes

looks like I'm still safe for now just hear  some little cracking but that's about it

now it's time to test the OSB, again I'm going be standing right in the middle

and looks like I'm safe for now next we're going to be moving up to 24 in

all right now we're at a 24 inch span I'm going to put our plywood on and see what happens

24 inches is the widest generally roof rafters are spanned

all right looks like I'm safe for now  I'm not moving any of my weight  

again just I hear light cracking when I'm on the CDX   

now it's turn for OSB

all right seems like I'm good

I'll be moving up from 24 to 28 in

all right I'm getting nervous

now we're at a 28 inch span, now realistically this is wider than any standard roof would be so

little nervous here

all right seems like I'm safe for now

I got to say both these materials are impressing me, I would have expected a break by now

next I'm going to go to a 32 inch span and see what happens then

all right we are at 32 in and ready to test

all right I am pretty impressed,  I'm going to do a light bounce right now

and it seems like this is holding up well

time to test the OSB

all right seems like this is safe

I'm going to do a light bounce

next I want to move up to 3 feet, this is quite an extreme span

still nothing I'm going give a little jump

we got a good bounce there

all right now it's time to test the 36 in OSB

there we have it plywood spans bigger and longer than the OSB I guess

I think it's safe to say that plywood takes this round

now that our tests and experiments are done

it's time to put our thoughts together and see which one takes the lead

plywood is stronger however that to me is not as important

because we're spanning between  rafters that range between 12 to 24 in

both of these perform just fine so the results of that test was interesting

but I wouldn't say it weighs my decision or my opinion too heavily on the side of plywood

the next test we did was the nail pull test

plywood did take the clear win, however to me I  don't think it's a huge indicator of which one's better

if we're going to have blowoff it's usually going to be the shingles that blow off and the nails that stay

the next test we did which in my opinion is huge is which one absorbed more water

and OSB was a clear winner of that and again  we can see that OSB only took in a little bit of water

while plywood absorbed a lot more and absorbed more weight

anytime we're replacing an OSB roof what we see is small sections get damaged

small sections get replaced and we're ready to move on

what we see in plywood, anytime there's  a leak, the entire sheet get damaged

or half a sheet or two three sheets in that whole area need to be replaced

so in my opinion this test is a real world application

OSB takes the lead, that's one reason I think OSB is going to be the superior product

the other item that we were not able to test was what we call delamination

if we have a roof that's maybe 40, 50 years old, we find heavy delamination

that we have to replace the entire plywood because the sheets of the plywood are delaminating

meaning they're coming apart, I think why this happens more often on plywood than it does on OSB

is because if one sheet starts failing that entire sheet can start opening up

as opposed to OSB if one of these small chips fail your failure is limited to just one location

because you have so many strands of wood that are coming together

if one part of it is failing it doesn't mean the entire sheet fails

on the other hand plywood fails as a sheet

lastly we have termites plywood you have  thick sheets of wood that are glued together

termites don't like glue they don't like chemicals, they like natural wood

and plywood you have a lot more wood for termites to eat than you do on OSB 

termites will kind of burrow in between the plies and will eat out the plywood

I don't think I've ever seen OSB being eaten by termites

if all things were equal and you're going to be installing  new sheeting on your roof I would personally pick OSB

if you think I'm wrong let me know below

I would love to hear why you think plywood beats OSB