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We’re working with new construction in Pennsylvania. We recently installed 1/2″ drywall on our ceiling and a few hair-line cracks have developed on the seams between the trusses. The trusses are 30 feet long, 24″ o.c. The seams were taped with the self-adhesive mesh tape. The dry wall is glued and screwed. Are the cracks the result of the lumber drying (which will stop eventually), truss-lift (which will reoccur) or the tape (vs. paper tape)? Would 5/8″ drywall make a difference? And more importantly, what is the best fix?
Thanks for your help.
Randy Strausser
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Replies
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Hi Randy,
Did you install 1x3 at 12 inch centers across your trusses?
1/2" drywall over 24 inch spans with insulation will crack and bow.
Gabe
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Gabe,
Where would you install the 1x3's? On top of the bottom cords or between them? I am planning on blowing insulation into the attic space. Is there a recommendation for keeping the weight off of the drywall?
Thanks for your input!
Randy
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The 1x3 should have been installed under the bottom chord, between the drywall and the trusses.
This not only locks in or stiffens the trusses but gives you 12 inches between centers to screw the drywall to instead of the 24" span of your trusses.
If you didn't do this, even without the weight of the insulation, the drywall will bow down from it's own weight and humidity. Nail popping and tape tear will also dramatically increase from the movement in the trusses.
Gabe.
*Randy, it's the tape. Truss lift only occurs during the cold season. YOu are experiencing the problem suring the drying out process.Arond here, we always install board directly to the trusses on 24" oc without any problems of cracking. ONly paper tape is used however. Builders usually use batts and sometimes blow in additional fiberglass insulation over the batts.Still no problems.I've even seen wacky drywall crews install the 1/2" drywall parallell to the supports without any problem. That's unusual however.blue
*I'm with Gabe on this. My experience is that nothing will solve the problem except stiffening the structure the rock is fastened to. This kind of thing happens to walls too when they are subject to seasonal temperature variations and aren't stiff enough.Since it is new construction go back and add the fix. If this were a remodel I might not do anything depending on where the cracks are since there isn't any structural problem with this.
*different regions do it ... here in Rhode Island, most traditionally strap the ceilings (furr the ceiling).. we furr 16 inch OC for everything... it has a lot of benefits.. it takes out half of any variance in your ceiling .. and you can shim to zero variance if you want to , it gives a better surface for the board hangers to fasten to.. it provides a 3/4 inch space that you can block around for hanging specialty fixtures... it provides a channel the electricians can run some of their wiring in... and since we install a vapor barrier of 6 mil poly .. it helps to install the poly and keep it from being penetrated by the trades..it also relieves some of the thermal break of the trusses or rafters...... I do know that most of the country does NOT furr their ceilings.... but here , we can do it and stay competitive... because everyone does it..now that some of the national builders like Pulte are in the market , it will be interesting to see if they follow local tradtion... or vice versa.
*Randy,Did your framer nail the bottom chords of the trusses to any top wall plates? When the live loads (i.e. snow,wind, 8 tiny reindeer) from the roof plane transfers to the bottom chord and it is unable to flex something else will give first. If they have been nailed, pull the nails and install Simpson truss uplift clips instead to prevent side to side 'walking' as well as limiting uplift travel. Also check the truss manufacturers paperwork to ensure that the pre-engineered bracing has not been forgotten. I build in the Harrisburg area and when we use trusses the clips work.
*Since Randy describes his cracks as being "seams between the trusses", I doubt it has anything to do with truss uplift. And - as someone already pointed out - Truss uplift happens during the winter. So maybe a better description of the cracks would help. Are they parallel to the trusses, or perpendicular ?
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Thanks for all of your input. To answer a few of the questions that have been raised,here is some more info. Half of the main structure is balloon framed with 2x6 studs to create a great room (22'x30'). The other half is framed into two stories. We did install truss clips on the wall plates of the two story section. The cracks are "hair width" and run perpendicular to the trusses and there are traces of cracks in both the balloon framed and two story section.
As for the "eight tiny reindeer" prancing on the roof, my roofers recently revwoofersthe finishre visitedo de-install their roobe-installThese guys are "better-than-average" in physical stature. Their visit to the roof occurred between the time we did the drywall seams and when the cradry walleared.
I like the idea of the 1x3 straps- any tips on retrofitting?
Thanks a ton for your input.
Randy
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randy... were you using the spell chkr ?
it usally makes hash out of everyone's posts...hah !
*Don't count on Pulte to follow the local tradition. There won't be any furring material on site to use! Pulte is not afraid to build to the minimum boca requirements because they are often over built anyways. Pulte is very big on carrying their main bearing points. They have a long history of service and know where they need to concentrate their efforts. Furring ceilings is not going to be high on the list and the extra dollars will not be spent. Period!Blue
*I didn't think they would.. especially since they build for market and the homeowner will never even know if his ceilings are strapped or not... or care either..what i really wonder is if they can move the market to the point where soon nobody is strapping (furring) the ceilings
*Hi Randy,Roofers working on the roof should not have caused the drywall to crack. If this is the case, you may have problems in the winter if you have a heavy snowfall anytime.This is your home that we're discussing, not some track house being built for the unsuspecting masses.You can remove the ceiling and install the strapping as previously noted and re-sheet the ceiling but the edges of the ceiling would not fit over the edge of the wall sheets unless you cut them all back by the thickness of the strapping.You could block the ceiling by making a chalkline at every 4 ft. across the tops of your trusses. Then you screw in 2x4 blocks along the chalk line. One on one side of the line and the next on the other side. By staggering them, you get good contact with your screws to wood. Make sure that you cut the blocks to fit snug.You could screw straps over the top of the bottom chords of the trusses and install R12 FG between the chords of the trusses between the straps and the drywall. Then you lay another thicker layer of insulation over the top of the strapping.Regardless, only you can make the final decision as to what you want in your new home.I can assure you that any experienced builder can simply walk into a home and pick out the ones with 24" spacing. They will bow between the trusses and that's a fact. You don't need a straightedge either, simply look along the ceiling of any room with good sunlight and you will see the hollows.To save a few hundred bucks by aiming for the minimum acceptable standards for home construction is foolish. The day is near when builder liability will include 10 and 20 year warrantees on homes.Gabe
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Spell checker, huh? That's what caused the last paragraph in my entry to get screwed up. I didn't realize it until I printed it for my builder to read. Won't do that again. Thanks everyone for your input, this is a very valuable resource.
No one said anything about 1/2" vs. 5/8" drywall. Would 5/8" have helped in this sitution?
Thanks,
Randy
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I'm with Blue. It's the tape.
*since it is the tape joints that are cracking it wouldn't make any difference how thick the rock was. get the movement probmel fixed and your problem will go away.
*Gabe, I wonder why you need "good sunlight" to spot the "defective" ceilings. Is is because the tradespeople in your area don't know how to finish properly?YOu mention track homes as a means of bolstering your argument that stapping is needed. Well, do 10,000 sq ft ultra custom homes fall into "tract" type housing?I will say it again. No one has ever strapped a ceiling around here. They also don't use that inadequate open fiber self sticking tape because it allows the joint to telegraph through. Randy, if it's good enough for a millionaire, it should be good enough for you. Simply retape the hairline cracks with regular tape and remud properly. If the cracks reappear send me the bill.blue
*I'm still with blue... The only house around here I've ever seen with (some) strapped ceilings is mine! :^)Many houses I've worked on or built have roof trusses 24" O.C.
*Hi Blue,No, I don't need sunlight to spot a ceiling that has been boarded over 24 inch centers directly onto trusses, but someone who is inexperienced may have to.Regardless of the size of the house, you can build a 1200 square foot like a quality custom house or you can build a 10000 square foot house like a common track house. Cutting corners on a house is a sign of poor construction practices, not doing your client any favors.Don't you agree that any lenght of wood that is held in place so that it can't torque or twist will hold more load than one that is free to twist?Having said that, don't you also agree that the shear strength of a 1x3 nailed to a truss is greater than that of 1/2 inch drywall?BTW I don't use self sticking tape, only the standard paper tape.GabeWhile America asks the question, who wants to be a millionaire, I know one American who doesn't want to be a millionaire. (Bill Gates)
*Gabe:Novel slant on the "Who wants..." thing. Obviously the pitch is directed at the masses.Anyway, I don't think anyone disputes that the strapped ceilings are better. Only that they may not be necessary and that we must pretty much build with local custom rather than raising the price of the house upwards to a thousand $ for an item that most folks won't notice, even if we know it's superior construction. The new home construction business, like any other, is market driven.Still, this doesn't mean that houses without strapped ceilings are crap.PS: Here's another thought: Around here we insulate to R-30 in the ceiling, but I'm guessing that up there "north of the border" you probably go higher. I wonder if this has much bearing on the situation?
*As for the discussion of roof trusses 16" or 24" O.C. - I only see 3 or 4 houses a year that are 16" O.C. Are there places where 16" O.C. is common ?
*Hi Matt,No said that houses without strapping were crap. Yes there are regional differences in construction. Yes some place use more insulation and others use less or even none. But even if you didn't put any insulation at all, 1/2 drywall will sag more on 24 inch centers than if installed over strapping on 12 or 16 centers, with just the humidity.However, you hit it on the head when you said, never seen it other than "my" house. I'm extremely possessive when I build anything and I build as if it were mine. So, when I give advise, it's based on what I would do.Have a safe one,Gabe
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Blue,
Using 1/2 inch drywall on 24 centers is common practice around here. I consulted the local "elder drywaller" and he assured me that this is the technique that he has used successfully for lots of years. He also pointed to the mesh tape as the culprit. I cut a hole in the ceiling for attic access and removed a piece of drywall with a seam running down the middle. Looking at the cross section of the board and sean revealed the problem. Any gap in the seam is normally filled with joint compound before paper tape is applied. With the mesh tape that gap does not get filled. The result is that you only have a 1/16" thick layer of mud at the seam and the gap remains empty. Even the slightest movement in the drywall easily cracks the seam. We are going to repair it from above by filling the gaps with joint compound.
Thanks for all of your help.
Randy
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Randy,
Thank you. You just confirmed what I suspected was the problem in my own ceiling.
We bought an old farmhouse 14 years ago and went through it with a bunch of remodeling including new drywall. I was too busy to finish it myself so I let a drywaller do it. I got home one day and noticed he had used that mesh tape. The seams in the flats started appearing a few years later.
I had never thought a lot about it but when you mentioned the lack of mud between the sheets it made a lot of sense. I'm pretty sure that is the problem. I wish I had finished it myself.
Red dog
*Gabe, I'm not sure that you would be able to discern a ceiling that is fastened to trusses or straps. The finishers around here are pretty good at their craft. There's no stucco, or popcorn or any other surface other than smooth.All the drywall is glued. It does not sag. I repeat, it does not sag. I've worked enough remodeling to know that it does not sag.Strapping is just another layer of wasted lumber. The bottom chords of trusses don't wander around moving side to side. They don't twist and warp as studs do. The bottom chords are very stable except for the up and down movement of their uplift. Some trusses do not uplift. Others uplift a lot.I'm not sure about the 1x3 shear answer. Sometimes builders fight unseen forces that don't need to be fought. Is shear a problem with trusses. If so, why aren't the houses's in our area having shear problems? No house in the metro detroit area has straps and none are experiencing shear problems or ceiling sag. And none are experiencing cracking at the taped seams. The only differenc in the situation is the amateur fibertape. It's very obvious and very easy to fix. I find it ludicrous that some would suggest to him to remove his ceiling and strap, then rehang and tape. At least just try the different tape, then if the problem remains, go to theextreme and tear it all out. Give the guy a break! Don't tell him his house is tract trash and make him feel like strapping is the only way! It isn't and you can walk through any house around these parts for proof.Lets' start saving the owls. If your drywall sags 1/64" and you save a few owls, consider it your sacrifice for nature. Everything sags in nature. If you don't believe me, take a look in the mirror after you shower today!blue
*you will get many that will tell you that 5/8" is better. It probably is but probably not necessary. Fred is right, the poorly taped seams would have cracked anyways.I like your solution, I hope it works. I'd probaby make sure the mud filler is relatively loose. It will flow better. If that doesn't work you'll just have to re-tape down below.blue
*Hi Blue,Strapping is code here and its not because of any difference in the quality of tapers.Things started sagging a long time ago, what has kept it in check is preventive exercise.Keep safe,Gabe
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My drywaller uses that HD (high density) 1/2" drywall on ceilings. It is suppose to be more sag resistant than regular 1/2" and left over scraps can be used on walls.
Also I read where , one of the manufaturers of that mesh tape, had to put a disclaimer on the package, to the effect that the first coat must be setting compound, seems they were getting a lot of complaints regarding cracking.
As for strapping , around here in Iowa , the only time I've seen it used , is remodels , where some leveling is required.
*Randy, I would also blame the tape I have never had any luck with itmyself.I like the paper better it is more work but it is worth it.Also seeing that this is new construction you could place a 2x4 on the flat over the seems and between the truss bays attach it to the trusses then screw or nail to the 2x4.This should provide a backing for your sheetrock if it is saging.
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another way to rectify this is to backblock with offcuts of board.Cut them around a foot wide by whatever the truss layout width is. Glue in place making sure they are well bedded down. You can use either board glue or cornice cement ( cheaper and stronger in my opinion) to do this. It will be a time consuming process but worth the effort. Here we backblock this way as we are sheeting, ( only on the butt joints as we furr out all our ceilings ).
In times past we didn't used to furr. Having built both ways I can only say there can be no argument that furring isn't a better job.As I am required to cover my work for 6 years from hand over, I wouldn't have it any other way.
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If the drywall joints are too tight and self stick mesh tape is used then the mud can't squeeze into the joint and the cracks appear. Even if there is a penny width space between the sheets of drywall the tapers might succomb to the temptation to just skim the surface of the mesh tape when working at that height.
Paper tape doesn't crack because the compound is automatically forced into the joint when the tape is set into the mud.
With mesh tape you must have a slight space between the sheets of drywall and you must force the mud into it.
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We're working with new construction in Pennsylvania. We recently installed 1/2" drywall on our ceiling and a few hair-line cracks have developed on the seams between the trusses. The trusses are 30 feet long, 24" o.c. The seams were taped with the self-adhesive mesh tape. The dry wall is glued and screwed. Are the cracks the result of the lumber drying (which will stop eventually), truss-lift (which will reoccur) or the tape (vs. paper tape)? Would 5/8" drywall make a difference? And more importantly, what is the best fix?
Thanks for your help.
Randy Strausser