Installing Trim: A Beginner’s Guide

Installing trim just got do-able for beginners! Crown molding, chair rail, window and door casing, and shadow box trim —  Jenny did it all as a complete beginner and she’s sharing what she learned so you can do it, too!

More for you: Ultimate Guide to Wainscoting  –  DIY Craftsman Window Trim (with no angle cuts!)  –  Trim and Molding Tutorials and Tips

Installing Trim: A Beginner’s Guide

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A quick Remodelaholic note: Before your pick up the perfect trim and start cutting, be sure to practice on an inexpensive piece of molding (or scrap) until you have an understanding of how the angles will work. Jenny recommends some resources below, so read up, watch some videos, and practice, practice, practice!
by Jenny Macarthur

When I first opened the instruction manual for a compound miter saw, all I saw were warnings about the appendages one could lose if the saw was used improperly. I was so frightened and so intimidated that three months went by before I tried to use the saw again.

Unfortunately, power tool manuals are written for people who already know how to use the tools, not for DIY newbies like me. A manual won’t tell you the basics like how to release the blade lock. (It took me nearly an hour just to figure out how to do that!).

But I stuck with it. I figured it out and you can, too!
Installing Shadow Box Trim, From Remodelaholic
To complete a large-scale trim project, I (not a professional, just a DIY-er) recommend the following:

1. Research How to Install Trim

When I started my first trim project, I had no experience installing trim.
Before I priced wood or considered what tools I would need or did anything else, I watched several YouTube tutorials. I searched under keyword terms like “how to” and “wainscoting” or “how to” and “crown molding.”
This gave me an idea of what I was getting myself in to. It’s also how I learned to install trim (along with the help of the two books listed below).
Installing Crown Molding And Shadow Box Trim For Beginners, From Remodelaholic

2. Create a Work Space

If at all possible, have a designated work space where your tools are organized and accessible and where there is sufficient room to work comfortably with long and unwieldy pieces of trim.
Tips and Tricks for Installing Trim and Wainscoting -- get your workspace and tools ready!

3. Acquire Tools and Supplies

I found the following tools to be absolutely necessary for my large-scale trim project. Rent, borrow, or buy, but you must have them.
(These tools represent a significant investment. If you’re doing a large enough project, it will be worth it to buy, but for a smaller project, rent or borrow.)
  • A Compound miter saw (a sliding compound miter saw is ideal, but a 12″ regular one will work just fine). I used a Dewalt.
  • 18-gauge brad nailer (for shadow boxes) and 16-gauge finish nailer (for crown molding) and an air compressor. I bought them as a 3-tool Combo Kit and have been very happy with it.
  • Brad nails and finish nails
  • A ShopVac to clean up all the saw dust you’re going to generate. I found an 8-gallon wet/dry ShopVac at Costco.
  • A 24″ level and 9″ torpedo level
  • Measuring tape
  • Multi-purpose protractor
  • Pencil
  • Wood Filler
  • Sanding Sponge
  • Caulk. After trying several, this DAP caulk is my favorite.
  • Caulk Gun
  • A crown molding chart that tells you what degrees to set your saw for cutting angles. I used the extensive chart available in the book Crown Molding & Trim: Install it Like a Pro, but I learned all the practical knowledge I needed for cutting crown molding on pp. 128-137 of the book Trim Complete, which has excellent pictures to accompany the clear instructions.
  • A bag of pre-cut trim scraps labeled with their angles. I cut several different pieces of scrap trim (the ogee molding for shadow boxes and the chair rail molding) in increments by degree to use for figuring out angles. I preferred to use a protractor to measure angles for crown molding, but found that for chair rail and shadow boxes, it was faster to use my scrap trim samples. For example, I cut pieces of scrap chair rail at 15-degrees, 18-degrees, 20-degrees, 25-degrees, etc. Then, when I came across a corner where two walls meet, I’d hold up two pieces of my scrap trim (cut at different angles) until I found the 2 angles that came together for the best fit. That’s how I knew what angles to cut each piece of trim.
  • The BuildCalc app and This Is Carpentry’s tutorial on how to use it. This app saved me all kinds of headaches when designing the shadow boxes. I simply measured the wall and figured out how many shadow boxes I wanted there to be and then entered the numbers into the app to find out the spacing.
  • Trim Wood
  • Ladder or tall step stool

4. Plan Out Every Detail

To come up with a design for my trim work, I browsed sites like Houzz and Pinterest for ideas.

(Remodelaholic note: We also have a post here with lots of wainscoting styles.)

Once I decided what I wanted to do, I measured all the walls and calculated how much wood I would need.

Word to the wise, give yourself plenty of overage. You won’t be able to use the entirety of every piece of trim and you will certainly make mistakes.

If you’ll be undertaking a large, multi-room project like I did, I recommend doing a small room first to get a feel for how much wood you’ll really need (it will be more than the exact measurements) and for how much time it takes.

Installing Wainscot Trim In Small Bathroom, Before And After, On Remodelaholic

Some of the rooms in my home already had crown molding and chair rail, so I simply matched what was already there for the new trim work.
Installing Trim To Match Existing Trim, On Remodelaholic
Installing Shadow Box Trim With Existing Chair Rail, Before And After On Remodelaholic
I priced the wood I needed at Lowe’s and Home Depot and at my local lumber yards. I found I could get the best deal at a local lumber yard and ordered from there.

The lumber yard also delivered (for a fee), which, given the size of my project, was enormously helpful. Store the wood indoors where you’ll be installing it and give it 3 or 4 days at room temperature before using it.

5. Draw on your walls.

I drew every last piece of trim on my wall before making any cuts or nailing anything in place. It’s a lot easier to make adjustments with pencil drawings than with wood.

I measured from the floor to the top of my chair rail molding, making a mark on the wall about every 18 inches. I then used my level to draw a straight horizontal line connecting all the marks so I would know exactly where to place the trim.

Same thing for shadow boxes. I measured then marked where they would go and used my level to draw straight lines connecting all the markings. Also, when I drew the lines, I measured them right then and wrote the measurements on the walls (I double-checked the measurements before cutting any wood.)

When it came time to attach the wood, I could just line it up with the pencil markings (though, at the time of installation, I still double-checked that the trim piece was straight using a level).
Tips and Tricks for Installing Trim and Wainscoting -- yes, it's okay to draw on the walls!

6. Nailing

When it comes time to nail, remember you’ll have to fill each and every nail hole with wood filler. Don’t go crazy, but you also want your trim to be stable and secure.

I found that if I put a nail at each corner (not too close to the edge, though, or you’ll risk splitting the wood) and about every 8 to 10 inches, that was plenty.

Tips and Tricks for Installing Trim and Wainscoting

7. Finishing

The finish work (wood filling, sanding, and caulking) seemed to take as long as the measuring, cutting, and nailing, but it’s the finish work that really makes your trim look lovely.
  • Nail holes. Use wood filler, not caulk to fill your nail holes. Use a light hand with the wood filler as you’ll have to sand whatever dries on your trim. I suggest using a lightly-damp rag to wipe over newly-filled nail holes to minimize sanding later on.
  • Sanding. Sanding sponges are great for carved moldings and most trim work with minimal wood filler to be sanded.
  • Caulk. It will feel like you’ve caulked miles of seams, but do it! It will give you that seamless look where the wood appears to just grow out of the wall.  As mentioned above, this is my favorite caulk (I tried several different kinds over the course of my project). Buy by the case to save money. You’ll use a ton of the stuff!
Get tips for caulking like a pro here.
Best of luck to you on your project. If I can do it, you can!
Installing Crown Molding And Shadow Box Trim, Before And After, On Remodelaholic

I put up hundreds of feet of trim: chair rail, crown molding, and dozens of shadow boxes.

Installing Chair Rail And Shadow Box Trim In Hall, Before And After, On Remodelaholic

(The shelves and mantel around the fireplace in the family room were built by a carpenter, not me).Installing Trim To Update Fireplace, Before And After On Remodelaholic

I did every last bit of the job entirely by myself. I had a general contractor come by to take a look at all of the trim work I did. He told me that if I’d hired him to do the work, he would have charged me at least $10,000. The wood for my entire project cost me about $1,500.

Installing Trim To Two Story Windows From Remodelaholic


Paint colors are Benjamin Moore White Dove (white) and Restoration Hardware Silver Sage (light blue).

Installing Trim For Beginners, From Remodelaholic 


With Sherwin Williams Naval for the dark navy blue

Sherwin Williams Naval Paint Color With Trim In Benjamin Moore White Dove On Remodelaholic

I hired someone to paint it all after I finished installing trim.

Installing Shadow Box Angled Trim, On Remodelaholic

It took about 200 hours over almost 4 months. I started when I was 8 months pregnant and finished when my newborn was about 6 weeks old. I don’t recommend doing it that way. 🙂 However, I love it all and am so glad I worked through my fears and completed this huge project. I love it!

Thank you so much for sharing your tips and your gorgeous home with us, Jenny!

Also check out:

Please pin this for future reference!

A Beginner's Guide To Installing Trim From Remodelaholic

Originally published 07.07.2015 // Updated 04.14.2021

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Jenny enjoys making life more beautiful in the details. For her, there's nothing more satisfying than figuring out how to get it done DIY-style! She dabbles in a little bit of everything . . . home renovation and decorating, graphic design, cake decorating and baking . . . whatever strikes her fancy at the moment. You're welcome to follow along with her DIY adventures on her Instagram account @turnip_greens_sweet_tea

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  1. Hello~ The wainscoating u did in your home looks STUNNING!!!! WOW!!
    We hired a contractor to do it in our DR yrs ago in a home we lived in, but plan to do it ourselves now in our new home…BUT have not been able to find the lumber to make the picture frames. We looked @ Home Depot and a lumber store. Plz advise…
    Thank u,

    1. Hi Diane,
      You might try calling around if you have a local woodshop, or a local frame maker…. or you could look online as well. Best of luck finding what you need!

  2. Did you glue the vertical pieces in the shadow boxes or just nail? If just nailed, are you worried they will come off the walls? Also if you just nailed, did you just nail straight in or on angles?

    Thank you and very beautiful work.

  3. This is so beautiful and inspiring! Can you please share the type of paint finish you used? I was considering a semi-gloss but the paint store was trying to steer me away from that. Thank you!!