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Underlayment for laminate

9K views 39 replies 6 participants last post by  epson 
#1 ·
hello

I just bought 300 sq ft of laminate at Lowes (Allen+Roth, 10mm, AC4 with 2mm padding underneath - "Russet Oak")
I will put it in my family room to replace the carpet (concrete slab)
But I noticed the floor was "cold", and I though it could be the right time to do something to improve floor insulation
I saw at Lowes some 1/2" 4x8 extruded foam boards (green)
I was thinking about laying down that foam, plus some plywood or OSB on top of it
What do you think? Does it make sense?
How should I attached the foam on the concrete? And the wood on the foam?
Thanks
 
#3 ·
Liquid nail to attach the foam to the slab or the the plywood to the foam, or both?
and other than that, what do you think about the idea?
At Lowes, they said I should call Allen+Roth to make sure it won't void the warranty
But with some OSB or Plywood over the foam, I don't see how it could be too flexible to damage the groove and tongue system !!!
By the way, what should be the thickness of the wood layer?
 
#4 ·
You can use it on both. But they do make an adhesive for flooring to be applied on the subfloor and then applying the flooring. It is always best to call the manufacture and ask them on how you intend to apply the flooring and if it would void the warranty just to be on the safe side. Never hurts to ask… check out the link: http://www.armstrong.com/commflooringna/adhesives.html

subfloor should be 5/8''
 
#5 ·
How do plan on finishing out where it meets the other floor?
Laminite need to float, so any transition stips would need to be under cut to allow them it to move.
 
#8 ·
Yes, that's a good point
Well, actually when I realized they didn't know about my solution I suggested I should call the manufacturer to verify the warranty and they said "yes, you should" when they should have said "No need, Allen+Roth is us and we can tell you yes or no right away"
I don't know what I'm going to do.....I would like to do it right, but it's going to require more money for that sub-floor (300 sq ft of foam and plywood)
On top of that, there will a piano in 1 spot, and that one is very heavy !!!
 
#11 ·
OK, I removed the carpet and the tackstrips
1) I noticed there was a gap between the baseboard and the floor, and I could feel some cold air....I was thinking to use some spray foam to seal that gap all around. Which one should I use: the one for windows that doesn't expand too much, or the regular one?
2) When I removed the nails from the tackstrips, the concrete was cracking (size of a quarter or sometimes a little bit larger, and 3 or 4 millimeters deep)
Should I patch those with concrete repair mix?
 
#12 ·
The reason the baseboard is above the floor is when the carpenter installed it he compensated for either carpeting or wood floors were going to be installed later. You can either remove the baseboard and lower it after you installed your laminate or install a ¼ round to cover the gap. As per the concrete cracking, yes you should fill in all the divots and make smooth as any inconsistency will show.
 
#13 ·
OK,I filled up the gap with PU foam (I tried both, the one for windows and the "great stuff" - I do prefer the last one)
Will have to cut it tomorrow, patch the holes and will verify the floor is flat
I guess I will start laying down the laminate by Saturday
Since the tongue must be cut for the 1st row against the wall, I will have to buy a table saw......
 
#14 ·
Hello

I am laying down the laminate
My room's length is 230.5", and plank's length is 50 3/4"
I thought I will start with a full plank, and cut the last one and start the 2nd row with what is left form that cut
But if I do that, the last piece of the 1st row would only be ~5"
So I guess I will have to cut the 1st plank to start
What should be the length of that 1st plank to minimize the waste?
Should I manage to have the 1 st and last plank of the 1st row the same length?
And how should I do for the other rows, since I will have to stagger each row by 12" (manufacturer recommendation), knowing the shortest plank should not be less than 16"....
 
#15 · (Edited)
OK, I figured it out, and I don't have too much waste

One problem though: I am almost done (80%) and I have a "springy" area..:furious:
I can remove some planks to access that spot (Swiftlock system, pretty easy to disassemble), and try to put a kind of shim (thin hard material - ~1/10" thickness - the area looks like a circle, approx 2 or 3 feet diameter) between the moisture barrier and the laminate
Worst case scenario, I would have to remove the moisture barrier and put a patch of cement (with self leveling mix?)...But this would be a pain in the butt !!!!
What do you think?

Last option: I leave it as it is, finish it up, put the shoe molding and live with that "spongy" spot...hoping there won't be any damage in the long term
 
#16 ·
Where is the springy area? Is it along a wall, in the middle, etc......

I had the same situation when I installed some Laminate recently in my own house And the biggest spring was in a couple corners. Normally I would want to do it right but this room does not see too much use so I left it be. If you step directly in the corner it drops a good amount but it is not often that happens.

If it is an area of traffic I would do it right and level it out.
 
#17 ·
It's not in a corner, more in the center of the room (not exactly the center though...)
It's the family room, and we want to make it a TV room....I would say traffic will not be too high
Some pieces of furniture may put "pressure" on it, then it won't move anymore....Not sure
 
#18 ·
Well, I think I will remove the laminate already installed and I will use some self-leveling mix to patch the lowest areas....1 bag should be enough and I will prepare some mix by smaller portions (not the whole bag in 1 shot)
It sucks, but I don't like the way it is right now!!!

By the way, where can I find a long (6 or 7 feet) aluminum rule to apply those patches? I didn't find any at HD.....
 
#21 · (Edited)
Let’s say I want to make a wood sub-floor based on sleepers + OSB boards
Sleepers being attached to the slab with Tapcon screws, and OSB glued and screws onto the sleepers
Sleepers every 2 feet with some foam in between….
I was thinking to use 1” x 4” sleepers (2 x 4 will be too high)
1) Is it OK to go with 1 x 4?
2) Should I use pressure-treated or regular white pine boards?
3) Do I need the grooved and tongued OSB 4 x 8, or can I go with squared edge as long as there are sleepers under each edge?
4) What shouldbe the minimum thickness of the OSB?

Thanks
 
#31 ·
1) Do I need to leave a gap (1/4") between the walls and the plywood? You should leave room for expansion.
2) Do I need to leave a gap between each plywood board (knowing they will be glued and screwed on the sleepers) you do not need to
3) Is groove/tongue boards mandatory or not?
No it is not. Minimum thickness of ply wood should be ¾”
 
#35 ·
Back to my laminate: I will have to install shoe molding (3/4" x 3/4" I guess)
I am planning to glue them down on the baseboard, but I will have to use some nails as well
I bought at Thanksgiving an Evolv compressor (pancake 3 gal) that included a 2" brad nailer gun
First time I will use an air nailer
Is it OK to use for shoe molding?
 
#38 ·
Ooops......sorry, being French in North America, I am learning all the new technical terms
I thought shoe molding was quarter round. Anyway, i left the baseboard and will need molding (shoe mold or quarter round) to hide the expansion gap
Once applied, I will probably caulk to have a perfect joint between the baseboard and the molding, and then repaint (this is what I did in my house in France many years ago, and was very pleased with the result)
 
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