Hi All,

I'm a General Contractor, never installed hardwoods before, and am currently putting 700 sf of prefinished 3/4" x 2.25" oak in my own place. Part of the project is a stairway and I'm using stair bullnose moulding and flooring boards for the treads/risers. It is a ways to the nearest flooring store so I purchased urethane adhesive (Roberts R1509) at Home Depot ($129 for 4 gallons). It says it is specifically rated for 3/4 hardwood/bamboo. Anyway, I installed the first 3 treads this afternoon and it looks to me like the urethane is expanding as it cures. It is not much but it is enough to cause a little buckling and some oozing from underneath the bullnose.

I'm wondering if this is typical and how it can be prevented. I really don't want to flash the stuff off because I can't imagine setting the boards in adhesive, pulling them, and resetting them without making a huge mess. I trowelled the urethane per the manufacturers instructions with a 1/4 x 1/4 x 1/4 trowel and set the boards immediately.

Any help would be greatly appreciated!

Thanks,

SteveW

When your troweling the substrate should be clearly visable where the teeth hit. Otherwise your troweling wrong and leaving to much adhesive. I think this job is clearly out of your comfort zone for a GC.

I'm pretty sure I'm not putting too much down. I do a lot of tile work and if anything I'm not leaving enough for the trowell notch size.

Have you heard of expansion problems with these urethane adhesives?

Steve

I agree with Stephen...And your using too much adhesive. Adhesive doesn't "ooze" unless your spreading it on too heavy. If your seeing excessive movement of the wood it's probably from the wood hydraulicing..from trowelling out a pool of adhesive. Adhesive expansion isn't gonna happen. And not even a valid theory on a section the size of a tred.

I just installed some Mannington engineered flooring with Robert's R1509. The glue expanded for me, even though I used the recommended trowel size. And I used a smaller trowel size just to be sure I wasn't applying too much mastic.

The glue expanded for me. I let the glue that expanded out between my flooring cure, then I cut a cross section of the excess glue. I clearly see air pockets, like pizza dough or gorilla glue.

I've used Mannington's Ultraspread mastic so I have experience with another urethane based, 0.0 VOC mastic. That stuff didn't expand. It laid down nicely, almost self-leveling.

Ok well lets review. The new all in one adhesives give a thicker application of glue to produce a better all in one vapor retarder/adhesive membrane. Those will ooze through the joints if you work on them or walk on them. Thats just the way gluing wood works.

If your going for the all in one system, stay off of it untill it sets. I have never had much of a problem with ooze between the joints using the recommended trowel for basic gluedown jobs. Even when stepping it up a notch to attain 95% coverage. I never get the highest suggested coverage manufacturers claim with their adhesives and recommended trowels. I always figure the lowest coverage which is usually 30 sqft per gallon.

Not so sure what you mean by expanded? After application, if you pull a plank you should not see trowell lines. It should even out as a flat layer of adhesive.

Roberts 1509, wow what a mess i have a 400 foot 3/4 inch glue down gone south about 2 months ago, i started out using a 1/4 by 1/4 by 1/4 inch trowel per manufacturers recommendations
the adhesive was oozing up through the joints during the curing process.......................so i switched to a 1/4 inch V notch.........same thing it was oozing up during the curing process then after about a week the whole job looked like a roller coaster..........WTF. inspectors came out and said immediatly that had i not told him it was a glue down he would have thought it was a floating floor......thats how spungy it felt, we opened up the floor and scraped off some adhesive and could literally pinch it in your fingers thats how spungy it was "never heard of an adhesive doing that" this adhesive is a complete fail i will never use it again, and of coarse Roberts sent out their own inspector and he ruled it installer error as they always do, he didnt even take in to consideration that the adhesive could be pinched in your fingers, the customers chief complaint was the spongy feel all bad area,s could be fixed but its getting replaced because of the spongy feel to the floor and Roberts is denying any responsibility I have never seen an adhesive act like that, that stuff is a joke and everyone is getting technical about it avoiding the simple fact that it failed and there isnt ANY installer error involved, IT FELT LIKE A FLOATING FLOOR are you kidding me.

Depending on what type of flooring was used there should still be an evenly thick l layer of adhesive spread that holds everything in place. Some types of engineered flooring does not have channels on the bottom so there would be excess adhesive since the channel can be filled and excess would not have anywhere to go except to fill the area where the pieces go together.
The adhesive has not failed just because it may still be flexible after it has cured.
It needs to be flexible in case the flooring develops expansion or contraction issues over the heating season which can change the size of each piece of flooring in width.
Sorry that you had problems. You may have had better luck with a smaller notch on the trowel.

its the flexibility of that adhesive the customer is complaining about. personally i think the adhesive didnt cure properly, as far as the adhesion it worked really well it was quite difficult to pull some planks off the floor with inspectors present as noted in the inspectors report, we cant get Roberts to give us any characteristics of that adhesive which is the chief complaint, its not listed anywhere on the bucket or in any literature, i have a picture of this crap actually bubbling up through one of the joints 30 minutes after that section of the floor was installed..........an actual Bubble about an inch in size, never seen anything like it,........Installer error what a joke

anyone walking on this floor theyre initial response is WTF, the fail is soooo obvious its rediculous yet roberts is getting tecnical in order to claim installer error, never have i seen an adhesive do this and neither has any installation companies or persons ive spoken to, the first inspection which i commissioned was all about the spongy feel of the floor the second inspection which roberts commissioned was all about installation error, 2 different opinions, i had a roberts adhesive go bad about 4 years ago........well it didnt go bad it was bad out of the bucket, it had liquified............you could pour it on the floor and it self leveled immediatly wouldnt even hold a trowel mark, what a joke i told my bosses if i ever see roberts 1509 or 1530 on a job again im walking, after the initial inspection when chatting outside the inspector told me he couldnt claim adhesive failure because he had no technical data to back it up, in other words roberts wouldnt give him any adhesive characteristics, he strongly agreed with my assessment of never using it again

what i really want to do is get the people at roberts "the ones who are claiming installation error" to stand on this floor and ask them if they would want this in they're house, would love to see them try to BS they're way out of that one, this one is so obvious its stupid, we have shops in tucson,Phoenix and in Utah we install for Home Depot not alot of glue downs these days But Roberts 1509 is going on the "do not use" list.

the inspectors i used were paid up front by cashiers check to ensure impartiality.

paggeau,

Well the 1509 is not the best adhesive in the world.

I use a 1/4 x 1/4 inch trowel all the time with Sikabond T21. That said yes you can get squeeze out. However rolling and weighting the floor down is definitely something I do all the time even with engineered. Installing a solid is even worse as any bowed planks/strips will lift the floor out of the glue, hence a floating floor now. Solid planks/strip is much stronger than any engineered stick of wood.

Tjat said using a smaller notched trowel is not going to help at all. Coverage should be in the 95% - 100% range especially for solid. Now if its over concrete thats even more of a challenge for solid.

I would prolly rule the same way if you had me inspect it.

You should prolly read this about elasticity of hardwood flooring adhesive. http://zaf.sika.com/dms/getdocument.get ... floors.pdf

Stephan
thanks for the comments however keep in mind this stuff can be pinched flat between your fingers, adhesion was not the issue here it was actually quite difficult to open up the floor and wouldn't want to be the one ripping it out, the real issue here and chief complaint by the customer is the spongy feel to the floor, they were not informed of the possibility of this and had i known it could be like this i would have never started "they have got to be kidding right". No wonder Big D Tucson quit carrying they're stuff along time ago. Pergo? ho ho the main office in Phoenix told us to never call them for inspections anymore..................Why because it useless they will automatically call it Installer Error even in the face of damming evidence, first calls to QEP/Roberts they were immediately taking a defensive stance......haven't even heard the evidence yet, roberts adhesives are on the "do not use" list..........ever.
Im pretty Livid over this crap can you tell this on is in there face and they are still saying installer error.

Stephan
i have pictures of this adhesive that i cut from my trowel it has a huge air/gas pocket and its full of microbubbles as well, tried to upload them here but unable to do so.

patrick