Karndean Glue Down - dents from furniture, gaps, blotches, telegraphing!

Discussion in 'Vinyl Flooring Q&A' started by JHans, Dec 1, 2017.

  1. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    One thing about the end gaps of vinyl. The size of the piece, say it’s 6” x 36”. If it shrinks equally you would visually see the collective difference in one joint on the 36” length, but not so easy with that distance divided across 6 length joints. So the end joint gap has only moved half of the full width of gap, adjacent piece down the line shrunk the other half.

    Plywood joints are very tricky, to me it’s a gamble and we always tried to do everything right to avoid any situation. Could be the same situation as the plank example, the 8 ft length moves twice as much as 4 ft width. Also bright light floor level across length joints may show. The plank direction/texture can mask the length joint telegraphing. Spot beam lighting amplifies the end joints, there are many issues with lighting and what it focuses/draws attention to.

    I was told/have read that adhesive is not accountable to prevent product from shrinking. It has done that when manufacturers changed formulas to reduce the problems but it’s the actual formula in plank that causes it to reduce in size.
    Last edited: Dec 4, 2017
  2. Chris 45

    Chris 45 Director of P.R. on some deserted island. I Support TFP

    The gaps between the underlayment sheets and fixed walls is necessary for the same reason a lot of these new sheet vinyls require a gap: the house itself expands and contracts seasonally. You don’t want gaps between the underlayment sheets themselves. Just like a hardwood floor, you don’t want gaps between the sheets themselves because then those get filled with patch which will not expand and contract like the wood will. The underlayment grows, now you have a sunken valley and if it shrinks you have a ridge.

    Moisture readings should have been taken on the plywood floor that the 5/8 was laid over as well as readings taken on the 5/8 itself. Since you have access to the plywood underneath via the basement, readings of that would be helpful as well. You would at least know what layer of what had what latent moisture hanging around in it just waiting to move around and equalibriate just like moisture in a concrete slab will do. Too high of a moisture reading in one of the layers and things will change as that product acclimated to its new environment. The new layer will equalize to where the other layers are. Furthermore, just because the current existing layers of plywood have been down for some time doesn’t necessarily mean that they have an acceptable moisture reading. I get elevated moisture reading all the time even though the house I’m supposed to be working in has a more than comfortable climate controlled environment.

    Many box stores or even lumber yards don’t store their wood with as much care as say a floor covering supply warehouse would. Indoors in a climate controlled environment. I’ve seen plywood stored outside under cover, but still outside. What was the MC of your underlayment at the time of installation? Was it high? Then you installed it where it is now actively drying, and shrinking, then it got exposed to a bunch of moisture via the adhesive then capped over with the LVP which locked in that moisture? Or maybe the 5/8 was dry and what you installed it over has elevated readings. Same problem but in reverse.
  3. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    That’s my take as well. The moisture is supposed to be matched within 2% before being installed. Acclimating the sheets should be spaced so air can get in between.
  4. JHans

    JHans Well-Known Member

    I do not know the moisture reading of the underlayment. But the installer tested it two weeks before install, and then day of install, And they said it was good. They said a lot of times they have to postpone jobs because it's not low enough moisture. But ours was good. Like I said before I ordered a moisture meter and I will do the testing on Tuesday of all three layers of our plywood. The installer only tested the top underlayment. I want to get to the bottom of this moisture issue!

    We also are going to cut out a cross-section of one of the themes that has sunken to see if you can see it in the cross section. Hopefully we get that done tonight.
  5. JHans

    JHans Well-Known Member

    Also, when they pulled up the planks to fix the sunken seam the first time, the patch was not cracked at all. If the plywood was moving in any direction wouldn't the patch crack?
  6. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    One coat of patch usually ends up concave. It mostly always needs 2 coats. Is there a gully that the adhesive filled? That is an indicator that they glued over The dip in joint.
    Last edited: Dec 4, 2017
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  7. Jon Scanlan

    Jon Scanlan That Kiwi Charter Member I Support TFP Senior Member

    Chris you would end up replacing every vinyl job you do in New Zealand as customers will not except any gaps around the walls :)
    We cut the vinyl neatly into the skirting boards. Any gaps and it gets replaced

    JHans the acrylic glue is spread over the whole floor which means inducing a lot of moisture over the whole floor area
    New Zealand has an average RH of about 79% which is blowing under houses with timber subfloors. One could sand a T&G timber floor flat and 3 months later you could see every floor board through the vinyl. Since the introduction of these plastic backed vinyls I have become vary aware of what moisture from glue and our Relative Humidity can do to timber underlayment sheets. I am very careful about placements of the underlayment sheets to try and avoid line of site joins, making sure the sheets are butted tight together, etc, etc
    With the old asbestos backed vinyls the vinyl seemed to hide the underlayment joins as the vinyl seemed to compress into themselves over the underlayment joins unlike these new plastic type backed vinyls. It was a real learning curve for us but we have it sorted fairly well out now
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  8. Chris 45

    Chris 45 Director of P.R. on some deserted island. I Support TFP

    @Jon Scanlan so do you guys have different vinyls down under? I get the cutting tight and even patterning the vinyl when necessary but what happens when the vinyl manufacture calls for 1/8” to 1/4” gap. Up here I would have just voided the warranty which means I then own any potential problems that may arise.

    The felt backed vinyls could be cut tight all day long. Not these new fiberglass jobbies.
  9. Jon Scanlan

    Jon Scanlan That Kiwi Charter Member I Support TFP Senior Member

    Chris we get all of those IVC vinyls down here, I actually think they arrived here in a big way before you guys got them. Everything is imported here which could be the reason whereas you guys still have manufacturing plants
    I think the last time I looked at IVC site they now say for a full spread tight is good, loose lay, perimeter glue is where the gap comes in. Also we use arcylic glue not your releasable ones
    These fibreglass/plastic backed vinyls were like having to learn again as they will not do what the old domestic vinyls would do. Try coving these plastic backed vinyls over a wavey floor, just about have to pleat them to follow the waves
  10. JHans

    JHans Well-Known Member

    How would I be able to tell if the adhesive filled?
    Unfortunately we can't cut a cross section where we wanted (to look at the sunken seam). So I'm not sure how to tell if it is a valley that the adhesive filled.

    Getting my moisture meter tomorrow and will post the results.

    We had a ton of rain today and it was very damp. The basement humidity got up to 56%. Hopefully with the moisture levels of the three layers of plywood we can determine if it is or isn't a moisture issue.

    Karndean said they'd have the results of the testing to us this week.
  11. Jon Scanlan

    Jon Scanlan That Kiwi Charter Member I Support TFP Senior Member

    JHans would it be possible to take a reasonably close up sideways photo of the seam showing the Karndean plank which has sunk?
    Do you think its the actual size of the gap between the ply joints?
    I find it hard to understand a noticeable hollow with a small gap
    An upwards ridge I can understand
    I know its very hard to take photos of vinyl floors to get rid of reflections
  12. Grant H

    Grant H I'd rather be patting my dog.

    Would like to see that myself. A 3mm fairly rigid plank would need a hell of a void under it to "sink".
  13. Incognito

    Incognito No more Mr. Nice Guy! I Support TFP Senior Member

    Reading this from the beginning I believe they allowed a gap between the plywood seams of a quarter (US $0.25)
    thickness of a quarter> - Google Search
    Then ONE coat of Ardex Feather Finish.

    It's near impossible to fill that in one pass. If you take the time to compress it into the gap it actually pushes back and creates a small bump which can be wiped down before it hardens---------but that's a 2nd pass.
  14. Incognito

    Incognito No more Mr. Nice Guy! I Support TFP Senior Member

    Some of the planks we use are relatively shiny and smooth allowing virtually 100% telegraphing of substrate texture. A grain of fine silica sand will look like Mount Vesuvius under the vinyl and EVENTUALLY given normal traffic and unfavorable lighting everything shows through.
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  15. JHans

    JHans Well-Known Member

    I agree that the sunken area is much better than the coinnsixe gap we left, so it's hard for me to understand why it would look like that too.
    I will try for a close up pic.
  16. JHans

    JHans Well-Known Member

    Moisture readings -
    1st layer subfloor (original subfloor) 1/2" - 7.5-8.1%
    2nd layer subfloor 1/2" CDX - 7.8-8.2%
    Underlayment 5/8" BCX UL - 7.9-9.2%

    I cannot get a good close up pic of sunken areas, unfortunately.
    Please let me know what you think of the readings.
  17. JHans

    JHans Well-Known Member

    Anyone any thoughts on the moisture readings?
  18. SteveG

    SteveG Pro Member

    Hey - I'm late to the party - but back to the underlayment (which seems to be at issue here)

    Karndean states the following:

    (emphasis mine)
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  19. Chris 45

    Chris 45 Director of P.R. on some deserted island. I Support TFP

    Those numbers by themselves don’t seem crazy. Now if we had prior readings, such as before and during the installation, we could track what is happening. I’m wondering if some of your furniture indentations might be related to any voids in the plywood. Here’s a couple voids I discovered too late in my $40 a sheet plywood.

  20. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    I’m not sure of any guarantees listed about the inner layers of plywood.

    Attached Files:


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