Expert: Bruce E. Johnson - 4/7/2009

Question
QUESTION: In the process of removing a tile backsplash in my kitchen, I realized my walls were constructed of plaster with a rock lath.  I have searched all over the internet on how to remove plaster walls with this cement like material but most are written on how to remove with wooden lath.  I was hoping to not have to actually remove the wall and just be able to tile over it but the plaster is coming off and the cement-like material (rock lath) is crumbling and making a big mess.  What is the best way to remove this so that I can put up new drywall and/or cement board for new tile?  I don't want to remove the entire wall down to the studs, only the part that will be re-tiled.  Thanks for any help.

ANSWER: Hi Jessica, rock lath is basically drywall.  I take a small right angle grinder for jobs like this, with a concrete cutting blade in it and cut a nice straight line through the plaster and the rock lath down to the studs and remove the offending material.  Then I measure the depth of the plaster/lath combination and build the bare studs back up with drywall.  Normally a lath/plaster wall is 1" thick so I will stack a couple of pieces of 1/2" drywall on top of each other to infill the wall,or cement board if applicable.  Then I put the self adhering fiberglass drywall tape over the seams and finish the area as if it were drywall using a setting type of drywall mud 45 or 90 minute (it is marked on the bag)this setting mud is similar to plaster and works well for these projects.  The key though to the demolition is to cut out the areas with a concrete or masonry blade in a saw or a small right angle grinder.  I use a 4 1/2" right angle grinder for all kinds of stuff like this so I keep a diamond blade in it and even use it to cut tile.  These grinders only cost 40 dollars or less and can quickly become a remodelers go-to tool in bathroom and kitchen re-dos.   I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com





---------- FOLLOW-UP ----------

QUESTION: Thanks for the info on cutting out the wall.  Now that I have the wall out I'm trying to decide how to build it back up to match the surrounding wall.  It appears that the wall is approximately 3/4'' thick.  Should I shim the studs and build that up 1/4'' and then but backerboard up or should I get 1/2'' drywall and put 1/4'' backerboard over the drywall?  Thanks for all your help.

Answer
HI again Jessica, That sounds like it will work.. Or you can use some lattice strips to get the 1/4" thickness and use 1/2" backer board.  But you are on the right track.. I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com