wrote in message
...
On Sun, 06 Jan 2013 17:08:03 +0000, Tim Watts
wrote:

On Sunday 06 January 2013 14:42 Frank wrote in alt.home.repair:

On 1/6/2013 9:37 AM, Robert Macy wrote:
how to repaire [and prevent future cracking] WITHOUT adding a big LUMP
to the seam?

The wall run is around 60 feet and 10 feet tall. the junction right in
the middle is wanting to crack. Trying to keep from forming lumps on
the wall, I cut down, used paper tape with a layer of mud under and a
layer on top. [Many may remember the problems I had posted earlier. I
tried to wet the tape first thinking of wall paper and how that
shrinks to fit, but wetting CAUSED the paper to 'slide' as it dried
and thus a crack, so in response I took all that out and did it again
with dry paper tape, which did work better. Only had the tiniest of
hairline crack form all summer long only about four feet of run on the
wall only.]

Well this winter as we isolated that section of the house - meaning
cooler temperatures and probably contracting drywall sheets, the
crack(s) opened up with a vengence! I mean over 3 mil separation!, but
worse the crack is the full floor to ceiling AND even now goes up
along a ceiling section which I never had trouble with before. I
suspect in the heat of the summer the crack will close back up, too.

Yes, I know houses change shape with time, but this seems too much to
be caused by 'settling'. My conjecture is is that this is more caused
by 'flexing'. Oh yeah, the seams are ON a stud(s), so there should be
no reason for movement there.

So, my question is
How do you repair/prevent cracking at drywall seams WITHOUT creating a
huge lump on the surface? I already have built up 1/8 inch thick to ++
on these stupid seams.


I've used fiber glass tape, looks like screen, on cracks around door
frames that kept coming back. OK today.

+1

This is the only "proper" way to do drywall joints. The tape spreads the
strain over enough area that the plaster/filler on top can tolerate it
without cracking.

Here in north america paper tape is the norm - the drywall is paper
faced with a tapered edge - the joint is mudded, the paper tape
embedded, and the surface leveled with mud.

Perhaps using a "curing" compound instead of a "drying" compound would
make a difference??.(Also called "Hot mud" or "quick set" or "setting
type") - has a number as part of the name - like "sheetrock 45" or
"durabond 90" It is higher strength.. The normal stuff is awfull to
sand - but there are now easy-sand versions. I would not use the
setting type for fine finishing.

The only time I've seen paper tape in use was to joint drywall that was
painted direct without even as much as filling the joints - eg a crap
bodge
(cheap 1980's apartment builders in south London). Noone who is sane
and/or
not cheap would do it like that now.


I agree about the mud. Everyone appears to dwell on the tape. Durabond for
the first coat should solve the problem.