Lesson 15: Interior Finishes

As a contractor, you may believe that the structural integrity of the construction is the most important consideration of the job. The client may never see how well the wall was framed, however, interior finishes are an aspect they will see daily. You might want to consider the appearance of interior finishes as your personal signature on the job, since this aspect will be noticed long after the project has been completed.

Unlike new construction contractors, the remodeling professional will encounter a variety of interior finishing situations.  In the remodeling of older homes, the contractor may be dealing with plaster walls. In newer construction, walls and ceilings are most likely going to be finished with gypsum drywall.

Drywall

Drywall is a paper-covered, gypsum-core panel. It is literally  a “dry wall system” as opposed to plaster which is considered a “wet wall system.” Drywall comes in panels and is available in a variety of lengths and thicknesses. Because it was so common for homes to be built with 8 foot ceilings, drywall is available in only one width -- four feet. Two panels, hung horizontally equal 8 feet vertically. The drywall can then be cut from the edge to accommodate the cut-out for light switches located 48” from the floor.

The standard tapered edge of most drywall allows space for tape and joint compound to be applied allowing for the completed job to appear flat and smooth. A good taping job is as important as the quality of the drywall hanging to insure drywall panels are inconspicuously jointed.

The processes and materials selected to achieve a quality job may vary from company to company and amongst installers. Choices include tapes, compounds and fasteners. Tape can be either paper or fiberglass.

Should you use a two-compound system or a setting compound? Joint compound is used to bed the tape and topping compound is used for the final coats. Topping compound is easier to sand, but it is not stiff enough to be used for bedding the tape. Setting compounds use a rapid chemical drying process to allow for quick finishing and create a very strong joint. It shrinks less than other compounds making it ideal for filling deep cracks. Setting compound is an option for an experienced drywaller, but is not ideal for novices as it is more difficult to sand when dry and sets very quickly. 

Nail pops are a frequent customer complaint. Double nailing reduces the likelihood of nail pops. Using drywall screws will minimize the issue. Drywall nails, which are either ring-shank or galvanized, have a concave head. When driven with a drywall hammer, a dimple is made in the drywall. The screw gun should be used with the depth setting allowing the screw heads to be set just slightly below the drywall surface. Whether using screws or nails, the length of the fastener should penetrate the wood beneath the panels a minimum of 3/4-inch. Regardless of whether you are using nails or screws, it is imperative that you don’t break the paper.

Plaster

Remodeling contractors will come across homes where the interior surfaces are plaster. Usually these homes were constructed prior to the 1950’s. Some basic knowledge and terms used for plastering will prove useful. Plaster was typically applied to either a metal or wood lath system. The first basecoat applied over the lath is called the scratch coat. The scratch coat when pushed into the spaces between the wood lath strips would droop over on the inside of the wall and form keys. This would hold the plaster to the wall.The wet plaster was then cross raked or scratched to provide a rough surface so the second layer would bond well. The second layer is called the brown coat. It was typically a coarse plaster mixed with fibers such as animal hair. A thin layer of fine white plaster made up the finish coat.

You may run across older homes with damaged or cracked plaster walls or ceilings. When possible it is preferred to patch and repair rather than removing plaster and replacing with drywall. For tiny holes, a little spackle and a light sanding will do the trick. For a larger area, gently remove the loose plaster back to an area where the plaster is still firmly keyed or attached to the lath. You can then decide whether to use drywall, possibly two pieces to match the thickness, or to replaster the area. If you choose to use drywall, make the hole square to simplify the repair job. Use a utility knife or keyhole saw to cut away excess plaster. Secure the drywall patch to the lath or stud with screws. Do not use nails as pounding may loosen adjacent plaster. The drywall patch should be taped and the edges feathered into the surrounding plaster to create a smooth undetectable patch.

Using patching plaster is another option. It handles very differently from drywall compound and will take a bit of practice to become proficient. It will harden and dry quickly. It also stays put, which is helpful when patching ceilings. If you do a lot of work in older homes, you might find it very beneficial to read up on the techniques of plastering and master this skill.

Pay attention to the finishing work with respect to walls and ceilings. Your customers may be judging the quality of your work by the appearance of these important interior finishes.

Proceed to the test

 

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