Staples Go Through Floor and Terminate in Air
staple length for fastening underlayment
Dear GBA friends,
I’m in a pretty irritating situation. I just had marmoleum flooring installed, and it looks fairly good. (I won’t get into the glue smears & streaks I had to scrub up, because they are coming off, using a forbo cleaner, so that’s a minor inconvenience.)
The serious concern I have is that the installer used inch and a half staples to fasten down the underlayment. The underlayment is 1/2 inch ac plywood. The subfloor is 3/4 inch plywood. Thus, the staples have exited the plywood. (Fun times vacuuming up thousands of wood splinters in my conditioned crawlspace.)
Pre-install, I asked the company about staple length and he said that the installer would know the correct fasteners and fastening schedule. But when the installer showed up, and I asked him what staples he had, he said inch and a half.
Of course the installer told me he knew what he was doing and he’s a professional. I had to go to work and I didn’t press the issue. I now wish I had. My local forbo tech told me that I was right, the staples should have been shorter. Having staples (in this case they were “divergent point staples” apparently) terminate in air is not ideal for holding power.
Do any of you have any experience with this? Will the staples “back out” of the underlayment, as the forbo tech suggested is possible? He said it was possible I’d see “pimples” as the staples backed out of the underlayment, creating bumps in the marmoleum. But how soon? How likely?
I feel sick about this. If the marmoleum needs to be torn up, and re-installed, it needs to happen now, not after I build custom cabinets and built-ins.
The marmoleum is throughout most of my house, not just in a small area.
No, I can’t just redo the flooring up to the cabinets, because the central idea was to run the marmoleum all the way to the walls, creating a clean open visual effect, with open shelves in some areas. I will not be installing pre-made box cabinets.
My crawlspace is conditioned-ish (that’s another project). The humidity in the crawlspace is holding steady (lately) around 71% (Just installed the monitor so don’t have a lot of data on that.) Will corrosion (of the staple tips) be a secondary concern?
I’m in Western Oregon, hot dry summers, milder winters with occasional deep cold snaps.
I’m waiting to hear back what solution the installer suggests, but would like to be equipped with as much information as possible.
I did write a long email to the installing company (cc’ed to the forbo regional tech/representative) detailing my entire saga.
Should I insist they reinstall? Am I overreacting and it will be NBD?
Thank you for any insights you can provide!
Paula
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Replies
I'm trying to think of a reason having the staples penetrate the subfloor would be a problem, and I'm drawing a blank.
From my understanding of divergent point staples the extra hold is from the points forcing the legs to go to somewhat opposing directions as the legs go through the material at the time of being stapled. The points don't really do anything after that, so I don't see an issue with the staples going all the way through affecting their holding strength. In fact, with roofing nails you have to go all the way through.
I could see this being an issue if the staple points were coming through a finished surface, but this is a crawl space, correct? It's not like you're going to crawl down there with a hammer and start tapping these staples up which is the only way I can imagine they'd telegraph back through the flooring.
I'm not a marmoleum expert, so maybe there is something seriously wrong here, but I'm not seeing a major issue here.
I'm thinking of roof code.
If the sheathing is 3/4, the nail has to at MIN be 3/4 into the sheath. If the sheathing is less than 3/4, the nail has to penetrate past the sheathing.
If you read that, it means penetrating past the sheathing on roofing nails is always better than the one time minimum in code.
I think where you could be right is divergent point staples flare out to create greater hold? I don't know if that dependent on being 100% embedded or occurs by the initial penetration. If the latter, I think you can breath easier?
Paula,
Staple length aside - and I agree with the other posters it is pretty inconsequential - the underlayment should primarily be held down by adhesive. As long as it was well glued, the fasteners don't matter much.
You know, that said, if the manufacturer does come back with it's not right, yeah I would peruse that it was installed out of spec.
We're guessing, they tested.
Ryan_SLC,
forbo itself doesn't seem to have underlayment specs beyond this:
"Marmoleum 07-2022Installation Guidance Note:
Marmoleum sheet
General Advice
The appearance, performance and durability of the installed floorcovering will be determined to a large extent by the quality of the prepared subfloor and the conditions in which they are laid.
The installation of Marmoleum Sheet should be carried out in accordance with the national code of practice for the installation of resilient floor coverings if applicable. Areas to receive flooring should be clean, free from other trades, fully enclosed and weather tight. Subfloors should be clean, smooth, sound and permanently dry
Thank you all. I feel relieved by your replies. I documented my concerns, and the forbo regional tech is going to go take a look at it.
I will give you an update after Wednesday.
Did you hear back?
If Forbo has a specific requirement on the underlayment and its fasteners, they need to publish those. As is, with the generic info they publish, there is ALOT open to interpretation.
The reality is your floor is installed and you are probably not going to get anywhere with the installers. Yes, divergent point staples are often spec'd to not fully penetrate through the subfloor. But if you really want to get technical, the installer should follow the APA (American Plywood Association) fastener schedule for smooth face underlayment, and that calls for nails, not staples.
Hi All,
I apologize for the lack of updates.
1) I still don't know if the plywood was fastened down with adhesive.
2) Most people I have talked to are not concerned about the staples backing out. It's been a month, and I haven't seen anything that looks like a lot of staples.
I have seen a couple of spots that look like bumps - hard to tell if there was a small particle trapped under the marmoleum, but I guess it COULD be a staple backing out.
3) The Forbo Rep said that what would cause fasteners to back out of wood is floor movement: If the floor framing was not to code and the vibrations of lots of walking was significant. My floor is well-framed, meets or exceeds code.
4) The company owner and project manager came out to look at the job, see the staples sticking out of subfloor, and look at the job. We agreed that overall the marmoleum was installed well and looks good. It feels like a shame to tear it up. I am also annoyed to wait a couple of months to see if staples start backing out. I want to get moving on building cabinets and installing built-ins now.
5) At the roll ends the marmoleum didn't stay glued down in some places, resulting in an air bubble that smooshes down when pushed. I am having the installer repair those by injecting glue through the marmoleum into the air bubble and then place weights (blocks of wood) to keep the marmoleum down while glue cures.
6) I intend to ask the company for either a) assurance in writing that they will fix this if their installation fails (lifetime of product) or else give me a partial refund for the cost of the job. This is based on the recommendation of a friend who has more experience than I working with contractors. However, I don't want to do harm to the relationship with this company, as they are the best in the area, and I would need their help in the event I need major repairs.
7) The Forbo regional tech said that ASTM 1482 states that the fastener/staple shouldn't exit the plywood. I tried to located ASTM 1482 but that document seems to be hard for me to access. Do any of you know how to access that text?
8) If anyone else is considering marmoleum, you may be interested to know that the flooring company initially said I didn't need any underlayment over the subfloor. I investigated further (talking to marmoleum tech rep) and ultimately went with 1/2 inch ac plywood, which isn't even as fancy as the marmoleum tech was recommending. He had some sort of hardwood ultra nice plywood in mind, but that seemed like overkill to me.
I have a whole other post in mind for you all regarding my conditioned crawlspace, but that is the marmoleum update for now. The installer will be coming out Thursday 12/21 to fix the air bubbles, so I may have more information at that time.
Thank you all for listening and asking questions...
Paula
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Attaching a shot of how nice (generally) the space looks with the flooring. Color is Forbo Piano Otter. (Walls are unpainted gypsum plaster.)
Last 3 photos show the staples sticking out of subfloor. I cringe when I see the mildew stains on subfloor. I'm hopeful that they formed before I got the plastic down in the crawlspace, but I have a couple of mold test kits for pursuing the crawlspace health issue (next post).