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Drywall help/advice needed


superdave1984

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So we closed in our carport and made a bedroom. Hired a reputable guy who we had used for other stuff in the past.

The carport had vinyl siding on the walls, he took that off and underneath was tongue and groove pine siding. Under that is tar paper then 1x6 planks then studs. This was on 3 walls. Drywall went over top of t&g. The ceiling has plywood on it and he went over top of that with drywall. He used 3/8 for walls and 1/4 on ceiling. Built one new wall where carport opening was.

Job looked fine until we put primer on the drywall, and then we saw cracks in the joints. Nearly every one of them. Called, he comes back and spreads some lightweight filler, sands, says it should be fine. Said he called a guy who does this stuff every day and he said that it's probably a moisture problem and to use this particular stuff and it will be fine. Wrong. Next day cracks were back. We call an insurance guy we know who brings a moisture meter to test. Dry as can be. Called a local builder who asked a few questions and said it's the mesh drywall tape. Said it's crap and should only be used for repair work.

Called the guy, he comes back and cuts out every joint in the room, removes the mesh tape and goes with paper. That was finished Monday. Cracks are back. WTF!!??

I need a drywall guru to tell me what the hell to do now. Do I need to rip down all of it and start over using thicker drywall? Do I need to remove the plywood and t&g? Weird part is the new wall cracked too, not just the existing construction that he went over with drywall. This house was built in 68 so I doubt there is any settling left to do. House is SOLID built.
 


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straycat

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This is strange. I have done several projects years back and never saw anything like that. I tell you what I really would do, Dave. I would just spray all the drywall (ceiling as well) with a light weight Spackle and this will give it a good cover. You can add some texture to it if you want to on the walls or even the ceilings. Some people like a really smooth finish and some people like the textured look like I do. This spay on technique will cover any impurities.

Hope this helps out, Bro.
 

fyre82

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Primer, texture and paint should cover that cracking. Its probably the mud cover that dried to fast or something. I'm not a drywall guy, but that's what my intuition says . . .

Seems a shame to cover T&G unless it was garbage to begin with. But I like wood finished walls.

Rich
 

88B2EB

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Was the backside of drywall glued before it was scewed in? Reason I ask is 3/8" and 1/4" are REALLY thin. Typical for residential is 1/2" walls and 5/8" ceilings. Ceilings are thicker to prevent sagging. If 1/4" was used and not glued it might be sagging and causing cracking at the joints. I can see using 3/8" on the walls if there's already a T&G substrate but that's usually a pretty uneven surface and if the drywall wasn't glued down it could be settling against the wall causing cracks. Without seeing it it's hard to say but that's my guess. Putting a drywall texture on the walls might help a bit but ultimately it's the joint tape that prevents cracking. The builder you talked to probably knows more about joints than me, I did drywall for just a few years and am now an Architect, but I always used mesh tape for repairs because it's STRONGER and used paper on new walls because the more expensive mesh tape wasn't necessary. If you've primed and the cracks are still showing you might try wallpaper or if you don't like that look maybe a good commercial wall covering. Hope you get it figured out.
 

cvar

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Sounds like the carport itself is shifting with the winds, etc. If that's the case, no amount of gap filler will avoid cracks. The drywall is only a skin (chalk & paper), and the walls must be rigid enough to prevent flexing. Otherwise it will always crack. No matter how thick your drywall, and no matter how well it was applied.

I think you may need some diagonal cross-bracing inside your stud walls. I suspect that was omitted for a carport.

Do you mean T&G siding or T&G shiplap? Shiplap is smooth, and would make a good smooth surface for drywall. Wavy siding would not.

One more thing. Building code says garages must use 5/8" thick "firecode" drywall, not regular stuff. Firecode has fiberglass threads embedded, and burns more slowly, giving you 1 hr to escape a burning house. The 3/8" and 1/4" stuff is way too thin. Why skimp out when 5/8 firecode is safer, quieter, and only costs $2 more for 4x8 sheet?

Lastly, there are 2 kinds of drywall joint (mud) compound: "regular" and "setting". Both are mixed with water. The regular kind cures by water evaporation, and shrinks & cracks as it slowly dries overnight, and is soft & easily sanded & easily cracks afterward. The "setting" kind is way better. The "setting" kind cures by chemistry (much like 2-part epoxy), so it cures in 20, 45, or 90 minutes (see label) to rock hard, not by evaporation, and it's much harder to sand, never cracks during curing, and also harder to crack afterwards.

For least cracking, paper-tape the joints and use "setting" type mud. But that's still pointless if the wood is shifting underneath.

Did you upgrade the electrical wiring & outlets before covering the walls?
 

88_Eddie

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i'd get a thicker drywall for the ceiling. it sounds like the 1/4" is flexing somehow and causing the joints to crack. even if you spray the textured stuff up there, there's a chance it flex and start falling out as well.
 

superdave1984

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Sounds like the carport itself is shifting with the winds, etc. If that's the case, no amount of gap filler will avoid cracks. The drywall is only a skin (chalk & paper), and the walls must be rigid enough to prevent flexing. Otherwise it will always crack. No matter how thick your drywall, and no matter how well it was applied.

I think you may need some diagonal cross-bracing inside your stud walls. I suspect that was omitted for a carport.

Do you mean T&G siding or T&G shiplap? Shiplap is smooth, and would make a good smooth surface for drywall. Wavy siding would not.

One more thing. Building code says garages must use 5/8" thick "firecode" drywall, not regular stuff. Firecode has fiberglass threads embedded, and burns more slowly, giving you 1 hr to escape a burning house. The 3/8" and 1/4" stuff is way too thin. Why skimp out when 5/8 firecode is safer, quieter, and only costs $2 more for 4x8 sheet?

Lastly, there are 2 kinds of drywall joint (mud) compound: "regular" and "setting". Both are mixed with water. The regular kind cures by water evaporation, and shrinks & cracks as it slowly dries overnight, and is soft & easily sanded & easily cracks afterward. The "setting" kind is way better. The "setting" kind cures by chemistry (much like 2-part epoxy), so it cures in 20, 45, or 90 minutes (see label) to rock hard, not by evaporation, and it's much harder to sand, never cracks during curing, and also harder to crack afterwards.

For least cracking, paper-tape the joints and use "setting" type mud. But that's still pointless if the wood is shifting underneath.

Did you upgrade the electrical wiring & outlets before covering the walls?
The t&g looks kind of like this, but is individual boards. And not as pretty.

3/4" thick, about 8" wide, smooth finish other than where the boards meet. They are run vertical not horizontal. Behind that is 1x 6 or something run on a 45 degree angle. That's how three of the 4 walls are. I would've bet my life that would be a very stable wall and wouldn't move at all.
I doubt there's any shifting due to wind, the house has marble on the exterior. The carport was built under the original roof, not an add on. The only exterior wall without marble is the new wall which has vinyl siding.

I wondered about using the thinner sheetrock, but figured he knew what he was doing. I'm sure he had a reason but I don't know what it was.

We had new wiring and outlets put in during the process. Wish I had some pictures...
 

88_Eddie

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I wondered about using the thinner sheetrock, but figured he knew what he was doing. I'm sure he had a reason but I don't know what it was.
it's lighter, if he was working alone or with only one other person, it's much easier to put on the ceiling.

i've only used 1/4" sheetrock on one occasion. i used it on a wall that had so many chip marks and divets and pin holes in it, that it would've taken weeks to mud and sand. i used drywall screws and liquid nails to fasten it to the wall, mudded the joints and was done in a day. i wouldnt have used 1/4" on a ceiling unless i was covering up drywall that was already there.
 

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if you think about it a 4x8 sheet of 3/8 is about 45lbs so if you have a 12x16 carport that's 14 sheets on the walls and 6 on the ceiling that is probably close to at least 1000lbs + on 6 to 8 poles so it probably just settling cousing the cracks
 

cvar

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Using 3/8" thick DW can work fine, it's just chinsing out a bit. 1/4" is asking for it. That smooth shiplap can be a great substrate.

Discussing all the possibilities (from way over here)...

Am I correct to assume the cracks aren't simply from shrinkage due to piling on overly thick pre-mix joint mud? That would be incompetence. One overly thick (1/4") layer of regular evaporating mud would be stupid. Instead, I'll assume 3 thinner layers of "setting" type mud, incl. tape, and each NOT applied until each prev layer has set.

Once cured, DW joints don't crack for YEARS unless flexed, even if it's just 3/8" thick. Flex also includes in/out, not just up/down. So what's loose?
Why is it cracking so FAST?

If the framework of walls are rock solid, then excellent cuz they won't make your DW sheets flex. So what did cause it to flex & crack? Either the substrate itself is a bit loose or else the DW wasn't well fixed to the substrate. Nothing else would explain it. Liquid-Nails & long screws helps the latter. Was T&G firmly screwed down to the studs before hanging DW? On both sides of every joint at least. Yes, you can still screw down the T&G to its studs right thru the hung DW, but good luck finding studs & avoiding wires/pipes. You can always skim coat over lotsa screw holes.

Me? I'd strip DW, re-screw T&G to studs, and hang normal 1/2" or firecode (ie, 5/8"), even on ceiling. DW & mud is cheap. Paying for labor is not. Funny how universal that is.
 

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Was the T&G screwed down before the drywall went on? The substrate could be unstable if not anchored correctly.
Thin drywall shoulg be used for radius walls or overlays and attached with liquid nails or drywall mud.
1/4" and 3/8" thick drywall there is no room for the nails to suckup and be lower than the surface to allow for the mud to cover.
There is now light weight drywall available at all Home Depot, it is +/- 10lbs lighter per sheet at 1/2" 4'x8", works great.

Good luck.
 

lil_Blue_Ford

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I've never played around with thin drywall like that so I can't speak for if that is causing a problem itself or not. I've seen where "professional" drywall guys tried to hurry up and skimped on doing the taping right and had it crack or bubble. Had it happen with the house I'm in. Called the guy back, he patched a couple joints and said that it's fine. They all bubbled/cracked again and he stopped responding to calls. Said he didn't know why it was happening and blamed that the walls must be moving. Right. I'm sure the 5" thick concrete wall is flexing when the wind blows.....

I suspect the problem was how they taped the joints, using just enough mud to stick the paper tape to the wall. When I was taught to do drywall, I was taught to lay a thick bed of mud in the tape groove, then stick the tape to it, then use a 4 or 6" knife to firmly seat the tape in place and squeeze out all of the excess mud. I've used the premixed type of mud that cures by drying out, and usually use the lightweight stuff. So far that method has worked out well for me. Did two rooms at the house here (in the basement where the so-called professional didn't do because it wasn't ready) and did a couple jobs for other people and it's always worked out well. I set the tape then go home for the day. When it's good and dry I start work on the build-up.
 

Mark_88

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I have taped a few thousand feet of drywall and used several different products over the years that have never cracked. I've done similar to lil_blue where by laying a thin layer then sticking the tape to it and slowly building it up...but I've also used the mesh tape quite a bit lately...

The mesh tape is easier to apply because it is self adhesive but found you really need to work it more to get it smoothed out and not showing the grid pattern with too much sanding...

While reading this I was curious about the actual construction.

It is common practice in Canada to not apply drywall directly to any surface on an outside wall. All outside walls should be insulated (regardless of climate since insulation can help keep rooms cool or warm) and then covered with vapor barrier.

Did you use vapor barrier on the outside walls and, if not, are these the areas where the joints are cracking?
 

superdave1984

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The t&g is nailed using 3" nails in the grooves. It was a beeeeyotch to remove the one wall he took off. there's tar paper on every wall as a moisture barrier.
 

Mark_88

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Hmmmm...OK...so where is it actually cracking? All joints, or just on certain walls?

I've used the glop in the big bucket mostly...leave it to cure for 24 hours before any prep or adding more to it...drywall compound is the generic name...but probably sold in a dozen or two flavours...
 


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