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  1. #1
    Join Date
    Jun 2011
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    Unhappy Popping Drywall Nails - Suggestions Please

    I recently moved into a 1960s built home (Silver Spring, MD). I see that nails are popping out from walls and ceiling throughout the home. A small bulge appears and in weeks, it cracks open, exposing nail head. I used a punch, drove them in (just a tap). Nails appear to be very lose in their holes.

    I hear random(5-15 per 24hrs) noises all the time, more if I change thermostat setting (say to 68 from 73 or hot day to cold night). Noises are like a snap/cracking whip or like when you try to remove old, stuck nail using claw hammer from wood or like expansion/contraction sounds of office buildings with large glass & aluminum side-walls.

    I see attic insulation is weak (fiber glass, blown in, has compressed/settled to about 1.5 - 2 inches, bald at places) & not ventilated well, gets super hot inside.

    I am inclined to think that temp variation, noises & nails popping are connected.

    I am thinking of using drywall screws every where, options are:
    1. Drive popped nails back in, put a new drywall screw, like 2" from nail.
    2. Remove nail, as they pop, drive a matching sized screw into same hole.

    I wish to have all problems solved...
    any suggestions much appreciated, thanks

  2. #2
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    Default Re: Popping Drywall Nails - Suggestions Please

    This is quite common when nails are used instead of screws. Optimally, you'd want to pull the old nails as they pop, then 2" above and below the old hole drive a new drywall screw.

    You didn't mention wall texture, so we'll skip that part for now.

    You can also try to push on the drywall with your hands, sort of lean into it, as to make more nail pops appear and speed the process. OR you can go hunting for them with a magnet, OR just wait until enough pop that it makes you want to fix a few at once.

  3. #3
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    Default Re: Popping Drywall Nails - Suggestions Please

    Dev:

    Putting a drywall screw in, say an inch from each popped nail head should permanently correct the problem.

    You don't need to know the rest:

    Drywall nail pops are caused by exactly the same thing that causes squeeking floors.

    When a tree is alive, both it's cell walls and cell interiors are full of a liquid that's similar to water. Once the tree is cut down, the moisture in the wood starts to evaporate. Initially, the moisture evaporates only from the cell interiors, and as long as the water evaporation is from the cell interiors, the wood simply gets lighter in weight.

    Once all the water has evaporated from the cell interiors, continued drying results in the moisture content of the wood dropping below something called the "fiber saturation point". At the fiber saturation point, all the water is evaporated from the cell interiors, and continued drying results in water evaporating from the wood cell walls. As the cell walls lose water to evaporation, they become thinner and stiffer. The result is a dimensional change in the wood, as well as a strengthening of the wood. Wet wood will bend more easily because the cell walls are softer.

    Now, as water evaporates from the cell walls, those cell walls become thinner, and that results in a dimensional change in the wood. In hardwoods, from a living tree condition to an oven dried condition, you can have up to 8 percent shrinkage in the wood. That's a full inch of thickness in a 2X12!

    Also, since it's only the cell walls that become thinner, and wood cells are shaped like long drinking straws closed off at their ends, the shrinkage across the wood grain is very much larger than it is along the wood grain. And that's simply because there are so many more cell walls as one travels across the wood grain than there are along the wood grain.

    Years ago when they built houses, the lumber was stored outside, and it got rained on. They would take wet studs or wet joists and nail them in, and cover with drywall and subflooring. As the wet joists dried out, a gap would gradually develop between the top of the joist and the underside of the subflooring. That gap was entirely the result of the wet wood drying out. However, when a person walked on that floor, the subflooring material would rub up and down on the nail, and it's the vibration of both the nail and the subflooring that causes floor squeeks in floors. To prevent this from happening, builders started to "glue and screw" subflooring down to the floor joists. The idea here is that the glue would hold the subflooring down to the top of the joist as the joist dried out and shrunk.

    Drywall nail pops are exactly the same thing happening to drywall nails originally driven into wet wall studs.

    However, now that the wall studs and ceiling joists in your house have fully dried out and have shrunk all they're gonna shrink, driving a drywall nail or screw in now will permanently fix the problem. That's because the wood is not going to shrink any more, and so there won't be any further gaps developing between the drywall and the dried studs or joists.

    Also, since the wood shrinks across it's grain, not only do wall studs get thinner, but the wood on both sides of the nail gets thinner too. The result is that the wood no longer presses on the nail shank with the same force it once did, and this is why your popped nails are loose. You can drive those nails in deeper, but they may come loose again. If it were my house, I'd just pull those old nails out and put a drywall screw in beside each one.

    Hope this helps.
    Last edited by Nestor; 06-30-2011 at 07:05 PM.

  4. #4
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    Default Re: Popping Drywall Nails - Suggestions Please

    Dev:

    I am inclined to think that temp variation, noises & nails popping are connected.
    A lack of understanding is fertile ground for conjecture. Understanding makes everything simple and obvious.

    One of the best resources on the internet when it comes to building construction and building materials is the University of Massachusettes at Amhurst Building and Construction Technology Program. You can find their web site here:

    http://bct.eco.umass.edu/

    If you wait for the page to fully load, and hover over the "Publications" link, you'll be offered to peruse their list of construction and wood related publications listed alphabetically by title or by author. One of the publications that's no longer available on their web site was published in 1996 by Dr. Stephen Smulski who has since quit teaching and started his own consulting company. That paper fully explains wood shrinkage in simple English and you can find a copy of it here:

    http://www.paintsource.net/pages/sol...ood_shrink.htm

    It's one paper that I believe EVERY newbie homeowner should read because understanding wood shrinkage is key to understanding a wide variety of problems that can occur in houses. If you read my previous post, then you've already got a good understanding of wood shrinkage, and should have no trouble reading the paper.

    (Smulski kinda goes overboard in the section entitled "Diagnosing Diagonal Cracks" when he starts hypothesizing that cracks around windows are caused by wood shrinkage and suggesting people use round windows, so read that part with a healthy dose of scepticism. You want to pay attention to the other parts that deal with wood shrinkage directly and how it manifests itself in squeeky floors and drywall nail pops.)
    Last edited by Nestor; 06-30-2011 at 07:52 PM.

  5. #5
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    Default Re: Popping Drywall Nails - Suggestions Please

    When wood shrinks around a wire nail, it gets tighter, not looser. Windsor chair makers know this and use green wood for the seats and dry wood for the turnings. The shrinking hole grips the tenons the same way it tightens around the nail. Ever tried pulling, Oh, 10,000 nails from a barn that was framed with green oak lumber? I did that job this spring. There's nothing tighter than a nail driven in green oak.

    You'll have to give this some thought, then explain rationally how a hole in green wood ends up bigger after the wood shrinks.
    Casey
    Remove not the ancient landmark, which your fathers have set.

  6. #6
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    Default Re: Popping Drywall Nails - Suggestions Please

    Quote Originally Posted by Sombreuil_mongrel View Post
    When wood shrinks around a wire nail, it gets tighter, not looser.
    No, it's the other way around. When wood dries it shrinks, and that includes the wood on both sides of the nail. As the wood on both sides of the nail shrinks, it no longer grips the nail with the same force it originally had.

    However, you have two opposing forces in play. If you drive a nail into wet wood, the shank of that nail can rust, and that rusting has the opposite effect. Not only will the shank of a rusted nail be rough to grip the hole better, but the rust itself takes up more space than the iron in that rust did.

    I've seen studs where a "bump" formed around each nail driven into the stud. That was because the rust that formed on the nail made the shank of the nail rough and the roughness of the nail surface held the wood in it's swollen position as it dried.
    Last edited by Nestor; 06-30-2011 at 08:27 PM.

  7. #7
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    Default Re: Popping Drywall Nails - Suggestions Please

    *** casey why werent you able to explain what causes drywall pops in a 15,000 word essay like nestor . you should be ashamed being a tradesman and explaining it so bluntly

    lol sorry couldnt resist
    fire up the saw and make some dust

  8. #8
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    Default Re: Popping Drywall Nails - Suggestions Please

    Let me keep it simple:

    When nails pop out, replace them with drywall screws, not exactly in the same location, but 2" away. Slowly but surely you will stop hearing those terrible noises.

    That's what I do, and it works.

  9. #9
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    Default Re: Popping Drywall Nails - Suggestions Please

    Didn't I say that already?

    If you can, ridge venting with continuous eave venting is optimal. Other venting systems lead to hot spots, which you may or may not care about.

  10. #10
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    Default Re: Popping Drywall Nails - Suggestions Please

    I find that lots of people in the southern USA try to increase the amount of attic ventilation to allow the hot air out of their attic in summer in an effort to help keep their house cooler.

    If that's the case here, ignore the rest of this post.

    Where I live, insufficient attic ventilation can result in an inch of frost forming on the underside of a roof over the course of a winter (and I saw a picture of one house with 3 inches of frost under it's roof). That frost causes no problems...until spring, when it melts and drips off the roof rafters onto the ceiling insulation below. Insulation works by keeping air stagnant and preventing convective currents that would otherwise form. Unfortunately, that also means that wet insulation takes forever to dry out because of the lack of air circulation through it, and wet insulation in contact with wood joist leads to wood rot. And, on top of it all, the vapour barrier below the insulation will help keep the ceiling dryer than it would otherwise be, and that diminishes the urgency of the problem in the eyes of the homeowner. So, you have a "perfect storm" of problems arising from insufficient ventilation that can do real serious damage to a house.

    The first thing to determine is whether or not you need more attic venting.

    Go into you attic on the coldest day of the year and look for frost or condensation anywhere on the underside of the roof sheathing. Look for dirty spots on the insulation cuz if there is any condensation forming airborne dust will stick to the wetness and it'll be deposited on the insulation by the dripping water. If you don't see any frost, condensaiton or dirty spots on the insulation, then check to see if you have any ice damming on your eves. If you don't see any of that either, then you don't need any more attic ventilation than you already have.

    Ridge vents with soffit vents are only THEORETICALLY optimal. They rely on the convection of warmer air out the ridge vent and colder make up air in the soffits to work as they're supposed to. However, you have as many dead calm days in the winter as you do in the summer, and MOST of the time there's some wind outside. That wind creates a higher pressure on one side of the house than the other and you get cold air coming in the soffit vents on one side of the attic and warmer air being pushed out the soffit vents on the other side of the attic. Just pop up to your attic for a smoke on any winter's day and you'll see that the smoke doesn't rise gracefully up to the ridge drawing cold air in behind it through the soffits. It gets swirled around in every direction at once by the air currents in the attic caused by wind coming in the soffit vents.

    My feeling is that the more holes you have in your attic that allow air in and out, but not water, the better. That's because not all of those holes will be working all the time. For example, where I live, it's common to have a foot or so of snow accumulate on your roof in the winter, and that pretty much renders a ridge vent useless. That's when you discover that you ALSO need gable vents. But, the gable vents will only be effective when the wind is blowing the right way. So, in my view, the more holes you got, the better. Once the warm air rises into your attic, it's of no more benefit to you, and it's better to get rid of it as fast as possible than to let moisture condense out of it.
    Last edited by Nestor; 07-01-2011 at 02:13 PM.

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