Beetles in Wood Floors

It is very difficult to control powderpost beetle larvae** (see A Picture of a Lyctid Powderpost Beetle Larva) once they have burrowed into the wood. It is far easier to prevent new infestations than to treat existing infestations. This is why new installations should be treated with borate. However, there are some things you can do if faced with an infested floor.

** also called woodworms

Treating active beetle infestations

New damage occurs slowly so you have time to make good decisions. It is possible that a small infestation will "burn itself out" and no new emergence holes will occur after a few years. In this case very little structural damage will probably occur. A few holes can be considered "patina" or they can be patched the next time the floor is refinished.

Large infestations, however, can cause significant damage to the internal structure of the flooring that may actually lead to failure of the floor surface. If the surface fails, infested sections of the floor will need to be replaced. In addition to floor damage, emerging beetles may infest other, unfinished hardwood (oak, maple, ash), in the home. Softwood (Douglas fir, fir, pine) used for structural framing is generally not affected by beetles that emerge from hardwoods.

There are several different approaches that you can use when confronted with an infested floor. Many times simple "watchful waiting" is the best approach. Mark existing emergence holes so you can track new holes if they occur. You may find that the infestation stops on its own or is so slow that no repair is needed.

Another option is to sand the floor down to bare wood, apply a solution of borate insecticide, such as Timbor or Bora Care, then refinish the surface (see Related Articles below). There is some evidence that this surface treatment will control any beetle larvae within about 1/4" of the surface. Adults emerging through the treated surface will die. This treatment, however, does not eliminate larvae that are deeper but makes sense if the floor needs to be refinished anyway.

The most expensive approach is to "tent and fumigate" the home (see What is Structure Fumigation?). This involves placing a tent over the home so that an insecticidal gas, or hot air, can be pumped in. If done correctly the treatment usually eliminates the infestation. However, tenting and fumigating is very expensive and must be performed by an experienced pest control firm. In the end you must balance the cost of treatment with the costs of potential repairs down the road. My own first choice is always "watchful waiting" and prepare to replace flooring if serious damage occurs.

With any approach you should obtain some replacement flooring from the manufacturer in the event that a section of the floor fails. Depending on circumstances you may also try to secure funds from the manufacturer to pay for repair labor, since the floor may have been infested when it was installed -- discuss this with your legal advisor.

+ A List of Insects That Damage Wood

+ What is Timbor Insecticide?

+ What are Bora Care & Shell -Guard?

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