Plugging Away

Before Don drilled the 3-inch holes in the main floor bedroom’s outside walls where we blew in insulation, he drilled a small hole at each hole’s location and inserted a bent wire to probe for any thing behind the hole (electrical wires, etc.). After determining there were no problems, he started the cut with a hole saw to make it round and the right size, but finished it with a saber saw. The two saws were necessary because, if he finished the hole with the hole saw, the lath would often break loose from the plaster, making the hole saw not work well. Trial and error lead to this trick.

Sequence of steps to plug each hole.

After we blew in the insulation Don striped off a layer of wallpaper that we found on one of the walls. Then he did these things to patch the holes: (1) The first picture shows the insulation now inside the wall, and four holes drilled around the hole. (2) The holes are for screws used to hold two pieces of 1/4-in plywood that were inserted inside each hole, as shown in the second picture. The reason for two pieces of wood was so that each piece would extend a ways to either side of the hole, to hold the lath piece(s) that were cut in half. If this wasn't done, the plaster would be weak on either side of the hole. One piece of plywood would work swell if the wall was sheetrock. (3) The third picture shows how the hole was then filled, using plugs cut out of sheet rock using the same hole saw used to begin the cut the holes. In addition, spacers used behind the sheetrock plug were made out of 1/8-in masonite and 1/4-in plywood, and used as needed, to space out the sheetrock plug (the plaster varied considerably in thickness). The plugs were all glued to the backing plywood using construction adhesive (liquid nails). (4) The last picture shows the final 'mud' (sheetrock joint compound) repair. This was actually several steps of mudding and sanding, because of the shrinkage that occurred where the mud was thick. The end result is a strong repair that should be totally undetectable after painting.

All that took several days, and things were looking good until Sami primed the places were the holes had been. As soon as the wet primmer went on the wall that had had wallpaper, wrinkles and bubbles began to appear. Don thought he had stripped all the paper off before he plugged the holes, but apparently either another layer of paper was underneath, or a layer of the paper had remained behind. The wet primer made whatever it was buckle. Long story short, we stopped priming, and used water to soak the entire wall, and scraped off the second layer. Thank goodness, it came off easily. However, striping this layer messed up the plugs enough that Don had to return to yet another round of mudding and sanding. Lesson learned! We'll test all walls we work on from now on, to see if they have wall paper under the paint.