How to Fix Ceiling Corner Cracks!
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- čas přidán 29. 08. 2024
- #trussuplift #ceilingcornercracks #wallcracksatceiling
What’s up with those ceiling-to-wall cracks that appear every winter? Caulk is just a temporary solution. What can you do? DIrtFarmerJay explains what is going on and what to do about it.
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We’ve noticed there are a couple of spots in our home that we can count on a gap forming every year when winter comes on. It only happens on a few wall-to-ceiling joints (also known as the “ceiling line”) on the top floor of our home. Caulk only provides a temporary cosmetic fix, then they’re back the following year.
What is going on? Truss uplift, that’s what! This is a common problem for homes situated in areas where cold winters with snowfall and late fall and early spring rains occur. The available moisture in the air will ultimately create uplift in the trusses that are used in modern framing approaches for dwellings. More on that in a bit.
It used to be that roofs were framed using a center ridge (supported at the gable ends) with rafters “leaned” against them, with separate ceiling rafters installed to resist spread on the outside walls, as well as to create the plane of framing members to affix the ceiling to.
Nowadays, these elements are tied into a component. A common triangular truss unit is set to a certain “pitch”, called out by rise and run. In the U.S., “rise” is how high the top chord rises in 12” of horizontal distance, known as “run.” In our example, a 5/12 truss will rise 5” for every 12” of horizontal “run.”
All the elements (top chord, bottom cord, webs, and so forth) are affixed with nailing plates. The truss is set on the perimeter walls of the structure and affixed, typically in distances between 16” and 24”.
One of the most used shapes for trusses is triangular. As you know, a triangle cannot change without either un-attaching one of the corners, breaking one of the members, or distorting the shape.
And, the last one is precisely what is happening when truss lift occurs. The bottom chord is typically buried in the insulation that is found at the bottom of the attic. So, that portion of the truss is dry, stable, and warmer than other portions of the truss. The webs and top chords are not insulated and readily absorb available humidity/moisture - so they grow slightly in length.
Because the truss is affixed at the outside bearing points on top of the perimeter wall, any growth in the length of the sections of the truss only has one place to go - to the apex of the truss. When this happens, the webs pull up the bottom chord, creating truss uplift.
This effect can be minimized during construction by not affixing the gypsum board to any truss bottom chord within 12” of any interior wall that connects to the ceiling. Also, using overhanging blocking on the top plate of the interior wall, and affixing the gypsum board there, will assure there is no gap that forms in the drywall at the corner.
If you are working to retrofit an already completed home, it’s a bit more complex, and you’ll need to determine if the annual gaps that form in the winter are worth the investment to fix. Simply filling the gap with caulk won’t really fix it, but it may make YOU feel better!
If you have a smooth or lightly finished “skip-trowel” ceiling, you can try locating the bottom chords/ceiling joists that are within 12” of the offending wall. Once you locate the screws or nails that are holding the drywall to the ceiling, you can remove them and patch and paint. This will allow the gypsum board to “float” more and minimize cracking. It’s not perfect, and it won’t work in every case, but if the annual truss uplift cracks are driving you crazy, then it could be worth a try!
There are not many people that know about truss uplift, but now YOU do. And when it comes to either framing correctly for new construction or a retro fix, you can JUST DO IT YOURSELF!
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8:23 I think you have this backwards. Cold winter air is dryer than than humid summers.
In winter, wood shrinks, and because of its grain structure, dimensional changes occurs across its width, not length.
Therefore, the top cord is narrowing, pulling the bottom cord up. If you know your geometry, you can understand how that slight narrowing is amplified by the diagonals of the webbing
Older homes didn’t experience this as much because attics were temperate - Less insulation, air leaks from below and leaky ducting. But as homes are made more efficient, there’s a more dramatic atmospheric difference between the attic and the conditioned space below.
This was an extremely educational video that helped me understand the changes I have been observing with my home. Thank you.
Glad it was helpful!
I found your explanation of trust uplift very informative, helpful and definitely explains why the separation is happening in my bathroom wall at ceiling joint. I was hoping you would show how to correct the issue. IF you have another video that shows the correcting process, please point me to the URL.
I have subscribed and look forward to your other coaching videos.
Thank you!
Glad it was helpful! The effects of truss uplift are better addressed during construction of the home. Obviously, you don't have that option. Here is some more detail I outlined in video's description:
"If you are working to retrofit an already completed home, it’s a bit more complex, and you’ll need to determine if the annual gaps that form in the winter are worth the investment to fix. Simply filling the gap with caulk won’t really fix it, but it may make YOU feel better!
If you have a smooth or lightly finished “skip-trowel” ceiling, you can try locating the bottom chords/ceiling joists that are within 12” of the offending wall. Once you locate the screws or nails that are holding the drywall to the ceiling, you can remove them and patch and paint. This will allow the gypsum board to “float” more and minimize cracking. It’s not perfect, and it won’t work in every case, but if the annual truss uplift cracks are driving you crazy, then it could be worth a try!"
Also, take a look again at the video beginning at about timestamp 11:25.
I hope this helps! Best, DFJ
I really enjoy your channel. Your advice is spot on and has helped me many times, you come across as honest and trustworthy. By the way the wall or corner trim in your house is stunning. Good work, craftsmanship and tasteful design. I’m definitely copying it in my home! SEMPER FI
Jeramiah - great to hear from you. Thanks for your kind comments! We've enjoyed doing the trimwork in our home and have some upcoming projects we'll feature. Thanks for being a part of our viewer family! Best, DFJ
Excellent video. The house I'm currently remodeling had a significant truss lift issue that the previous owner tried to cover with paneling and cove molding. The dry wall is nailed every four inches on the ceiling right up to the partition wall. I am using inexpensive small round magnets from Harbor Freight to locate the offending nails.
Blocking on top of the partition wall is essential but you should also allow the truss to float by not nailing the bottom cord to the top of the partition wall. Simpson makes an L shape truss clip that has a perpendicular slot in it. The clip is secured to the top of the partition and nailed loose in the center slot to the truss with a single nail. This holds the truss in place and allows it to float.. If you don't have clips on hand, you can drive a sinker into the partition wall on both sides of the truss but not in it. The trusses in the house I'm working on were toe nailed through the bottom cord with 12d sinkers and split over time. This addition was added over 50 years ago so this is likely an issue that developed over time.
Thanks for writing. What you describe is precisely the problem in many situations. Whereas the carpenter thought they were making everything more secure, they didn't take into account all the forces from different directions that would be applied to the structure as temperature and humidity changed. Thanks for the tips on the slotted clip as well as the method of using twin sinkers on both sides of the truss into the partition. Good stuff! Best, DFJ
@@DirtFarmerJay One of my subcontractors pointed out something I missed. Trusses usually require cross-bracing between the webs. This stiffens the trusses and allows them to move as a single unit. Bracing requirements are shipped with trusses and must be nailed according to the engineering specs to pass inspection..
Great explanation! Great video quality.
Wow. This is excellent! Dad was a rough framer and carpenter by hobby and I watched him and soaked up all he knew. This issue was NOT part of the education. So, if I were to see that issue occur it would cause a lot of anxiety and I'd be imagining all sorts of failing structure and costly repairs. LOL Really helpful illustration and information. Except for the pesky ceiling patching the remedy is easy.
Thanks, tues boomer! I appreciate you watching our video and then taking time to write. Best regards, DFJ
Thanks for the tips, always enjoy watching your channel.
Good to hear from you, Drew. Best, DFJ
@@DirtFarmerJay you know I can't stay away.
You dont think just insulating the attic better would resolve this as well? I have way too many areas that gap in the winter
#SHOP
I want one of those hats you got
Carl - glad to hear you say that. You can head right over to dirtfarmerjay.com/shop and buy one from our store. Enjoy! Best, DFJ
Talk about my popcorn ceiling around fireplace is buckling and cracking. It was fixed once and repainted but looks bad now. A new bigger cricket was installed on roof to prevent water damage. I stuck a metal rod up between a crack and it hit hard sheet rock not pithy like water damage. So I’m thinking just bad patch job before letting go?!?
DrDennis77 - sorry to hear about this. I suspect you are correct. Is the sheetrock affixed to the ceiling well with screws or are their screw pops where the sheetrock has relaxed and is hanging loose on the screw heads? As you know, the problem with popcorn ceilings is getting a good match after the "real" work is done of getting everything done well structurally. Thanks for watching and taking time to write. Let me know what your solution is when you fix this. Best, DFJ
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Hi! I have a vaulted ceiling and found a crack today. Does this happen even in vaulted ceilings?
Yes it does. Uplift with the temp differential "tweaks" the shape of the room/ceiling, leading to those cracks that are more apparent some times of the year than others. Best, DFJ
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Your blocking technique while framing the way, you explained, it makes absolutely no sense