Log Home Restoration: Mill Glaze and Mildew

This log home restoration was actually a newly constructed home left too long to the elements before sealing.

The disadvantage of waiting is obvious. However,  a few things should be considered. First, newly constructed homes are often built with “green logs.” There is also a good chance they were recently milled. What this means to the homeowner is the wood is wet, tight grained and has “mill glaze.” 

All three of these will prevent a sealer from properly penetrating and result in premature finish failure. Oftentimes this is unavoidable due to the manufacture’s building requirements or sometimes bank loan requirements. 

Thats the bad news. The good news is, properly cleaning the logs will eliminate two of the problems. Time is the only way to solve the ”green”, wet log problem.

This log home was left to the elements for over a year. Mildew had covered most of the north side walls and the others had grayed out. In this situation a good cleaning will prepare the logs for sealing. 

We used a solution of 12% chlorine/TSP solution applied with a sprayer starting from the bottom up. Always start at the bottom. If you start at the top and work down, you will end up with streaked logs that are hard to remove causing much unneeded work.  

Once applied, it is allowed to dwell for a predetermined length of time. A light mist is applied to areas that begin to dry so as to keep the solution working. If it dries on the wood, you will have unwanted problems that could and should have been avoided. 

Once the dwell time is met, a pressure washer is used to remove the mildew, mill glaze and dirt. It should be mentioned that the pressure washer is used more for water volume rather than water pressure. A pressure washer in untrained hands can do irreversible damage to wood. Under 1000 psi…. preferably 5oo to 600 is ideal. To give a comparison, the typical car was is around 1500.   

Once the logs have been cleaned and rinsed, the job is NOT finished. I emphasize not because the next step is just as important as the cleaning but more often than not, it is overlooked or just plain ignored for financial reasons. 

The next step is neutralizing the wood.  I like to describe the reason for neutralizing  as……if you have ever gotten bleach on your fingers and tried to rinse it off, you found it very slippery and hard to remove. The same is true when any kind of cleaner or stripper is used on wood. If caustic chemicals remain in the wood, it can and will react with the newly applied finish resulting in poor performance. 

Copious amounts of water can be used to rinse the wood, but unless you test the wood with ph strips, you may or may not completely remove the entire chemical residue. When it is neutralized, it is very easily rinsed off using a small amount of water and you will be certain any chemical residue has successfully been removed. 

As seen in the picture below, (the dark areas are wet wood from recent cleaning) the wood is clean and free of mildew, mill glaze and dirt. After the wood dries (to at least 18% moisture content) it is ready to accept the new finish. 

After Mildew Removal

The neutralizing process is not hard. It does take more time, but the benefits far out weigh that and any associated costs. Moreover, if it will help the finish last longer, surely it is well worth it.