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Community and Q&A

Lath and clay plaster getting started

corkydork | Posted in Green Building Techniques on

We have clay on our property, some sand, and I’d like to make our interior walls of a new build wooden lath and clay plaster. Walls are Larsen trusses with cellulose. I have many basic questions such as
-how to prepare the best mix 
-how to plaster on edges
-can clay plaster act as an air barrier
-can we use bamboo fencing or widely available wooden materials for lath instead of metal

Can someone direct me on where to get started or would someone with experience be willing to chat about techniques? Thanks!
-Courtney [email protected]

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  1. Expert Member
    BILL WICHERS | | #1

    Originally set plaster was done over wood slats. I see no reason you couldn’t use wood slats instead of the metal lath usually used in modern projects. You could rip strips of 1/2” plywood, or see if any lumberyards have anything that would be a good fit. Remember that you need to leave gaps between the slats for the plaster to grab on to.

    I can’t help you with the mix as I’ve never tried mixing my own. You’ll need some skill to get a good application, especially if you want a flat finished wall surface. There is a good reason everyone used drywall these days! It would probably be worth hiring someone with the needed skills to work with you on this project, especially if you can find someone who would be willing to work with you with you as an apprentice learning the trade.


  2. walta100 | | #2

    Do you think the ruff surface of the old rough sawn wood lath is important to duplicate?

    Most everything found in a lumber yard today has been planed smooth.


    1. Expert Member
      BILL WICHERS | | #3

      The plaster is supposed to hold on by squishing between the slats and locking against the back. I’m pretty sure a rough surface would help, but I’ve seen old wood slats that seemed pretty smooth to me.

      I’ve fixed a fair bit of crunched wet plaster walls, but I’ve never done an entire wall from nothing. I always use drywall. I don’t know of anything specifically sold to use for wet plaster wood slats, burn maybe there is a specialty product out there somewhere. I would think strips ripped from plywood, or from dimensional lumber (to make 1-1/2” wire slats maybe 3/8-1/2” thick) would work fine. Use a framing blade to get a slightly rougher edge when cutting.


  3. b_coplin | | #4

    If there is an architectural salvage place near you, it might be worth calling to see if they have any wood lath available. There's a store near me that frequently has quite a bit on hand.

  4. Expert Member


    I don't want to discourage you, but one of the things I often see in owner-built houses is they add a really labour intensive task or building material that stalls the project and ends up taking a disproportionate effort for minimal gain.

    Owners of old houses spend often spend a fair amount of their effort when renovating removing lathe and plaster, and replacing it with the much more user-friendly drywall. If it is the look that appeals to you, I'd suggest blue-board with a skim coat of plaster.


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