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Plaster repair

n8affleck's picture

I have a large section of wall that was recently framed in that butts up to an existing wall that has the original plaster (rock lath + plaster + final coat).  The rock lath appears to be about 1/2 or maybe 3/8?  and the plaster is another 1/2 inch or so making the total wall thickness about an inch.  I'm trying to figure out the best way to match up the existing sound plaster...

My plan is to cutback the plaster to the center of studs and place 1/2 blueboard (or equivalent???) and apply a brown coat and a finish coat totally about 1/2+ of plaster.  Does this sound like a solid plan or an overkill?  Can someone recommened a better way to match up the existing plaster which seems to vary between 7/8 and 1 1/8 I'm open to suggestions?  Maybe I should use 5/8 blueboard, or equivalent? I'm also looking specifically for help in the selection of the plaster mixes to use for the brown coat and the final coat.  Specific product choices would be helpful.  

For an entirely new room add-on, I'm thinking the blueboard + veener plaster looks like a nice in between option instead of having to plaster the entire new room, but still keep the old charm of the plaster.  What product is used for the plaster, and what is the maximum thickness of this material can be used?  I understand it's normal to apply about 1/8 of an inch or so.

Structolite is the material (post #204541, reply #1 of 2)

Structolite is the material for the brown coat. You can get it at HD. in this area[mich]. The plaster mix comes from a drywall wholesaler. You can get strucolite there also.If you want the solid feel of plaster use 1/2 in blueboard then bring to thickness with structo. Skim coat is used to smooth the structo as it is a gritty material. Make sure you use Plaster Weld at the transition to old plaster. This stops wicking and helps adhesion. Also at wholesaler. 

Drywall+PlasterWeld+StructoLite+Imperial Plaster Veneerthe (post #204541, reply #2 of 2)

Thanks Klepco--this is almost exactly my approach. A couple days ago I picked up the structolite product, and imperial veneer plaster.  I broke back the existing plaster with claw of hammer a few inches to expose existing good rock lath and provide existing brown coat to adhere to new brown coat.  I butted up the1/2" drywall to the 3/8" rock lath over studs.  I taped seams with fiberglass tape, and I'm hoping the difference in height will not be prone to cracking after applying the brown coat and finish? Will be applying brown coat this weekend.

I couldn't find any type of plasterboard in my area so picked up regular drywall and coated entire surface and surrounding existing plaster with plasterweld.  This was the best alternative I could find to blueboard.

Looks like so far I'm not totally off.  All other advice has been to just install and shim drywall, tape edges and use joint compound to taper into existing plaster.  I can't imagine how this would look good next to a 80 year old plaster wall with varying degrees of thickness over a 6 x 7 foot section.  I hope this is the right approach and not an overkill.

For entirely new room I believe I'll be using the 1/2 drywall,fiber glass tape in seams (Joint compound or just veneer finish in joints???) , coat with plasterweld, and a skim coat of the veneer plaster an 1/8".  Should help maintain the pre war feel of the home.

Thanks again for your feedback.