Several points need making here:
1. Most drywallers and DIY'ers both really don't know what the purpose
of the joint tape is. It's there to carry any tension across the joint
without the joint breaking.
You see, drywall is actually fairly rigid considering what it's made of,
and that's entirely because paper is very strong in tension. Try
folding up a piece of paper and pulling on it hard enough that it
stretches until it breaks, and you'll see what I mean. So, for drywall
to bend, then the paper on either the front or back has to stretch, and
since it takes a lot of force to stretch paper, drywall is really quite
(This is exactly the difference between ordinary concrete and
"reinforced" concrete. A reinforced concrete slab will have steel
rebars embedded in the concrete near both it's upper surface and it's
lower surface. The idea here is that for the concrete slab to bend, the
steel rebars on either the top or bottom have to stretch. Steel is very
strong in tension, and it's those steel rebars that make "reinforced"
concrete slabs so much stronger than concrete poured without any rebar,
or with only a single layer of rebar in the middle of the slab's
thickness (where the steel rebars will do nothing to help prevent the
slab from bending.))
The problem is at the joints. If a wall bends outwards (so that the
face paper of the drywall stretches) then unlike the face paper of
drywall, the joint compound over the joints will crack before it
stretches as far as it needs to, and so the purpose of ANY drywall tape
is to carry the tension over that drywall joint so that no cracking or
Now, paper drywall joint tape isn't nearly as strong as the face paper
on drywall because it isn't nearly as thick. Fiberglass joint tape is
stronger than paper tape, but being that it's at the bottom of the
contour, it's not in the best location to carry the tension across the
joint. Ideally, you'd want to glue the same kind of face paper they use
on drywall over the joints so that the paper is equally strong
everywhere, but that's neither practical nor attractive. But, that's
what would give you the strongest drywall installation.
Using drywall tape on inside corners doesn't make any sense at all from
an engineering perspective. Paper in that location won't do anything to
prevent the joint compound from cracking if the joint flexes or moves,
and the paper won't do anything to prevent that joint from flexing.
2. Don't let butt joints be a pain in your butt.
Most home centers now sell "curved trowels". At first glance, a curved
trowel looks identical to an ordinary plastering trowel. It's not until
you set it down on a flat surface or sight along it's edge that you
notice that the blade on it is curved. Specifically, it arches upward
in the middle by about 1/8 of an inch:
Since you hold the trowel at a comfortable angle to the wall when
spreading joint compound, a curved trowel allows a total newbie to
spread a perfectly symmetrical mound of joint compound over a butt joint
that's no thicker than about 5/64ths of an inch thick in the middle.
This is plenty thick enough to bury fiberglass mesh drywall tape in, but
not thick enough to create a noticable "bump" on the wall over the
joints, not even with wall mounted light fixtures. Years ago, it was
rare to see curved trowels in home centers; you pretty well had to go to
a drywall & plaster wholesaler to buy curved trowels, but now most
hardware stores will carry them. They make finishing butt joints (where
you don't have a contoured edge on both sides of the joint) an absolute
When my sister's basement got flooded, I helped her replace the water
damaged drywall. We replaced the ruined drywall with Georgia Pacific
Dens-Shield for water resistance, and my sister used my curved trowel to
do all the butt joints where the Dens-Shield met the ordinary drywall.
That was my sister's first time doing any kind of plastering work, and
she has wall mounted light fixtures in her basement, and the job turned
out perfect. You can't see any "bump" in the wall between the
Dens-Shield below and the drywall above.