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Restoring and Painting Plaster and Lath Walls

Index

  • The History of Plaster and Lath Walls

    Most homes prior to the Second World War were built with lath and plaster walls, as opposed to the drywall method more commonly used in today's construction. Thin pieces of cedar (called lath) were nailed onto the 2x4 framing, then wet plaster was applied onto the lath in one to three applications.

    Depending on the quality of the original installation and the maintenance of the home, such lath and plaster walls, may be in good condition. With adequate maintenance, they may be fully serviceable and usable. In some cases, layers of wallpaper were applied on top of the plaster for decorating purposes. Since that wallpaper contributes to the stability of the plaster in some instances, its removal could contribute to the demise of the wall covering.

  • Reasons for Preserving Your Lath and Plaster Walls

    While most of us would agree that drywall has numerous advantages over lath and plaster walls. However, certain wall details, such as coved ceilings, are not easily duplicated with drywall. A few lath and plaster contractors do exist, and are available to restore old plaster walls, repair damage, or create the special acoustical effects associated with plaster surfaces. Such plaster work is relatively expensive. However, with continual maintenance it is not usually necessary.

  • Step by Step Restoration

    In rooms where most of the plaster is securely attached and damage is restricted to some blemishes and cracks, the following steps will result in a successful job:

    1. Remove all unnecessary hooks, nails, fittings, and loose or broken trim.
    2. Remove and save electrical cover plates and light fixtures.
    3. Using a four inch putty knife lift off any loose pieces of wallpaper and plaster.
    4. Paint the entire wall surface with a pigmented shellac. This pigmented shellac will reduce the moisture damage from patching plaster and other products used in the restoration process. The pigmented shellac is also a very good primer.
    5. Patch any holes or imperfections in the wall surface using a patching plaster or similar compound. Use a latex caulk to patch thin cracks.
    6. Re-prime all patched areas and inspect for any new areas of bubbling or other damage caused by the patching or priming. If wallpaper bubbles appear, cut them out, re-prime, patch and prime the patched area again.
    7. Once all the wall surfaces have been primed, patched, and re-primed as necessary, latex paint may be used for the final paint coat. It may be necessary to use a texturing additive in the paint, or use a texturing coat under the paint, in order to blend the original and patched surfaces of the wall into one texture. Please note that higher gloss paints show imperfections more than flat paints.

  • Helpful Hints

    • Keep in mind that plaster is a brittle material and that stress cracks and other blemishes are to be expected in plastered surfaces. Such cracks are best dealt with by the use of a latex caulk, which can be repainted when still wet.
    • A common trim detail in homes with plastered walls is a picture rail, designed to avoid putting picture hooks, or other hanging devices into the plaster wall. The picture rail is designed to hang the pictures from this trim piece by the use of hooks and wiring. This rail is usually located a few inches below the ceiling.
    • In all homes, especially in homes with lath and plaster ceilings, special care must be taken when working in the unfinished attic space to avoid damage to the lath and plaster that can be seen below the floor joists.
    • In rooms with heavily damaged flat lath and plaster ceilings, new drywall can be applied directly over the old plaster by attaching the drywall to the ceiling joists, using long drywall screws. Where molding, such as a picture rail, is installed in a corner between the ceiling and the wall, the molding may have to be removed and re-installed after the new drywall has been applied and finished. Covering old plaster walls with drywall may be more difficult, since the thickness of new drywall diminishes the profile of doors, windows and other trim on the wall. A common solution to this problem is the removal of the plaster, and the installation of new drywall directly over the remaining lath.
    • It is always a good idea to review existing, or future electrical needs prior to restoring or repainting existing walls. A skilled electrician should be able to install new electrical wiring with minimal damage to the wall surfaces. However, the possibility of some plaster damage is to be expected, and it is for this reason that such work is ideally done prior to work on the wall surfaces.
    • Many damaged plaster ceilings, especially coved ceilings, are covered with a heavy textured spray in an attempt to correct the ceiling damage. Such textured material does little to restore the integrity of the plaster. This material should also be tested prior to removal, to determine if it contains asbestos.
    • When replacing windows, it would be prudent to purchase replacement windows that fit into the old sash openings. This eliminates the need to take apart old interior and exterior window trim, or cause any damage to the plaster. Most windows are available in various sizes to fit several sash openings.