Old method of bonding
plaster to old walls

Ask the pros- September, 2002
By Reggie Bullard



      Hello,We have a 1930 tudor house in California, all old plaster inside. Some  rooms had wallpaper, some were painted over plaster. My question is: is there a method to adhere new plaster without having to use any plaster-weld or other modern products containing formaldehyde and other not so environmental ingredients? Any old world knowledge? How was it done about 100 years ago?

Plaster was bonded to plaster 100 years ago by 
chipping the wall with a hatchet or chisel. 
These chips were made generally about 6" 
on center. Then, the old wall was coated 
with heavy gauged lime and gauging plaster 
(that is a high percentage of plaster to lime), 
and no retarder(which weakens the mortar. 
I have seen this a lot in old 1800's buildings. 
It wasn't as reliable as plaster weld, and usually 
the new finish coat can be scraped off. 
Even though this method worked, it couldn't 
withstand much abuse.