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-   -   hairline cracks in plaster (http://www.diychatroom.com/f4/hairline-cracks-plaster-125626/)

Npcuzzupe 12-04-2011 09:43 PM

hairline cracks in plaster
 
Hi everyone,
My wife and i just bought our first house and there are hairline cracks in the plaster EVERYWHERE. They are under every window, throughout a few of ceilings and under a couple of beams. The house is from the 1950's, and a contractor told me that this is normal, and was probably just never fixed when it initially happened. Can i just mesh tape over these and compound them or should i cut them out a bit to prevent them from happening again, THEN mesh tape and compound?
THanks,

Snav 12-04-2011 09:51 PM

Just smush new compound into them.

He's right: if it's everywhere it likely happened in the beginning. Their plaster/mud 'shrank' as it dried - pulling apart from itself. whenever plaster beds or textures are used you're suppose to touch things up before you paint.

Npcuzzupe 12-04-2011 10:01 PM

Should I scrape them out a bit so that the compound can bond or use durabond rather than light weight joint compound ?

Snav 12-04-2011 10:12 PM

Yeah - that's a good idea.

Brushjockey 12-04-2011 11:16 PM

Don't mush anything- lol
Larger cracks are caused by the plaster moving from the lathe- I use screws to refix it to the lathe- take s special touch to not over spin and get just below surface.
No tape will mean they will come right back - unless very hairline. So use tape on anything major.
Usually by the time you've feathered them out you are resurfacing the whole wall- i do it this way often.
Screw- tape, set tape with hot mud- fan out 2nd coat hot mud-skim with premixed, sand, prime, look over & touch up mud, respot prime, finish.

Gary in WA 12-05-2011 12:18 AM

I agree with previous, Bj. I use paper tape with 20 min. compound, not all-purpose- air dry. The paper hides the expansion/settling cracks better than mesh tape in the future; http://www.usg.com/rc/technical-arti...e-en-J1190.pdf
http://www.usg.com/rc/data-submittal...ata-MH1178.pdf
When installed originally, it was smooth. Cracks happen from movement. Use a can opener point to under-cut the crack and water mist the sides (some use a bonding agent). To refasten chunks, use special plaster screws- Google it.
http://www.nps.gov/history/hps/tps/briefs/brief21.htm

Gary


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