Stairway & Treads: Remodel Questions

[Rantz Phelps]

Hey guys!

I've been avoiding finishing our home stair remodel for far too long overall! I could use some advice clearing up a bit of confusion about the behavior of one of my oak treads I made after I installed it.

Short background:

• 4-5 year old house (our 1st house). Sunny/hot Florida!
• Ripped up carpet.
• OSB treads underneath
• Made Oak Treads from kiln dried red oak. Joined boards together with biscuits for alignment. Treads are actually 3/4" thick so I glued on a thicker portion for the overhang to give it the appearance of 1" thick. Used 1/2" radius roundover to give them a full semicircle profile for the overhang lip. Nailing & gluing them on top of the existing treads.
• Making the flooring for the 2 landings out of the same wood to match color and height so there won't be any weird variations.
• Stained & finished TOPS ONLY. Left the end grain and the bottom sides unfinished.
• Closed sided stairway with skirt boards.
• Made the stair tread jig by blazingnailgun on youtube to help me fit the treads and riser faces to fit the irregular angles
• Using Liquid Nails "Subfloor" adhesive as it has slightly longer working time and seemed more appropriate. Using 18 gauge nails to face nail just the back edge where the new 1/2" plywood riser faces will cover up the nail holes. I've sat and stood on them for a little bit each time when moving on to the next stair to help them adhere.

Okay now on to my issue/question:

On the most recent tread I've installed, everything was normal and flat at first. However over the course of a few days, I noticed that the height felt a bit off (higher) when coming up the installed stairs below it. Didn't think too much about it as I was busy. Then it felt more. Was I crazy? Then I bounced on the edge once just to feel it out and it moved some. "That shouldn't be happening with the liberal amounts of glue that I used!"

Well looky here! Yeah, that's about a 3/16" of an inch of gap in the center of the tread.

So my question is: Can a liberal amount of Liquid Nails "subfloor" adhesive lathered on the underside of a solid red oak tread introduce enough moisture to cause the bottom to expand and the tread to cup in this way? Or was there something wrong with my treads overall stability?

I'm pretty sure it's the glue, but just want to confirm as this was my first time joining boards together for the treads. The wood has had plenty of time to acclimate to my house as I store the red oak in stacks in the spare bedroom, etc. When the treads weren't being milled or finished, they were in the house to help with stability.

If it was indeed the glue that caused it, can I just put on a thin coat of the Minwax floor poly on the undersides to help repel the moisture longer while the adhesive cures? I don't want to make the mistake of using too little glue and have the treads pop and move in time. I also don't want the coat of poly on the underside to prevent it from having a secure bond. Is that a concern?

What can I do to keep this from happening?

The offending tread is actually still there since I've been too disgusted to address it until now. I'll just carefully cut/scrape/chisel it out of place without damaging the new riser face that's already glued and nailed over it. That way I can just slide the replacement one into place.

It's being weird about me trying to upload pictures.


Thanks guys for your time. I'll follow up probably with a couple more minor planning things.

[jay gill]

Based on your description it sounds like too much liquid nails is part of the issue. A zig zag pattern front to back 1.5"-2" space at the points is plenty.

Polyurethane on the backside won't block the moisture and actually makes the glue bond weaker. The poly bonds to the wood and the glue just to the poly.

You also need more mechanical fastening, i.e. nails. Three 3" 10 penny finish nails evenly spaced into each stringer. Pre-drill the treads and osb wit 7/64th, you want the nails to grab but not split the tread

I've only done one staircase, but have no issues after 4 years. I did dado the back of the tread into the riser.

IMG_0275.jpgIMG_0273.jpgIMG_0276.jpg

[Rantz Phelps]

Jay,

Thanks for the response! I knew it must have been the glue since I applied it like cake frosting on that tread because it was the last one I used that tube on and figured use up the rest of the tube.

To clarify: Since I had originally intended on attaching pictures, I wasn't as descriptive. Basically when I lay a straight edge from front to back on the offending tread, there is about a 3/16" gap in the center- that's how much it cupped and curled upwards! Also, I am installing my treads prefinished since finishing them in place would be near impossible with 2 cats and a dog. This is why I have avoided putting any nails into the stringers as you mentioned Jay.

Also, since I'm not replacing the treads as you did, and I'm just gluing my 3/4" oak ones on top of the 1" OSB treads, I was following the cue of how I have seen/read about others doing it online.

I just got done removing the naughty tread with a combo of: oscillating multitool, pry bar, hammer, chisel, very careful use of a mini circular saw & sawzall, etc! lol Now that I've scraped as much glue and high spots off the OSB treads as I can, I'll run a sander over it with some coarse paper to get the majority of the remaining glue off so it is flat again. Then once I make a replacement tread, I'll install it in it's place.

I'll go ahead and continue installing the treads above it.

I've accepted that I won't be able to nail the new replacement tread in the same fashion since the riser above it is already installed. I'll just weight it down heavily once I push/tap/coerce it into place. I'll make sure it's the same thickness so the new riser face that is installed can still help by keeping it from rising in the back.

What are your guys' thoughts on switching to regular liquid nails? It seems to not be as "moist" as this subfloor version and I think it'll keep any of my remaining treads from doing the same thing. I am also going to email the Liquid Nails company and see if they respond or have any helpful ideas.


Thanks again for the help anyone

[Jim Dwight]

It might have been the adhesive and it might have just been a board that wanted to cup. I did something similar to what you describe but I used 3/8 thick oak flooring. That allowed me to diagonally nail through the tongues of the boards - plus glue. You could also use 3/4 flooring but it changes the rise more - but if you raise all the threads plus the floor above the same amount then it is fine. If you don't want to use flooring, you could still make pieces 3 inches or so wide and tongue and groove them for installation like flooring. My last piece was a thicker nosing piece with a groove on the back to mate up with the flooring. It was held in place by three large finish nails and glue. My stairs worked well and looked good. I think they helped sell the house.

I would put a coat or two of finish on the back side of whatever solid wood you use. If you don't the side with finish will absorb much more slowly than the side without finish and that alone can cause cupping. The adhesives you are using are not like wood glue and don't depend on soaking into the wood to work. Especially if you hide some nails to help hold things (like by going to tongue and groove) they will stay put.

[Michael Zerance]

I would have removed the OSB and installed the tread right to the stringer. Also, finishing both sides would be good insurance. I use trim head screws at the back of the tread where they will be hidden by the riser. I think liquid nails should be fine but others will mention that the PL adhesive is a better choice.

[Chris Kiely]

I suspect it was the adhesive - especially if you used a lot (less can be more with that stuff)
But as mentioned above - finishing both sides is good practise all the time.

[Rantz Phelps]

Thanks for the replies guys. I emailed Liquid Nails and they got back to me yesterday. There response is below:

I know exactly what you are facing and no, you’re not crazy. Yes, the application of too much glue or even the wrong glue will most certainly cause warping in your Kiln dried treads. If you were using the LN-902 Subfloor, then I am glad to hear that this only occurred on the one tread as it very easily could have been all of them. That adhesive is not meant for treads as it has much to high of a water content. Yes, the LN-903 Heavy Duty is a better option, but you still have to be sure not to use too much there as well. Proper application would be 4 1” dots. 2 in front and 2 in back. The best choice is to go with the LN-950 Polyurethane as it will eliminate the warping issue.

Judging by his response, he's definitely agreeing with you guys that less is definitely more in this case. I just didn't want to have any "hollow" spots or have them come loose later and make popping or movement sounds. I'll definitely be more conservative.

So based on my experiences, the help here and his response, I went ahead and returned the 5 unused big tubes of the Liquid Nails "subfloor" adhesive to home depot. They don't carry the "polyurethane" version that he described. I found it online and it is rather pricey.

I didn't see any others that specifically said polyurethane formula when I was at HD last night, but I was rushing due to their closing soon. Thanks to the advice by Mike Z, I now see Loctite's PL line has polyurethane versions and HD carries that. So that's what I'm going to buy. Thanks guys!

So I'll add a thin coat of poly to the undersides and end grain of the treads. Then I'll use the Loctite PL adhesive instead. I'll still be liberal'ish with it so that it has plenty of coverage, but I'll be conservative for sure.

At this point, all of my parts are cut and made so I don't want to switch to a whole different install with taking of the OSB and going straight to the stringers. Because I'm also doing the flooring in the same thickness at the bottom and top landings, it won't cause a height variation change.

Thank you again guys!

I'll probably be back with flooring questions once I start milling all of it. I'm not making a ton, just enough for the bottom and top landings. I'll do a floating install with tongue & groove construction. The nosing leading to the stairs will be glued & nailed into place, but the flooring will just be glued together in the tongues & grooves. More on that later. I'm done for now!