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How to Maintain Vigas

F.R.R. Mallory

A viga is a rafter, roofing timber or beam characteristic of Southwestern Pueblo Revival architecture. Traditionally, vigas were used to support the roof on these adobe-style buildings. Today, most vigas are more decorative than functional.

Adobe-style homes with wood viga beams projecting through the walls to the outside.

Often, the beams are rough-hewn log-style pieces where the bark of the tree has been removed. The surface of the log is smooth and sometimes finished with stains and wood finish products to create the look the designer wants and to protect the wood from bugs and rot. Vigas are often made from pine, spruce and fir trees. Maintaining vigas is important to sustaining the architectural integrity of the home and preserving its value.

  1. Examine the viga by placing a tall ladder under the beam. You need to be able to look along the top edge of the viga for signs of rot, bug infestation, water damage or any other problem. Look for water marks, mold, missing caulk, discoloration or other problems with exposed wood resting on the top of the vigas, as these signs can point out viga problems.

  2. Check, repair or replace the roof over any areas with signs of water leakage or damage. Remove any damaged wood around or near the viga and replace it in kind. A replacement in kind means that you identify the species of the wood, the size of the lumber and the installation technique. Remove the old lumber and insert the new lumber.

  3. Scrape a knife along the top of the viga closest to the ceiling or other exposed woods if there are signs of bug infestation, dry rot, or water damage. If the knife scrapes off sections of wood easily, try inserting the knife blade into the beam at a 90-degree angle. If you can easily penetrate the beam, you may have a problem with rotting. Work your way along the beam laterally and vertically to determine the extent of the problem.

  4. Remove small areas of decayed wood using a wood chisel and mallet to reach solid material. Apply a mix of commercial wood fill to the opening. Look for the best product for your specific type of beam in the location where your home is built, under the conditions the beam is exposed to. Most products are like a bondo mixture in consistency and can be applied with a putty knife. Allow the product to harden and then sand it to the original shape of the beam. You can paint or stain the area to match the appearance of the rest of the beam.

  5. Clean untreated vigas using a vacuum cleaner and small brush. Spray or wipe on a wood preservative recommended for the type of wood and indoor or outdoor conditions. Wood preservatives often have a finish. In general, a matte finish will maintain a more rustic appearance and a glossier finish will look shiny.

  6. Examine exterior vigas or viga sections carefully. If the viga is decorative, it may not go through the wall. Look for signs that the viga is pulling away, is rotting, water damaged, split to a point of failure, or has bugs or other problems. If the viga is decorative, you can simply replace the section in kind using the same installation methods used on the original piece. Use a wood protector to help preserve the new piece from failure.

  7. Remove caulk or material where the viga enters the outside wall to determine if a viga is functional. You should be able to see if the beam continues or stops at a bracket. If the viga is rotted beyond salvaging, you may need to hire a professional restoration and replacement company to help you repair or replace the viga. If the viga is in fair condition, clean the beam with a vacuum and brush. Apply wood preservatives and protectants that have a sealer that will help the beam last longer. Some products can be sprayed on, while others will require a paintbrush.


Repair and replace caulk or other materials around exterior vigas that may allow bugs, water or other materials to penetrate the home. Secure any corbels if they have loosened.