In carpentry—like in most things in life—the details matter. In the quick tips series, I'm walking through some of the things I've learned in my decades of experience as a master craftsman so you can be more efficient on the job site—and produce better results. 

One of the things that amazes me about the modern era and social media is how easily information gets shared and how much we can learn from it. This is especially true when tradespeople share technique, because it allows us to learn from each other in ways we never had before. In the old days, one generation would pass down trade knowledge and technique to the next through one-on-one interaction by literally showing the student how it’s done. Although that still holds true today, we in the modern era have the added advantage of learning and sharing technique through videos, pictures, and written word in real time. This is an important modern component in learning and applying technique to better ourselves in our craft.

In this post, I’m sharing what I learned from a social media post for fitting base moulding at inside corners. Oftentimes, drywall at the bottom of the wall is irregular—making it difficult to make a tight joint. Because the base will have a tendency to rock against the drywall, it often opens up at the bottom of the joint as the base is pulled in tightly when nailed. So instead of fussing around with shims or caulking, this is a great tip to help save time and add quality when installing base moulding.  

base moulding inside corner

Make two patterns of the base moulding

The first step is to make two patterns of the base about 1' long, with a spacer at the underside representing whatever floor finish is going to be installed. In our case, a ¾” flooring will be installed, and then the base shoe after that. I added a spacer of about one inch. (The base shoe will cover the ¼” gap which will give the flooring contractor room for installation.) I’ve chosen to use a butt and cope joint with this tall base, but this quick tip will work with a miter joint cut as well.

Install a screw and fit the moulding joint

The next step is to fit the base at each corner. Notice how the drywall is irregular in the video, creating a potential joint gap. The base needs to have a positive stop behind it to keep it from rocking, and installing a short screw is the answer. The reason for this is that the screw can be tightened or loosened until the joint fits tightly. The screw can be installed on the inside corner stud or bottom plate.

screw for tight baseboard corner joints

Prep all inside corners first to maximize efficiency

Go around the whole project and fit as many corners as possible before base installation. The idea here is simple: once the screws are set and all inside joints are fitted with the pattern, there is no need to change anything or adjust the saw. All cuts should be set at zero degrees, as they are all the same. This saves time by being consistent and makes for a better joint and better quality.

When it comes to fitting and installing base moulding at inside corners, I used to fuss around with fitting corners properly—which wasn’t very efficient in some cases. It wasn’t until recently that I saw another tradesperson post a small video about how they found a solution to this fitting problem, and I was amazed I'd never thought of it before.

I immediately started using their technique on a recent project and was impressed by how such a little thing could make such a big difference! Not only that, but I was equally enthusiastic about being able to apply a small trick in real time from a social media post from another carpenter whom I'd never met! This just goes to show that no matter how much experience a tradesperson might have, there is always something to learn. Thanks to our modern era and the ease of access to information, there is no excuse for not learning and becoming better at your craft.

how to use screws as an adjustable shim to fit baseboard corner joints