Helpful? 0

Lime plaster over existing plaster and block

Hi, I am working on a fire restoration. The home is concrete block on the exterior walls that were previously finished with plaster. It looks like the block had been coated with an adhesive, and I have had had to grind down to the scratch coat to remove the heat and soot damage. The "key" has been broken in many spots-which are now down to the block. There is some remaining wire, but only around window and door frames. I have ordered NHL and want to mix it with different grades on sand to produce two or three coats. My biggest question is can I get this new lime plaster to adhere to the previous plaster of unknown origin and block. I have heard of "knocking up" or 'throwing'" a first coat- is this necessary? I have never plastered before. Any thoughts?

Asked by Lee Favro
Posted Wed, 02/13/2013 - 20:46

Tags:

1 Answer

Select your preferred way to display the comments and click "Save settings" to activate your changes.
1.
Helpful? 1

Lee,
I'm not a plaster expert. Perhaps a GBA reader will chime in to answer your question.

In the meantime, here is a link to a web page with information that might help you: Cement Plaster Over Concrete Block Walls.

As you might imagine, Portland-cement-based plaster (stucco) is more common than lime-based plaster. Here is another article that might help you: Make it Stick: A Common-Sense Way to Apply Stucco to Concrete Block.

Answered by Martin Holladay, GBA Advisor
Posted Thu, 02/14/2013 - 06:19

Other Questions in General questions

Flat roof insulation

In Energy efficiency and durability | Asked by Angela M | Nov 22, 13

Large structure with sealed attic / fiberglass

In Green products and materials | Asked by W Ahrens | Oct 22, 14

Spray foam over XPS on external wall

In Energy efficiency and durability | Asked by Jeff M | Oct 22, 14

How does the attic fan work? And can you use it in the winter?

In General questions | Asked by Aleasha Jeffries | Oct 22, 14

Double wythe CMU vs. Thermomass

In Green building techniques | Asked by leo kloop | Oct 22, 14
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!