Cleaning & Preparation

A log home or a wood sided home makes a statement. Your design selections are more unique than those of your friends who live in vinyl- or masonite-sided homes. Your wood is an expression of character and beauty that simply cannot be duplicated with synthetic products.

The selection of the finish is only half of the requirement for getting your log home finished right.

The other half is process. Product and Process combine to give the homeowner what they want. How the surface is prepared and how the finish is applied are as important as picking the right exterior finish.

Do It Right The First Time

By the time your new logs are erected or your wood siding is installed, it will not be ready for a finish. There will be boot marks, band marks, road grime and surface contamination that must be removed before that wood is ready for a finish.

What is the best way to clean your log home or wood siding to prepare it for a finish? Soap and water is what your mother used to clean you with when you were new and got dirty. That is the best way to clean up your logs or wood siding and prepare it for finishing. We just use different soap.

The example of why this works is found in your carpet cleaner’s bag of tricks. When your carpets need to be professionally cleaned you hire someone to do that. That person comes out and uses certain cleaning agents to clean and certain cleaning agents to rinse if they are doing a good job. The cleaners are alkaline and the rinsing agents are always slightly acid or pH neutral. The cleaners are applied first to loosen the dirt. Then the water is used to lift the loosened dirt out of the carpet. Then a rinsing agent is used to “neutralize” the cleaner and your carpets look beautiful.

Wood is cleaned in the same way. You would never have a carpet cleaner use bleach because it would damage the carpet. Bleach will damage wood as well.

Alkaline cleaners have ingredients such as trisodium phosphate, sodium metasilicate or sodium orthosilicate and possibly a percarbonate. The ingredients are listed on the label. You don’t need a lot for cleaning new wood. New wood is easily cleaned with a mild solution of an alkaline cleaner.

Don’t use sodium hydroxide (caustic soda) for new wood. Sodium hydroxide is extremely strong and definitely not necessary for cleaning new wood. Follow mixing directions and safety precautions on the label.

It is easier and more efficient if you can spray the cleaner on by using a pump up sprayer or an airless paint sprayer. Apply the mild solution onto the wood liberally. Check to make sure that the surface contamination is loosening before you begin to wash. Scrub stubborn spots with a nylon brush.

Carefully use a pressure washer to clean the exterior wood. Turn the pressure down to avoid damaging the wood. Wash from the bottom up. Rinse from the top down.

Note: Interior Washing
If you are cleaning the interior of a log home make sure you are getting the water off of the sub-floor fairly quickly to avoid causing warping. Use a squeegee and a shop-vac. Watch out for electrical cords being too close to the water or you may get a very serious shock.

Wash one wall or section at a time. After you finish washing the wall or section the wood will be slightly damp. You want slightly damp wood when you apply the brightener.

Apply Neutralizer/Brightener

Acidic brighteners or neutralizers are composed of oxalic, sulfamic, or citric acid and water. Oxalic is by far the most common and poisonous, as well as the least water soluble. You don’t need a lot. The object is to neutralize the remaining cleaner that is still in the wood. Acids do not loosen dirt or surface contamination. They do brighten and neutralize the pH of the wood from alkaline to being just slightly acidic.

Mix a small amount of the acid crystals in warm water. Pour the mixture into a pump-up spray. Spray the brightener/neutralizer onto the damp wood. The brightener/neutralizer works within seconds. After the wall or section is neutralized rinse thoroughly.

Note: Mold and Mildew Sanitizing
Sanitizing for mold and mildew to assure that the wood is free of any potential mold problems that may have not been visible is always a good idea. Call it cheap insurance. Comprehensive exterior wood finishes will inhibit mold or mildew at the wood surface or just slightly below the wood surface as well. If your product representative has a sanitizer that they recommend I suggest using it on every job just to be sure. We will not recommend bleach because it is not as effective as a “systemic” plant specific sanitizer.

Let’s review the steps for cleaning:

  1. Mix and apply the cleaner
  2. Carefully powerwash
  3. Apply the Brightener/Neutralizer to the damp wood
  4. Sanitize against mold, mildew, or algae.
  5. Rinse

This is what logs should look like.

One great aspect of using sulfamic acid as a brightener is that it is much safer and much more soluble than oxalic acid. However, if you apply a sulfamic acid solution to dry pine it MIGHT turn the wood yellow. If that does happen simply reverse the problem with a mild solution of the alkaline cleaner. Within 10 minutes the color will change. Then reapply a mild solution of the brightener to the damp wood and rinse thoroughly.

Interior Wood Cleaning

One trick we use is to use an airless sprayer as a pressure washer when we are cleaning the interior of a log home. Some airless sprayers put out as much pressure as a pressure washer, but the volume of water is about one third and is much easier to contend with.

Using a 3 foot spray pole, a 5:21 airless tip, and an airless sprayer, apply a mild solution of cleaner. Switch to water and wash the interior surfaces. Switch to the neutralizer/brightener and apply the solution to the damp wood. Rinse using the airless sprayer and 3 foot spray pole.

Removal of Band Marks and Nail Marks

One of the toughest types of surface contamination you will find on new wood is a band mark. Band marks are caused by the metal bands or straps wrapped around the bundle of logs or lumber. The manufacturer uses them to hold the logs together during shipping. Sometimes they rust and create a nasty mark on the wood. In this case the acid is your best friend. If band marks are visible after powerwashing and brightening, increase the strength of your acid solution and apply the stronger acidic solution to the mark. Allow the area to dry to see if you got the mark out. It will eventually work the band mark out of the wood. You may want to scrub the acid solution with a nylon bristle brush to work the acid into the band mark.

Sanding Logs

If you sand a log or piece of wood that has been exposed to any kind of sunlight you will notice something. The surface of the wood is slightly darker. The wood just underneath is slightly (15 – 30%) lighter. When you sand you create a “spot”. If you do this at various locations on walls throughout the house you have a problem. “How do you get everything to look the same?”

If you must sand – do it after washing. Do it the day after washing. The cleaning methods we outlined will make the logs or wood surfaces “lighter” for a short period of time. If you have to sand after cleaning the contrast will not be nearly as noticeable. Carpenters always want to sand first. Ask them to let you clean first and then sand only if necessary.