Do your Deck boards have sap or goo oozing out of them❓
If your deck boards have a bunch of goo and what looks like sap coming out of them . Your not alone❗
I want you to know that it is called "pitch" - your deck boards have "pitch".
The goo or " pitch " is usually generically called by most people in my kneck of the woods - "sap".
"Sap" comes from a live tree.
The difference is - "pitch" is the correct terminology to use once the wood is dead.
The reason for this- I did not dig that deep into the subject if I'm being honest ❗😁
I can however shed some light on why it happens.
Typically premium lumber is sent through a process that solidifies this goo down inside the board and that solidification keeps it from ever coming to the surface .
In fact this is one of the major reasons we treat our lumber.
But just like in every industry and every production process. You will have a few that get through with less than stellar treatment. If they catch them , maybe they sell them as lesser grade lumber or send them back through the process.
But if they do not. The wood makes it to your deck project and is installed. All the while you have no idea it has a massive reserve of "pitch" deep in its wood knots and inwards.
That is until the temperature and relative humidity rise and your wood begins to expand and draw in water from the air. As it draws in the water it must make room so it pushes out the stored "goo" or "pitch".
The best thing you can do ❓
Just pull the board and replace it with a better plank.
I recently made a video about this from a deck restoration painting project. Check it out here: