# Underlayment - staples or screws



## joecaption (Nov 30, 2011)

Hope your not using loun as an underlayment.
I've used a pneumatic narrow crown staple gun for this job for at least 10 years and never had one back out.
They also make such a tiny hole they do not needed to be filled and it's super fast when the trigger is set to touch and go.
Never use screws when doing underlayment.
It would leave raised spots where they crush the wood and would all have to be filled and sanded.
A few other rules, the fasteners need to be every 4" on the edges, 6 to 8" in the field.
There is no need for any gaps between the sheets.
Do not nail into the joist, the goal is to pull down the underlayment so it makes full contact with the subfloor between the joist.


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## rusty baker (Feb 13, 2009)

I have been using staples for at least thirty years. The first 10 or so, we had a stapler we hit with a hammer. I have never had a problem. Screws can cause the plywood to pucker. Make sure you use underlayment grade plywood. Luan has voids in the plys which can collapse and luan can also bleed and stain vinyl.


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## Nestor_Kelebay (Jun 17, 2008)

I have absolutely no doubt that staples would go in faster than screws and would hold well.

However, I too have a pneumatic staple gun which I intended to use for installing underlayment on a bathroom floor in my building. The reason why I didn't use it was because the staples held TOO well. I wouldn't have believed that I would be unable to remove those staples, but that's exactly the reason I didn't use the staple gun.

Apparantly, narrow crown pneumatic staples have a resin coating on them which melts with the friction associated with driving them into the wood. That resin then solidifies once the staple is in, effectively gluing the staple in place.

I tried gripping one of those staples with a small pair of vice grips and using a pry bar to pull them up, but the staples would break before they pulled out of the wood. I contacted the customer service desk for Superior products who made both the staple gun and the staples, and they suggested I use a shorter staple, and that didn't help either.

I finally snapped chalk lines and drilled and countersunk holes in my bathroom underlayment and used my drywall gun to screw the underlayment down with 1 1/4 inch drywall screws. I used joint compound to patch the drywall screw locations so that if and when I ever wanted to remove that underlayment I could dig out the screw heads quickly and easily.

If I hadn't had a problem with the staples being so difficult to remove, I would have used staples. However, I could see that if I ever wanted to remove that underlayment, it was going to take as much time and effort pulling the underlayment up and grinding the staples down flush with the wood as predrilling and countersinking for drywall screws anyhow.

Everyone doing this kind of work commercially will use staples because of the speed that staples allow. In my case, however, speed was NOT the primary consideration; the ability to remove and replace the underlayment played more importance in the decision making process.

That was my experience anyhow.

Also, people should know that there's a difference between plywood and plywood underlayment. Plywood is allowed to have voids in the interior plies, whereas with underlayment, any voids in the interior plys are filled with water putty. Doing that prevents potential "soft spots" in the underlayment that could cause problems with the flooring installed over the underlayment.


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## rusty baker (Feb 13, 2009)

I have removed a lot of stapled underlayment. a simple pry bar under the edge will lift the whole sheet without much effort. And joint compound should never be used as floor fill. Floor fill should be cement based not gypsum.


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## JazMan (Feb 17, 2007)

The staples are indeed rosin coated and the rosin glue melts with the friction. They are also divergent, so they hold well. 

I've never had the problem of them breaking while removing those that didn't come up with the sheet of underlayment though. A pair of channel-lock type plies, (with the curved jaws) works well. I usually just hammered them in however. 

Don't use gypsum crack fillers as Rusty said, only Portland based.

Jaz


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## joecaption (Nov 30, 2011)

Sorry Nester, most of that post was wrong.
Drywall screws should never be used, there going to rust and bleed through the flooring.
Once they rust there not going to be holding anything.
Pretty general statement that plywood has voids.
Depends on the grade of plywood.
Underlayment grade plywood has exterior glue and all the voids are filled.
Last thing I'd be worried about when doing a quality floor install is worrying about how hard it's going to be to undo it.
If that was true we should be building the whole house with screws.


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## Nestor_Kelebay (Jun 17, 2008)

File this thread under "Your Mileage May Vary".

No one posts on one of these DIY Q&A forums with the intention of giving bad advice. We each have different opinions because we have each had different experiences.

My experience using staples was a dismal one. And, my opinion on using staples for installing underlayment is based on that experience. For me to pretend to agree with someone else only because they have more experience doing this kind of work than I would be a disservice to the OP. He asked for opinions, and now he's aware that pulling those staples out in future could be a challenge.


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## rusty baker (Feb 13, 2009)

No offense Nestor, but I think most DIYers want to do the jobs the same way as a pro., if possible. I have been installing for a living since 1973. Except for the first few years when I hand nailed with ring shank, I have stapled underlayment. The right way, best way and easiest is to staple it. 
If they screw it, they will need to use galvanized screws. It can pucker the plywood and they have to fill every screw head. Just more work.


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## Glenn123 (Nov 5, 2021)

rusty baker said:


> No offense Nestor, but I think most DIYers want to do the jobs the same way as a pro., if possible. I have been installing for a living since 1973. Except for the first few years when I hand nailed with ring shank, I have stapled underlayment. The right way, best way and easiest is to staple it.
> If they screw it, they will need to use galvanized screws. It can pucker the plywood and they have to fill every screw head. Just more work.


You are so right. And why when you are putting underpayment down would you be worried about removing it. It’s suppose to be permenant. most professionals use staples that are coated that do not penetrate the 3/4 flooring. In other words if flooring is 3/4 plus 1/4 ply underpayment use 5/8 to 3/4 staples.


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## GCTony (Jul 21, 2021)

rusty baker said:


> No offense Nestor, but I think most DIYers want to do the jobs the same way as a pro., if possible. I have been installing for a living since 1973. Except for the first few years when I hand nailed with ring shank, I have stapled underlayment. The right way, best way and easiest is to staple it.
> If they screw it, they will need to use galvanized screws. It can pucker the plywood and they have to fill every screw head. Just more work.


The first day on my new carpentry job was to install 1/4" luan using ring shank nails, 4" apart. I was pretty fast because the job I left, I was a piece rate drywall hanger so I could work with a handful of nails at a time and set and one hit. 

My wife just mentioned about changing out our ceramic tile floors, about 1200 feet of the stuff. Under that tile is 3/8" plywood, attached with 1 1/4" crown staples, about 4" OC. I think I'll just burn it.


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## ront02769 (Nov 28, 2008)

So the tile guys will now give you crap about laying on plywood…..but 35 years ago that was the standard where I live.


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## Half-fast eddie (Sep 19, 2020)

Nothing wrong with using luan for underlayment … as long as it is stamped “underlayment grade”.


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## Randy Bush (Dec 9, 2020)

Years ago before I know any better I nailed down underlayment with ringshank nails. Was laying down the 12x 12 1/8 Armstrong squares over time those nails shower though because did not skim coat over them. Now just staple it down.


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## chandler48 (Jun 5, 2017)

Good points reviving a 6 year old thread.


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## ront02769 (Nov 28, 2008)

gc tony revived the thread. Figuring that there are many like me that see a thread and don’t bother look at how long ago it died.


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