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w_tom
 
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Default repairing crack in drywall ceiling ?

Never use mesh type fabric tape. It only makes future
cracks easier. The purpose of tape is to make spackel
flexible. Much like steel rebar makes concrete flexible - so
that concrete will not crack as concrete moves.

Mesh tape provides no such flexibility function. Only paper
tape provides flexibility to keep tape joint from cracking
again.

Properly noted is to put sheet rock screws in before
taping. Cracks could exist because two sheets are not joined
together by a common piece of wood. Every adjoining sheet
rock must share and be attached to a common piece of wood -
even in inside corners. Otherwise cracks can happen.

Then since both sheets and wood may still move, then we use
paper tape - not mesh tape - to give the spackel some
flexibility without cracking.

Make sure that the entire interface between paper tape and
wall is 'glued' together by spackel. If just one air spot
exists between tape and wall, then either tape will peal off
later or spackel will crack. The reason for mesh tape is that
some tapers fail to properly seal every cubic microinch of
tape to the wall using spackel as the glue. Paper tape always
makes a stronger surface.

How to get tape to properly stick means putting about 3 or
more times spackel on the wall, then applying tape. Use
spackel knife, angled, to pull spackel up length of tape while
spackel also squeezes out the side. This 'spreading
lengthwise and sideways' simultaneously, will eliminate all
air pockets. Any one air pocket causes pealing and spackel
cracks. Tape is pressed fully into wall - minimum amount of
spackel between tape and wall makes a better glued surface.

Chet Hayes wrote:
A drywall seam is where one sheet joins another. At that point, tape
is used.

Before repairing it, to be on the safe side, I'd put some additional
drywall screws in the ceiling in the areas bordering the crack.

Then, I'd use the mesh fabric type of tape and joint compound to fix
the crack. With 3 coats and a wide knife, you can taper it so it will
be unnoticeable.