When replacing trim or installing new molding, getting clean joints with tight seams can be tricky. Homes are rarely perfectly square, with level floors, plumb walls, and straight lumber. Like a magician, you need to focus on the final appearance over achieving impossibly perfect molding cuts and fits. Follow these tips when installing trim for the best-looking finished product.


    Tools You’ll Need

    Cutting well-fitting joints starts with having the right tools for the job. Investing in quality tools also makes the work go faster and easier. Here’s what you’ll need:

    • Block plane – Use to fine-tune the fit of mitered joints. Plane with the grain in thin passes.
    • Coping saw – For cutting coped joints on inside corners. The thin blade can cut profiles.
    • Eye and ear protection – Prioritize your safety first. 
    • Hammer – Gently tapping joints can close minor gaps.
    • Miter saw – Get one with at least a 10-inch blade. Diablo and Forrest make excellent carbide-tipped trim blades.
    • Nail set – For setting, finish nails below the wood surface.
    • Utility knife – Helpful for trimming away high spots and cleaning up joints.
    • Wood shims – Use thin shims when adjusting the miter saw fence.

    Cutting Miters

    Mitered joints are used on outside corners, like window or door casings. Cutting good miters starts with tuning up your saw. Make a few sample cuts with scrap pieces and check for tightness. Use shims to adjust the fence and blade if needed.

    Cut the mating parts of one side, like a side piece and a matching top piece. Dry fit them together and look for gaps. Small gaps can be closed with a block plane by gently removing material off the long point of the miter. For larger gaps, recut the miter after adjusting the fence with a shim.

    Once you have a well-fitting joint, repeat the process for the other side. 

    Today’s Homeowner Tips

    Avoid forcing joints closed on miscut miters. Leaving a small gap in the back is better than a ragged front seam.


    Making Coping Cuts

    Coped inside corners require a specific technique, but with practice, you can produce seamless joints between baseboards or other trim.

    Inside corners use coping joints, with the end profile cut away so only the front edge touches. Mark the joint location on the end of the board and cut the profile area away with a coping saw.

    Be careful to cut just inside the pencil line. Test fit the joint and look for gaps. If there is a small gap, trace its width onto the board and use a utility knife to trim more away. Tap finished joints gently with a hammer to close minor gaps.


    coping saw
    Image Credit: Canva

    Installing Trim

    Once you have the hang of cutting good joints, you’re ready to install the trim. Work methodically for the best results:

    • Start by test-fitting the longest straight pieces that go wall-to-wall first. Use any leftover material for shorter sections.
    • Work from the inside of the room out. Install casings on windows or doors last after getting the longer sections in place.
    • Apply wood glue to joints and use finished nails to hold in place as you go. Set any popped nail heads with a nail set for a flush finish.
    • Fill nail holes with wood putty once installed. Sand it smooth, then touch it up with matching paint.

    With good cuts and careful tapping and filling, you can get professional-looking results installing trim yourself. Maintaining square joints to minimize gaps is the key.


    So, Is Installing Trim Yourself Worth It?

    Installing trim carpentry takes time and practice, but the results can be very satisfying. The material costs are affordable, making trim a good beginner DIY project. Focus on taking your time, and don’t get frustrated. As your skills improve, your finished product will look crisp and clean.

    Hiring a professional ensures it gets done fast and flawlessly but can cost thousands for an entire house. For many homeowners, a compromise is learning to install simpler base and door casing and then hiring out for complicated built-up crown moldings. Either way, take pride in the details — it’s the fine joints that make the job.


    FAQs About Installing Moldings

    How do I get crisp edges when cutting molding?

    Use a sharp carbide blade and cut with a good face toward the fence. Cut slowly and cleanly for the best edge.


    What angle should molding corners be cut?

    Most trims have a 90-degree angle, requiring 45-degree miter cuts to join properly.


    What causes gaps in mitered joints?

    Misaligned angles from an inaccurate miter saw, corners not being square, or warped lumber can cause gaps.


    Should baseboard molding be caulked?

    Caulking small gaps looks neater but can attract dirt. Wood putty or small precise drywall screws pulled flush often look better.


    What is the easiest molding to install as a beginner?

    Basic door or window casing and baseboard are good starter projects before advancing to more complex trim.


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    Elise LaChapelle

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    Elise LaChapelle is a copywriter with over a decade's experience in the digital space. She specializes in blogging, website content, social media, and e-mail marketing across a diverse array of clients, helping them to connect with their target audience through concise, compelling messaging. When she's not crafting copy, Elise enjoys working out, cooking, and spending time with her husband and two daughters.

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    Amy DeYoung

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    Amy DeYoung has a passion for educating and motivating homeowners to improve their lives through home improvement projects and preventative measures. She is a content writer and editor specializing in pest control, moving, window, and lawn/gardening content for Today’s Homeowner. Amy utilizes her own experience within the pest control and real estate industry to educate readers. She studied business, communications, and writing at Arizona State University.

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