Log homes often continue to seep sap or pitch because the natural resins inside the wood remain active long after construction. Heat, sun exposure, and seasonal temperature changes can draw these resins to the surface, especially in species like pine and spruce that naturally contain higher pitch levels. Even after staining or sealing, sap pockets deep within the logs can warm up and liquefy, causing ongoing seepage over time. This is a normal characteristic of resin‑rich wood and not usually a sign of structural problems.

What to Do About Log Homes That Continue to Seep Sap or Pitch

If you have a log home and the logs continue to seep sap or pitch, you’re not alone. Log home maintenance has some unique aspects compared to the maintenance requirements of other types of home construction. One unique problem log homes present is when sap or pitch from the logs seeps out, becoming visible and unsightly.

We received the following question on our blog about this common problem in log home maintenance.

Why Do Logs in Log Homes Continue to Seep Sap or Pitch?

Question: Pitch or sap is leaking out from my logs. I want to know if there is anything that can be done to keep this from happening.

Answer: We have seen a number of log-sided and full-log homes with real problems with pitch seeping out of the logs. Most are homes built within the past 20 years, and all are made of some species of pine, be it Eastern, White, or Norway pine.  Most of the time, pitch stops coming out after about five years.  Often in these cases, the logs need to be blasted to remove the pitch, and then the logs need to be re-stained.

In extreme cases, pitch can continue to seep out for many years. It is my opinion that this is happening because the stain on the logs is acting as a blocker; as it ages, it starts to fail and break down, and this “blocking” effect goes away.  When this happens, the sap is allowed to flow again.

Here is an article entitled: “Effective Management of Resin Exudation from Eastern White and Red Pine” done by the University of Maine. Just in case you want more information on this and what resin blockers might be able to do, click here for a PDF of this study.