Understanding Wood: 7 Things You MUST Know BEFORE You Refinish or Build Your Next Project!

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Something’s gotten in to me.

It’s called the “woodworking bug.”

Ever since I built a DIY bathroom vanity from scratch, I’ve been enthralled with wanting to learn more about wood.

I started out years ago as simply a furniture painter–finding stuff at the thrift store and wanting to get rid of “that ugly wood” without really understanding wood and what makes it unique and how beautiful it can really be.  I didn’t ask myself the question “When should you not paint wood furniture?” Instead, everything got a coat of paint.

But after attempting to build this vanity from scratch, a lightbulb went off inside my head:

How in the world could I build things from scratch without knowing diddly squat about wood??

How could I get good results if I had no fundamental understanding of the nature of wood??

How could I do projects and expect to teach you guys what I’ve learned and achieved if I am doing it all wrong??

The biggest lesson I learned while building this vanity is that you must understand wood before you try to build with it or refinish it.

Otherwise, you get crappy results, waste your time, and waste your money due to screw-ups.

And I know that wasting money and time is one of the biggest struggles that we all face with DIY.

So once you understand the basics of wood, then you’re more likely to do successful projects, because you’ll be able to anticipate the challenges and come up with solutions!

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7 Things You MUST Know About Wood Before You Build or Refinish a Project - Thrift Diving

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Woodworking Show
Must-Know #1: Wood Is Constantly Moving
Must-Know #2: You MUST Consider the End Grain of the Wood!
Must-Know #3: Barometric WHAT??!
Must-Know #4: Know Thy Wood
Must-Know #5: Don’t Build Something In One Place and Then Move It To Another
Must-Know #6: Check the Moisture Level
Must-Know #7: You Should Use a Pre-Stain
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Understanding Wood: 7 Things You MUST Know About Wood BEFORE You Refinish or Build Your Next Project!

Each year an awesome woodworking show comes to Baltimore, Maryland. The first time I attended I walked away with seven “aha” moments and lessons learned about wood and refinishing, which I’m sharing in this post.


Understanding Wood - Things You Should Know Before You Refinish or Build Furniture


There was one paid seminar I attended called Understanding Wood with Ron Herman.


Understanding Wood - Things You Should Know Before You Refinish or Build Furniture - Thrift Diving Blog


It was pretty funny because I was the “atypical” student in a room full of men that looked like this (yes, faces blurred as to not to offend my fellow woodworkers. LOL):


Understanding Wood - Things You Should Know Before You Refinish or Build Furniture - Thrift Diving Blog 1


But I was just as excited to be there and ready to learn!

Here are some important things I learned that you should save and make note of before you do your next project!

Must-Know #1 – Wood is Constantly Moving

I’m really quite a dummy when it comes to understanding that wood is constantly moving due to changes in moisture.

I’ve always known that you should let wood flooring acclimate to your room by leaving it there for a few days before installing it, but I have never really understood why.

And when it comes to building things, I didn’t put two and two together to realize that if you’re building something, the wood should also have time to acclimate to the room in which you’ll be using it before you start cutting and screwing it together.

As I learned in the seminar yesterday, sometimes people will move from one part of the country to another and suddenly the veneer on their furniture starts falling off or cracking, and they can’t understand why.

Or maybe they built a project in their basement, where it’s moist, and when the project is done, they bring it upstairs to a warm and dry part of their house where it’s sitting in direct sunlight. Suddenly, the boards start cracking and shrinking.

The reason why is because one part of the country (or house) may be relatively more humid than the other part of the country and wood reacts differently in different environments, even different parts of your house.

I’ve never really thought of how wood changes due to the expanding and shrinking of its fibers due to moisture. But if you’re going to be building furniture or upcycling something where you’ll be adding wood to it, you’ve got to understand this fact so that you know how to account for this movement in your projects!

Wood doesn’t change much in its LENGTH.

However, its WIDTH is where the changes can happen. And some wood change more than others.

This is something I plan to spend some time researching more this year!

Click here to read more about wood movement.

Must-Know #2 – You MUST Consider the End Grain of the Wood!

The only thing I’ve ever known to do when picking out wood for projects is to make sure they’re straight.

You know– lay it down all over the aisle of the home improvement store and block customers’ paths, trying to determine if the board is stray or crooked. 😉

But I had no idea that I should be checking the end grain of the board!

I honestly thought that all wood was…..well…..equal. I feel so stupid for admitting that.

I never thought much about the big tree from which it was cut.

But it does matter.

First of all, look at these boards that the instructor from the seminar yesterday passed out to us.

Notice how the one on the left has rings on its end that looks like a rainbow or a smiley face? Well, that kind of board is called plain sawn (also known as flat sawn). This type of board shrinks more than the other types of boards, which could be a big “uh oh!” for your project.

The middle one looks like a rainbow that was sliced in half, with 45-degree lines. I learned that’s called rift sawnThis board is pretty stable and won’t shrink as much. This is the preferred type of board that people want to build with.

And the one on the right is more straight up and down. That’s called quarter sawn. Those can also be pretty stable.


Understanding Wood - Things You Should Know Before You Refinish or Build Furniture - Thrift Diving Blog 3


Understanding Wood - Things You Should Know Before You Refinish or Build Furniture - Thrift Diving Blog 4


So what does this even mean??

Well, it means that when the wood was cut, it was cut from the tree one of three ways.

And depending on how a board is cut, the board will shrink and move in a certain way.

(UPDATE: And be sure to read the comments section, too, because one reader pointed out that wood LOOKS differently depending on how it’s cut. Often times you can look at a board’s face and be able to tell if it’s plain sawn, rift sawn, or quarter sawn.

You must know which kind of board you’re using or else you can screw up a project that you spent so much time on.


I know, I’m just as shocked as you. I had no idea!

The basics are this:

  • Plain sawn (also known as flat sawn) boards are known to shrink more and bow unevenly, plus you can see more of the rings of the wood.
  • Quarter sawn boards shrink only half as much as plain sawn boards, and will not bow and cup since it shrinks evenly. You also see straighter grain, and you may see something called ray lines that look like stretch marks.

So imagine deciding you’re going to make a cute little table, and after some time, you notice the boards on top bowing. Wouldn’t that suck?!

Instead, you may want to use rift sawn boards or quarter sawn boards, depending on the project.

Again, this is something I’ll spend more time learning about and will update this post with more pictures and videos, to be a good resource.

The more you learn about these three types of boards, the more you realize that each one of them are good for certain types of uses, depending on how it reacts to the environment.


Understanding Wood - Things You Should Know Before You Refinish or Build Furniture - Thrift Diving Blog 5


Isn’t this fascinating??

I had no idea it mattered how the boards were cut!!

I found this YouTube video that describes wood shrinkage very well!


Understanding Wood - Things You Should Know Before You Refinish or Build Furniture - How wood is cut from a log - Thrift Diving

Must-Know #3 – Barometric WHAT???

On the back of paint cans and polyurethanes, it always tells you to only use these products when the temperature is X number of degrees, right?

But have you ever heard anything about knowing the barometric pressure before you refinish furniture???? Or before you cut and glue wood??

I’ll admit–I have not.

During the seminar, Ron pointed out that everyone should have a weather station like this in their workspace.


Understanding Wood - Things You Should Know Before You Refinish or Build Furniture - Barometric pressure when refinishing wood. - Thrift Diving


He said that you have to mind the barometric pressure and that you should NOT be cutting, gluing, or adding varnishes to projects on days when the barometric pressure is changing too much.

When the barometric pressure is HIGH we have nice cloudless days. When the pressure is low, we get clouds and rain.

Here is why barometric pressure matters:

  • Sudden changes in the barometric pressure affect the amount of moisture in the air, which means that if you try to add varnish on a day when suddenly you’ve got low pressure with clouds and rain, you could get a cloudy varnish because water is trapped in your finish.


  • Or if you’re cutting boards with low pressure and moisture in the air, then suddenly the pressure is high and sunny and dryer air, suddenly your boards may be too short because they’ve shrunk!


Are you seriously freaking out by this info??

I know that I am!

I’ve tried to Google “barometric pressure and woodworking and refinishing” but I’m not finding any resources.

So the only thing I can tell you is what Ron suggested: get one of these weather stations (I find them at the thrift store often and love them) and when you’re working on projects, keep an eye on barometric pressure changes.

Wait until the barometric pressure isn’t too high and isn’t too low, and has been stable for a few days before you do things like cut, glue, or add varnish and finishes to your wood!

Must-Know #4 – Know Thy Wood

In addition to knowing whether a board is plain sawn, rift sawn, or quarter sawn, you must know the characteristics of the species of wood you’re using.

(Check out this cool Wood Database to look up your wood type).

For example, when I decided that I was going to build a DIY bathroom vanity, I knew I wanted oak because I wanted to highlight the grain with liming wax (also called cerused oak).

Your big box home improvement stores don’t have a ton of options, so I went with…..well…..red oak! (Click here to learn all about Red Oak).

Little did I know that red oak is very porous, you can literally blow through it like a straw!!! I’m not kidding. You literally can. I tried it. (Just put a skinny piece of red oak in a glass of water and then blow into the water like a straw. You’ll be amazed).

At the woodworking seminar yesterday, Ron, the instructor, passed out pieces of red oak and white oak.

You might not be able to see, but red oak is very porous, whereas white oak has a closed grain and is more waterproof. Red oak also has more shrinkage than white oak.


Understanding Wood - Things You Should Know Before You Refinish or Build Furniture - White oak and red oak are very porous. - Thrift Diving


But did I know this before starting to build my DIY bathroom vanity out of red oak??

I sure didn’t! LOL

Which means I have to be pretty careful about sealing the entire vanity to help keep water damage from ruining it. And even then, there’s no guarantee that my vanity will hold up over time.

It’s said that “ignorance is expensive.” Indeed it is.

And if I had known that white oak was used more for furniture, I would have known that I’d have to get materials from a lumber yard instead.

It doesn’t matter if you’re buying it new or if you’re upcycling it from something else.

The point is to know your wood.

With all the info that’s available online, you can find out anything and everything about wood before you decide to use it! Don’t be ignorant like me and not research the wood you’re using for projects!

Must-Know #5 – Don’t Build Something in One Place and Then Move It To Another

In the seminar yesterday, Ron made a good point.

As I mentioned above, often times people will complete a project in one part of their house, say, a basement, where there is more moisture. So the wood acclimates to that environment.

Then they’ll move it to another part of the house when they’ve completed it.

Only to realize that the environments are totally different.

Which means the wood will act differently, too.

It’s best to let the wood acclimate to the room in which you plan to use it so that you don’t get any sudden changes to the wood which can affect how your project turns out.

When I built my DIY bathroom vanity from scratch, I built it in the bathroom where it was going to live.

Such good information!

Must-Know #6 – You’ve Got to Check the Moisture Level of Wood

Understanding Wood - Use a moisture meter before building with wood - Thrift Diving

This is something I forgot to do before getting starting with my DIY bathroom vanity.

I didn’t know enough about wood to check the moisture level of my wood.

Why is that important?

Well, if you try to build with wood that is too wet, it’s going to shrink, depending on how much that species of wood usually shrinks (different types of wood shrinks at different rates).

Imagine building something that depends on it being 18″ wide (wood doesn’t shrink much in length so you don’t have to worry about length). But because the wood is too wet, maybe it dries to 17.75″. What does that do to your project? Probably ruins it. Probably means you’ve got to start over or go buy another piece of expensive wood.

Get a moisture meter and monitor the wood you plan to build with. Make sure the moisture content is stable before using it.

It’s an area that I am still trying to understand myself.

Here’s a great video to describe moisture and wood movement and moisture levels.

RYOBI makes a moisture meter as part of their Phone Works system that runs via an app on your phone.

But if you want a pinless one, this one seems affordable, too, from Amazon.

Moisture meters should be used to measure the amount of moisture in wood before building - Thrift Diving


Must-Know #7 – You Should Use a Pre-Stain Wood Conditioner

I’ll admit this is something else that I was doing wrong.

I wasn’t using a wood conditioner before staining wood. Not all woods require it, but soft or porous woods (such as pine, poplar, maple, fir, alder, aspen, and birch), definitely require it (do a small, inconspicuous test area first). In this quick video, I demonstrate why this is so important and how to apply it. Be sure to subscribe to my YouTube channel for more videos, by the way:


The way that Ron explained it at the woodworking seminar is that pre-stain seals up your wood to help ensure an even, less-blotchy finish. The reason why blotchiness happens is that some woods have areas that more readily accept stain than others.

With pre-stain, it should provide a nice even base upon which to apply your stain, for less blotchiness.

Click here buy Minwax Pre-Stain on Amazon.

Understanding Wood - Use pre-stain wood conditioner before staining softwoods - Thrift Diving

The video above is the perfect demonstration to show you why pre-stain is important.

But remember–if you’re not working with a soft or porous wood, you probably won’t need it. But I’d still do a little test first.

You can read all about pre-stain wood conditioner on Minwax’s website.

Wood Is Amazing…

Overall, it was a great woodworking show!

I am sure will positively affect the next project I work on that involves wood!

Did you know any of these things about wood??

Which tip did you find most valuable? Leave a comment below and let me know!



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  1. My Dad was a master carpenter and recently passed away. I loved to watch him choose materials for jobs. He taught me to appreciate it. He looked at all the characteristics you’ve mentioned and the grain or “personality” of it. In a bold move, we replaced the marble window sills with maple and stain rather than paint them. I’m still pleased with this decision. Not only can I still see the beauty within the wood, it’s also a wonderful memory of my father. Thank you so much for explaining what he was doing at the lumber yard. (Because he also knew the best lumber yards for certain woods, I know the importance of choosing the right supplies for the project). Again, thank you for the thorough lesson!!!

  2. Great article!! I’m in your shoes and now I know a lot different about how wood actually works. Thanks for your help and experience.

  3. John Schroeder says:

    Awesome post! So clear and informative. You’ve got a new follower here for sure! Thanks for taking the time to write all this out.

  4. I’m just getting started with wood projects. I’m pinning this to read later…just skimming it looks like LOADS of great info. Thanks for putting it in 1 spot!

  5. You are my freaking heart. I must admit i haven’t finished reading your post yet, but everything about this from going to a woodworking class with a group of people like that studying and learning more about your passion of DIYing is so me. Thank you so much for this post. I’m literally supposed to be going to refinish a friends furniture in a few hours and am so glad I found this post. I had no idea that barometric pressure mattered or that wood cut mattered, or that wood could shrink (although I’ve experienced it in my journey-I thought I had just miscalculated). This is mind boggling.

    I’ve always thought grain was for looks and paint vs stain was just on preference. You are freaking amazing.

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