I'm trying to level a room in preparation for the installation of
laminate flooring. The laminate flooring requires the subfloor to be
flat to 1/10" over 4'. The room is 17' x 12' and the walls are
supported by the foundation footing. There are two joists running
parallel to the 17' wall that are 4' apart. The joists are 4" x 6"
beams and the subfloor is 3/4" plywood.
The problem is the two joists are 1/4" lower than the walls. The 1/4"
drop is constant along the majority of the room and reduces a bit as
the joists approach the end of the room. The two joists are level with
each-other.
We have considered the following options to level the floor:
1. Lay 1/4" hardibacker between the joists down the length of the room
and screw them in place. Level remainder of the floors to the wall
using quicklevel cement.
2. Raise the joists by adding a 1/4" shim at the top of the piers.
We are thinking of going with option 1 because we aren't comfortable
performing option 2. We are worried we don't have the skills and we
may cause damage. In addition, we don't know where to get a jack to
lift the beam the 1/4".
Any suggestions on how to proceed with option 1? We ran a test run
with the leveling compound with mixed results. The leveler doesn't
appear be 1/4" thick (still drying).
The leveling compound should get you close enough. 1/10" is a tight
tolerance. Are using the thin rolls of foam on the existing floor?If
you are out 1/16" in an area, add extra strip of foam. You also can
level small areas with building paper, or even 30lb felt paper.The
joists are way undersized if your measurement is correct.If the area
underneath is a basement or crawlspace, consider adding a beam to cut
down the span.
mike
There are no support boards perpendicular to the joists. The condo is
30 years old and it does bounce a bit.
> >The room is 17' x 12' and the walls are
> > supported by the foundation footing. There are two joists running
> > parallel to the 17' wall that are 4' apart. The joists are 4" x 6"
> > beams and the subfloor is 3/4" plywood.
>
> Something is wrong with this picture. Is this really old
construction? Is
> there T&G boards perpendicular to the joists under the plywood? What
you are
> describing is a 44" joist span and that would make just 3/4" plywood
feel
> like a trampoline.
>
I understand it doesnt say level but 1/4" over 4 feet is greater than
the spec, right? I think this falloff would be fine if it was
constant accross the entire floor but it drops that much to the first
joist, the floor to the second joist is level, and then raises the 1/4"
again to the wall. I just looked at the spec again, it's 2 mm/m
(1/12" / 39"1/2).
> The flooring does *not* say level. It says flat. You may have to
tweek the
> flatness with a little floor leveling compound to make the flooring
happy,
> but that's it.
Thanks everyone for the help with leveling the floor. The leveler
seems to have done the trick and now I'm curious about the span of my
joists. What is a reasonable way of making the floor more secure? Can
I just secure the 3/4" plywood (subfloor) by spanning the joists with
2x4s? Do I need to add additional joists?
-- Craig
The levelquick took forever to dry cuz it's been raining. Now that
it's dry I can see some crystalline like structures on one pour that we
(mistakenly) feathered. The 1/8" thick cement at these edges lifted
off the subfloor. Walking on it has also caused a crack of more than
2' along the cement that is ~3/16 thick. Both the cracks and
separation occurred parallel to the joists.
Question is, should we lay the laminate over these problems? Re-pour
these areas? Start over with a new approach? Help!
Prometheus wrote:
> some construction adhesive down, then drive screws in about every 4
> inches or so (screws will help keep the floor from squeaking later on)
And they won't pop up. I did nails under vinyl tile. A LOT of nails. Like
three and half tons of nails. Six penny ring shanks, like all the books
say.
Damn things are popping like crazy. The floor is about ruined after only
two years.
I'll use screws next time.
--
Michael McIntyre ---- Silvan <[email protected]>
Linux fanatic, and certified Geek; registered Linux user #243621
http://www.geocities.com/Paris/Rue/5407/
http://rosegarden.sourceforge.net/tutorial/
On 29 Dec 2004 22:43:02 -0800, "craig" <[email protected]>
wrote:
>Thanks everyone for the help with leveling the floor. The leveler
>seems to have done the trick and now I'm curious about the span of my
>joists. What is a reasonable way of making the floor more secure? Can
>I just secure the 3/4" plywood (subfloor) by spanning the joists with
>2x4s? Do I need to add additional joists?
How long has the floor been there? Odds are if it's been around a
while, and hasn't collapsed, it's fine. You could throw another sheet
of 3/4" ply over the works if you're concerned about it. Just lay
some construction adhesive down, then drive screws in about every 4
inches or so (screws will help keep the floor from squeaking later on)
Aut inveniam viam aut faciam
"Stephen M" writes:
> Better yet, find a really striaght 4' piece of something, set it on the
> floor and eye-ball it.
What you are trying to create is what the boat builder calls a batten.
Get a piece of aluminum angle, say 3/4"x3/4"x1/16"x96".
Use the back 90 degree corner like a knife edge against the floor.
You will be able to pick up variations that are less than 1/64" with no
sweat.
The magic test is when you can't see daylight under the angle any more, you
have a fair surface.
SFWIW, it is exactly how my hull was faired out, a 3+ year process.
This surface is far from that critical, but the process is the same.
HTH
Lew
> I'm trying to level a room in preparation for the installation of
> laminate flooring. The laminate flooring requires the subfloor to be
> flat to 1/10" over 4'.
It probably is. Flat does not mean level. Their spec says if you put a 4'
straigt edge down in any place, what's the biggest gap. You are closer than
you think.
>The room is 17' x 12' and the walls are
> supported by the foundation footing. There are two joists running
> parallel to the 17' wall that are 4' apart. The joists are 4" x 6"
> beams and the subfloor is 3/4" plywood.
Something is wrong with this picture. Is this really old construction? Is
there T&G boards perpendicular to the joists under the plywood? What you are
describing is a 44" joist span and that would make just 3/4" plywood feel
like a trampoline.
> The problem is the two joists are 1/4" lower than the walls. The 1/4"
> drop is constant along the majority of the room and reduces a bit as
> the joists approach the end of the room. The two joists are level with
> each-other.
My house is 145 years old; sadly, out of level can be measured in unches in
some places.1/4" is *tiny* by old house standards.
> We have considered the following options to level the floor:
The flooring does *not* say level. It says flat. You may have to tweek the
flatness with a little floor leveling compound to make the flooring happy,
but that's it.
Then again if you want a level floor for some other reason go ahead and
build it up.
-Steve
> I understand it doesnt say level but 1/4" over 4 feet is greater than
> the spec, right? I think this falloff would be fine if it was
> constant accross the entire floor but it drops that much to the first
> joist, the floor to the second joist is level, and then raises the 1/4"
> again to the wall. I just looked at the spec again, it's 2 mm/m
> (1/12" / 39"1/2).
My arc geometry is little weak so lets approximate this using triangles. The
first 4' (and last, but it's identical) is the only one that we care about.
We know that the floor dips 1/4" over this 4'. Let's pretend that the floor
drops the entire 1/4" in the first 2' as a straight line, and then is level
with the joists from there. If we were to place our imaginary straight edge
from the wall to our first joist (4'), the biggest gap would be at the 2'
mark, where the floor goes from slanted to level. The "gap" between our
straight edge and the floor at that point would be exactly 1/8".
The dip in the floor is probably not a sharp angle like the approximation
above. A soft even curve would yield an even smaller gap, bringing you
pretty darned close to the flooring spec.
-Steve
> Thanks everyone for the help with leveling the floor. The leveler
> seems to have done the trick and now I'm curious about the span of my
> joists. What is a reasonable way of making the floor more secure? Can
> I just secure the 3/4" plywood (subfloor) by spanning the joists with
> 2x4s? Do I need to add additional joists?
If it was just 3/4" plywood you would KNOW it. It would be very spongy.
Maybe therre is a double layer in that sandwich. I doubt your floor is
"insecure" but it could be really spongy/springy.
I don't know if this will hlep but is you jump up and down of the floor with
all you weight and there is no real movement, you're fine. If it feels
spongy, more so between the joists than over them, then 2x4's will help. If
the floor is springy (try this over a joist but between piers) you would
need bigger joists (sister them) or more piers.
The 44" + only 3/4" plywood span just seems to weird to be true to me. I
think there is something else there. Before you install your floor, you
could drill a 3/4" hole in the floor in a out of the way spot, stick your
finger in there and verify the 3/4" plywood only assertion .
Steve
S
>
> -- Craig
>