Not really green related, but general construction.

Our main floor is not finished, and I noticed that our 3/4" advantech subfloor was nailed to the joists instead of screwed. I was able to look at construction pictures and evidence from underneath that there was construction adhesive used as well. However, I about tripped over a nail that is popping out. (this was built only 4 years ago).

My personal reaction is that it should have been screws in the first place. So now I am wondering if we should screw the subfloor before we finish the house this year? Or is it not necessary?

The time to do it would be now before we start our project this fall. Thanks.

What kind of nails - common or annular threaded nails?  Annular threaded nails do not back out very easily.  Almost as good as screws.  Maybe the one nail you saw was not driven deep enough.  I suggest you pull that one nail to determine which type it is.  If it is a common nail, then replace with screws.  By the way, a common nail will be easy to pull.

Posted By Alton on 03 Jul 2012 03:50 PM
What kind of nails - common or annular threaded nails?  Annular threaded nails do not back out very easily.  Almost as good as screws.  Maybe the one nail you saw was not driven deep enough.  I suggest you pull that one nail to determine which type it is.  If it is a common nail, then replace with screws.  By the way, a common nail will be easy to pull.

I agree. If the nails are common nails, then replace them with screws. I had that happen at a previous home I lived in. The subfloor nails popped and the floor would squeak like crazy when you walked on it. Better to do it NOW then later. When dealing with wood, I use screws almost 99% of the time. Wood expands and contracts so much that nails just back out over time.

it is possible that the framer did not have the air PSI high enough to set the nails, or was nailing too fast for the compressor to keep up.

When you guys say "replace them with screws", you don't mean pull out the nails and use screws instead, do you? Can't you just add the screws and have it be good?

If sufficient construction adhesive was used, you really don't need either nails or screws at this point after the adhesive has cured. Any nails that have worked their way up for whatever reason (likely due to not being fully seated to begin with or due to temperature changes causing thermal expansion and contraction of the decking) I would pull them out and replace them with a screw just for peace of mind. If the majority of the nails are fully seated and have remained flush with the subfloor surface after this length of time, I wouldn't mess with them.

As Holmes on Homes says, "glue and screw", especially if tile is being applied. Any movement in the subfloor can cause the tiles to move, crack and for the grout to break apart.

Posted By arkie6 on 04 Jul 2012 01:03 AM
If sufficient construction adhesive was used, you really don't need either nails or screws at this point after the adhesive has cured.

The code requires fastening

was the nail that backed out a miss? usually a nail, even common wouldn't back out unless midspan or at a point of max deflection. nails that miss and are snug against the side of joists will squeak and can back out over time.

we do a partial nail when setting subfloor in glue for speed sake, then finish the floor off with a senco duraspin stand up screw gun, after your done, go below the floor and pull any misses or partial splits and reset properly. the checking from below is important to you eliminate potential squeaks now versus 3 years later.

if a floor has full nails as yours does i do a 16" o.c. field screw and 8" o.c. edge pattern with the nails left in.

the nails or screws are just to hold the plywood down until the glue dries.
It becomes one assembly with good glue.   Try using some construction
adhesive to glue a couple of small blocks of wood together and then
try to separate them after it dries.    You'll destroy the wood if you
can even get it apart.


I screwed mine on an addition just because the dozens of squeaks on
the existing house were so annoying (and under hardwood floor that
I didn't want to mess with) and I wanted zero chance of a squeak.

Posted By allan-sf on 16 Jul 2012 12:05 AM

the nails or screws are just to hold the plywood down until the glue dries.
It becomes one assembly with good glue.   Try using some construction
adhesive to glue a couple of small blocks of wood together and then
try to separate them after it dries.    You'll destroy the wood if you
can even get it apart.


I screwed mine on an addition just because the dozens of squeaks on
the existing house were so annoying (and under hardwood floor that
I didn't want to mess with) and I wanted zero chance of a squeak.

NO!! the screws or nails are required by code , the glue is not

Chris,

We are not saying you can't or shouldn't use either nails or screws when installing subfloor. 

What we are saying is  that realistically they don't do much for you after the construction adhesive has cured, so don't sweat it if your framing crew used nails instead of screws.

Posted By arkie6 on 16 Jul 2012 07:27 AM
Chris,

We are not saying you can't or shouldn't use either nails or screws when installing subfloor. 

What we are saying is  that realistically they don't do much for you after the construction adhesive has cured, so don't sweat it if your framing crew used nails instead of screws.

We use nails as well to our metal joist framing, screws take too long to install and by the time they are all in the glue has already set.
It is important to get the plywood laying flat as soon as possible for a good bond.

Nails that seem to be popping are at the midspan, so i guess it would make sense that they've worked themselves loose. This area is supposed to get tile too, and even though according to the manuf. specs on this length of span for my i-joists for 16 o.c. is supposed to be L/480 and good for tile, this floor is very "bouncy". The can lights rattle when you walk on it. I am concerned that tile will crack.
Should I add some sort of blocking? how do you block I-joists? Granted, we don't have drywall ceiling in the basement yet, so not sure if that "adds" any sort of stiffness, or it that just means my ceiling drywall will crack.

Thanks for the tip on looking from below for the misses. There's plenty of them to see since we still don't have basement ceiling.

Thanks.

Posted By Boontucky-girl on 09 Aug 2012 11:26 PM
Nails that seem to be popping are at the midspan, so i guess it would make sense that they've worked themselves loose. This area is supposed to get tile too, and even though according to the manuf. specs on this length of span for my i-joists for 16 o.c. is supposed to be L/480 and good for tile, this floor is very "bouncy". The can lights rattle when you walk on it. I am concerned that tile will crack.
Should I add some sort of blocking? how do you block I-joists? Granted, we don't have drywall ceiling in the basement yet, so not sure if that "adds" any sort of stiffness, or it that just means my ceiling drywall will crack.

Thanks for the tip on looking from below for the misses. There's plenty of them to see since we still don't have basement ceiling.

Thanks.

It is normal in the rough frame stage to have some bounce in the floor, but after the walls are framed, drywalled and all the load is on the floor , the bounce should be done , are you sure you are not overspanned on the joists / or your supporting beam?

Posted By Boontucky-girl on 09 Aug 2012 11:26 PM
Nails that seem to be popping are at the midspan, so i guess it would make sense that they've worked themselves loose. This area is supposed to get tile too, and even though according to the manuf. specs on this length of span for my i-joists for 16 o.c. is supposed to be L/480 and good for tile, this floor is very "bouncy". The can lights rattle when you walk on it. I am concerned that tile will crack.
Should I add some sort of blocking? how do you block I-joists? Granted, we don't have drywall ceiling in the basement yet, so not sure if that "adds" any sort of stiffness, or it that just means my ceiling drywall will crack.

Thanks for the tip on looking from below for the misses. There's plenty of them to see since we still don't have basement ceiling.

Thanks.

Normally you use the same material for blocking. Code here effectively says blocking every 7 ft. It will stiffen it up a lot if you use it a bit more often. Drywall will help but I hate relying on it for that. The joist should be able to do the job.

Chris - walls are framed, but no drywall, no load yet. These are LPI-20 Plus I-joists. The tables I got from the manufacturer say for 40 psf live, 10 psf dead loads in a continuous I-joist, for an L/480 the max span to internal support is 21' for an 11 7/8" I-joist at 16" o.c. without web stiffeners and no blocking. This span is at 18' (the I-joists are 32' long continuous over a mid-span beam at 18' from one end).

Mike, when you say you use the same material for blocking, do you mean you use cut up I-joists for blocking? Would you hang those from hangers with filler behind hanger to the web? Would 2x4's in an X nailed to top and bottom flanges work? Or what else could I use for blocking.

The beam I mention above is directly below the middle of the 7' x 4' kitchen island. The fridge and some cabinets will end up in the middle of the 18' span on some of the I-joists, and planning tile over the whole 18' section. I am concerned that there's a lot of load on these and I'm wondering if blocking would be prudent? Or overkill?

Thanks.

You can gain a little info regarding floor performance here:
http://www.woodbywy.com/literature/TB-104.pdf

Thanks greentree. I read through that quickly, but seems like very good information.
I guess for peace of mind I could just add blocking under this floor since it will receive tile.

Posted By Boontucky-girl on 15 Aug 2012 11:03 AM
Chris - walls are framed, but no drywall, no load yet. These are LPI-20 Plus I-joists. The tables I got from the manufacturer say for 40 psf live, 10 psf dead loads in a continuous I-joist, for an L/480 the max span to internal support is 21' for an 11 7/8" I-joist at 16" o.c. without web stiffeners and no blocking. This span is at 18' (the I-joists are 32' long continuous over a mid-span beam at 18' from one end).

Mike, when you say you use the same material for blocking, do you mean you use cut up I-joists for blocking? Would you hang those from hangers with filler behind hanger to the web? Would 2x4's in an X nailed to top and bottom flanges work? Or what else could I use for blocking.

The beam I mention above is directly below the middle of the 7' x 4' kitchen island. The fridge and some cabinets will end up in the middle of the 18' span on some of the I-joists, and planning tile over the whole 18' section. I am concerned that there's a lot of load on these and I'm wondering if blocking would be prudent? Or overkill?

Thanks.

Most builders either toe nail the I-joists or do the 2x2s or 2x3s depending on what is around and what they want to run within the joist space. I don't think it is overkill at all.