How to Install Carpentry Trim

Accurate cuts produce clean joints between adjacent trim pieces.

The smooth, continuous lines of a finish carpenter's trim installation appear nearly seamless. Base trim is the most common type of trim and, with proven techniques and the right set of tools, the do-it-yourself carpenter can install base trim and achieve professional-looking results. Learn how to install carpentry trim the right way and put the finishing touches on your carpentry project.

Things You'll Need

• Tape measure
• Base trim
• Carpenter's square
• Compound miter saw
• Level
• Finish nail gun

Instructions

1. Latch a tape measure's tang onto the edge of a wall. Stretch the tape to the opposite end of the wall. Read the tape measure to determine the overall length of the base trim.

2. Hook the lip of a carpenter's square onto the edge of the trim and position the square a couple inches from one end of the trim. Use a pencil and the straight edge of the square to draw a line across the trim's width.

3. Have a partner hold a tape measure's tang on the line. Stretch the tape the across the trim until you reach the desired overall length of the trim piece. Use a pencil to mark the measurement's position. Hook the lip of a carpenter's square onto the edge of the trim and position the square over the mark. Use a pencil and the straight edge of the square to draw a line through the mark and across the trim's width.

4. Position the trim against the fence of a compound miter saw. Adjust the saw's blade to the desired angle, such as a 45-degree angle for square corners or flat for butt-joints. Position one of the lines beneath the blade, activate the saw and cut through the trim on the line. Position the opposite line beneath the blade, activate the saw and cut through the trim on the line.

5. Place the trim against the wall and align the trim's ends with the ends of the wall. Lift the trim approximately 1/32 inch to 1/16 inch above the floor.

6. Fasten the trim to the wall with a finish nail gun. Fasten two nails at each end and alternate nail position between low and high throughout the trim's field.

Tips & Warnings

• Overestimate your trim material needs. Mistakes occur and even professional finish carpenters purchase material with waste in mind.

• Fill nail holes with wood putty and sand until smooth. Filled holes may be painted or stained.

References

• Purdue University EPICS Program: Finish Trim
• University of North Texas: Basic Interior Trim