how wide was...

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?

nate

Reply to
Nate Nagel
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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 the effort.

I would try a flexible caulk, worked well into the crack, as an easy but possibly lasting fix.

cheers Bob

Reply to
DD_BobK

I think what you describe is a 3/8" *mesh* metal lath (sheet would be

3x8 feet?). Can you post a pic of the "cracks"?

Old wood lath looked like this from behind.

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Reply to
Oren

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 costly.....HTH...

Reply to
benick

Weight per Square Yard Type Finish Sheet Size Pcs per Bundle Sq. Yards per Bundle 1.75 lbs. Galvanized 27" x 96" 10 20 2.5 lbs. Galvanized 27" x 96" 10 20 3.4 lbs. Galvanized 27" x 96" 10 20 50 bundles per pallet equals 1,000 square yards

Reply to
benick

k..The plaster board is stronger than the brown coat over metal lath

Reply to
DD_BobK

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.

Reply to
DanG

Nate... I would add 3/8 dry wall sheets. Tape and finish. Seems like that would solve problem. WW

Reply to
WW

Hmm.

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 hold up.

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 borderline unacceptable.

Someone using up some lath scraps back in the day?

nate

Reply to
Nate Nagel

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....

Reply to
benick

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