old expanded metal lath for plaster?
I ASSumed that my house had gypsum lath, but after (finally) fixing the
ceiling in my kitchen I now realize that most of the house is metal lath
and the gypsum that I saw previously was a spot repair.
The reason that I ask is, in several rooms I have cracks in the ceiling
running the length of the room, quite evenly spaced, and perpendicular
to the direction of the joists above. My suspicion is that it is the
"joints" between sections of metal lath. I also am inclined to "fix"
said cracks by shooting drywall screws into the joists on either side of
said cracks, then using mesh tape and drywall mud to conceal. Sound
reasonable? Should I use washers to help support screws? If so, how to
countersink? Buy a Forstner bit and treat it as disposable?
replace "roosters" with "cox" to reply.
What is the spacing of the "cracks"?
I a bit surprised that the cracks formed. The expanded metal lath
should have be overlapped, which should have created a "lap
splice" (a kin to rebar in concrete) that shouldn't have allowed the
plaster to crack.
I'm not sure that the screws, the drywall compound & tape fix is worth
I would try a flexible caulk, worked well into the crack, as an easy
but possibly lasting fix.
Adding screws to a metal lath plaster ceiling will do little if
anything...The joints in the metal lath are over lapped at least 4 inches
and secured with SS staples and tied with wire if it was done properly and
I'm assuming it was....Repairing it with joint compound will only hide it
for a while....BTDT....It most likely will come back...Caulking and paint is
how I'ld go or just not worry about it...Most new metal lath plaster
ceilings now have expansion joints on big ceilings more than 120 square feet
, IIRC.....Same for cement slabs as well ..They WILL crack if there arent
any...Plaster over metal lath is just a 1 inch cement slab on the
ceiling...My new slab under my garage has expansion joints.....Plaster
(blue) board is a whole different animal and doesn't crack..The plaster
board is stronger than the brown coat over metal lath which is why you don't
see metal lath much anymore except for historical renovations , commercial
jobs and curved surfaces that plaster board won't go around without
breaking..Metal lath is also more time intensive therefore more
I just measured the cracks in the living room, they're almost exactly
16" apart. Did not measure in the upstairs bedroom, but those look similar.
I didn't post the measurement before because a) I hadn't actually stood
on a chair and measured them and b) wanted to see if my theory would
Now I'm more puzzled than ever. I will try to snap a pic of the bedroom
ceiling (cracks are more pronounced there) to see if it says anything to
anyone. Odd thing is that these are two different rooms, on two
different levels, on two different sides of the house, with the joists
running opposite directions, and the cracking looks very similar in both
rooms. There's some faults here and there elsewhere throughout the
house, but nothing like this. The living room is not horrible, but we'd
like to repaint, and I don't like doing hack jobs. The bedroom is
Someone using up some lath scraps back in the day?
replace "roosters" with "cox" to reply.
board is stronger than the brown coat over metal lath <<,<
Please explain why you believe why that plaster board is stronger than
plaster over metal lath.
I just don't see how that can possibly be true.
A floated shower enclosure with lapped and wrapped expanded metal lath
has got to be way stronger than a green board, blue board or wonder
board enclosure (w/o any metal lath).
Metal lath is usually 27" wide, meant to lap and give about 24"
coverage. If your cracks are near 27, someone did not install the
lath correctly or did not tie the laps. Ribbed lath has been
installed wrong and will cause a stress crack system of lines -
the ribs should be against the framing to allow proper plaster
keying into the lath.
Keep the whole world singing . . . .
Ever tried to drive screws through a metal lath and plaster ceiling AFTER
finding the joists ??? NOT FUN....BTDT got the T-Shirt....If going with the
sheetrock over it idea , and I wouldn't because it sounds as if the ceiling
already has structural issues and adding weight could make matters
worse...Plaster over metal lath is much heavyer than drywall or blue board
with plaster... The ONLY way I would do it is shoot on some strapping with
a nail gun into the joists and sheetrock over the strapping...MUCH
easier....If the ceilings are *really that bad* there is only one thing to
do and I know you don't want to hear it...Good luck....
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