Expert: Bruce E. Johnson - 5/21/2010

Question
Hi,

I am building an art studio and using a/c plywood walls.  Someone put some non paintable sealant caulk at where the pieces of plywood meet when I wasn't around.  It can't be sanded or painted.  My carpenter suggested using drywall tape and compound and then sanding.  He's made some questionable judgements in the past so I decided that I had better check this out with an expert.  Can this method be used and will it be very smooth, like drywall?  Will the tape show or will it crack over time?  Do you have any other suggestions?  Thanks in advance.

Answer
Hi Shelley, well you have a couple of options from what I can see.  You can pull the silicone (I'm assuming it's silicone if it not paintable) caulking out and recaulk with painter's caulk or use a Minwax wood putty to fill the joints.  The painter's caulk will remain flexible but may show up after painting if it is not smoothed out tightly with a putty knife.  The wood putty can be sanded and if done properly can give you a fairly seamless look but it may develop hairline cracks over time if there is any movement in the walls, however a good heavy coat of paint will bridge those cracks and may prevent them from showing up.  Another option is the drywall mud and taping.  I would recommend using fiberglass mesh tape to minimize cracking and because the plywood doesn't have recessed edges as drywall does to help in the feathering process you will have to float out the joints at least a foot on each side of the seam to keep from getting a wavy look to the wall.  One other possibility would be to cover each joint with a thin strip of moulding made for this purpose, you can even do a strip over each wall stud location to give your room a "board and batten" effect and cover your nail or screw holes. I hope this information helps, please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com