Butt Joint Problems

AARC Drywall

Hey all..
One of my guys is having a problem with his butt joints....very odd in fact.
even after coating several times, he can still see the tapes, and or can see that there is a hump in the wall where the but joint is.

I suspect that he is over coating the center of the butt joint, and not furing out far enough, but thats just me.

I suggested to him that he should try the following.

1. put tapes on and coat the center soon after.
2. coat again with 7" box next day.
3. coat with 10" box when dry
4. coat with 12" box when dry
5. touch up by hand if needed.

and do not sand the center if you can help it.


Its getting cold up here now, so i am wondering if that is playing a factor.
He might be coating without heat and letting air dry....????


any suggestions guys.
J

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taper71

My butt joints are 24" wide on first coat after tape and about 30" on skim coat. The tape itself should only have just enough mud to cover the tape.

I would think that if you are just using your boxes to cover the tape then that is what your problem is, as the box would just crown over the tape . Even if you feather out the sides you will still have that crown in the middle.
I use the boxes on each side of the tape first and then coat the middle ,after the mud has set up for awhile, and feather it into the flat aswell with a 12" knife. I have no issues with my butt joints.

Now all you butt taper and back blocking fans chime in and tell us how my butt joints suck

ajpepe72

Here in the uk we only use paper tape for internals, all tapered and butt joints are meshed with scrim tape, I'd say try scrim on the butts, its a lot thinner than paper tape and coats up fine with just the normal 3 coats, but make sure you use a setting compound for your first and preferably second coat, such as lafarges fast set.
If we are in a apartment that we can do in a day, we will use fast set for first and second coats and an air drying finish compound for the final coat.
If its a larger property and we know we wont be putting the finish coat on until the next day then we use fast set for first coat, then 10" box with air drying compound, then 12" box with air drying the next day.

mud dog

What I don't understand is why you can see the tape and the walls are humped? Is the board solid behind the tape, is there quite a difference in the height of each board? Put your trowel against the wall and see which side needs to be loaded up. I tape, then let it dry first. Then I coat in a similar way as Taper 71. By hand you could take a trowel full up the middle, one on either side. Feather each side and make one more pass up the middle, let dry, sand lift offs and repeat. Done and to quote Shell Busey "It's just that easy"

Zendik

Try cutting a small bevel on the surface of each sheet where they meet, getting rid of any soft paper.

BattleRidge

yes v'ing your butts should be quite standard you would think

Kiwiman

Make sure when you tape the butt that it is 100% bone dry before giving it another coat, otherwise it will just keep swelling out with every coat and lock in moisture. You say it's getting colder so it could well be your problem.

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PA woodbutcher

Basically the same thing here except no bazooka. Tape and set with a 6" knife and let completely dry. Run both sides with a 12" knife let it dry and then come back across the middle with the 12" again. Unless there is a problem with the board underneath, crowned stud or joist I generally have no problems.

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AARC Drywall

Thanks guys i wil give it a try myself tomorrow...

__________________
Profit is NOT a dirty word....Cheap is....

Preacher17

OK first get rid of the box and knifes.... Hawk and troule I will gurantee no tape......

If your going to use box...

use the 10" down bothsides of the tape, run the one wheel right down the middle of the tape.

When dryed run a 12 down the center of the tape.

then 10 should be set to 4 or 5 for more mud and the tweleve on 3....

but for the best job use a troule.... If you still have problems AARC let me know I will come up there and fix it for ya.......

The cold has put us behind by 3 days now on my last house.... NO HEAT... dam contractor......

d's

I'd agree with the hawk and trowel method and that its better to go down the sides of the tape rather than over top. that way you're starting off with a wider and mellower crown.

I prefill my joints with con fill or setting compound to avoid any weirdness down the track, tape(with taping compound), let dry, then apply a first coat of setting compound on both sides of the tape with a curved 10" drywall trowel(20" wide). For the second coat I use a flat 10" finishing trowel up the middle and then down both sides(30" wide). Finally polish with 12" knife and sand out. Not much mud over the tape but a very flat joint. Very rarely some tape will show through and I hit them when doing final touch ups.

Using setting compounds for all first coating helps to keep things moving as the temperature drop through fall. I would think that the amount of moisture needing to be exhausted is reduced as well due to it being bound chemically with the setting compounds - ie less window condensation.