Plaster Wall Restoration

DEAR TIM: My daughter purchased an older home with plaster walls. There are numerous cracks in the walls and ceiling. The plaster appears to be sound. Should she skim over the existing plaster? Will the cracks reappear? Should she use the ready mix compounds that are sold in the large buckets? Is this a DIY'r project we can tackle? N. A.

DEAR N. A.: Ahhhhhhhh! Your daughter is blessed to have old plaster in relatively good shape. It is, in my opinion, the premier wall finish material. Working as a team, you and your daughter will be able to restore the walls. It will take a moderate amount of effort. Hopefully, one or both of you has good hand eye coordination.

Let's talk first about the cracks in the plaster. My guess is that in many locations wall cracks extend from the corners of doorways, windows or arches. Ceiling cracks are often random in nature. You should be able to repair many of these cracks successfully. Some, however, may continue to plague you. Here is why.

Some of the wall cracks may be stress release points. Houses tend to develop joints much like our elbows and knees. Seasonal changes in humidity can cause a house to flex at these joints as the framing lumber behind the walls and ceilings expands and contracts. The only defense when dealing with these cracks is to attempt to maintain as constant a level of humidity as possible within the house. This is often tough to accomplish.

There are several ways you can tackle the crack repair process. One method I have used with great success is to treat the cracks like new drywall seams. You tape over them using an adhesive fiberglass mesh tape or a paper tape. Successive layers of joint and topping compound disguise the repair. A final skim coat over the entire wall fills dimples, hairline cracks, and other imperfections.

Another method is to apply large sheets of thin fiberglass mesh over the entire wall or ceiling. The entire surface is then skim coated with joint compounds which hide the cracks and the mesh.

The ready mixed joint compounds may not be the best material to use. They are simply buckets of glue and filler. You can buy dry powdered setting type joint compounds that mix readily with water. These compounds contain a mixture of glue, filler, and gypsum. The presence of gypsum allows them to harden much like concrete. Same day wall repairs from start to finish are possible with these magical materials.

The ready mixed joint compounds do not always bond firmly to old plaster. In addition, they produce a somewhat softer final surface which may scratch or ding more easily. The setting type joint compounds can be mixed with water and acrylic bonding liquids. This permits them to readily stick to the old plaster.

If you want to avoid dust storms during the final stages of your project, why not buff the walls with a rubber float? These tools are used to grout ceramic tile. If you slightly dampen the dried joint compound and glide the float over the wall surface, you can create a smooth finish that rivals that of the original master who installed the plaster.