How to Shim a Door for Easy Fixes?

Ever had a door that won’t close, right?

Maybe it scrapes the floor, swings open on its own, or doesn’t lock without a little shove.

A minor fix with a significant impact might be all you need: a shim. These thin wedges are the unsung heroes of home repairs.

From doors and windows to squeaky floors and leaning cabinets, shims can do it all. But not all shims are created equal, and some doors are vulnerable to simple tricks if they’re not appropriately shimmed.

This guide is ideal for homeowners, renters, or DIY enthusiasts with basic tools and a willingness to take on a project.

Shim & Its Different Types

Simply put, a shim is a thin, angled wedge used to fill gaps between surfaces, often when an item such as a door, window, or cabinet isn’t sitting quite right.

By tapping a shim into place, you can quickly realign and steady things. Though small, shims make a big difference.

They help straighten leaning frames, level wobbly furniture or fixtures, silence squeaky floorboards, support heavy installations, and secure plumbing or deck boards.

Shims come in various shapes and materials, each designed for a specific purpose. Knowing the right type makes your work quicker, more precise, and more stable:

Horseshoe Shims: Ideal for leveling kitchen and base cabinets
Construction Shims: Used in framing and general wood projects
Stackable Shims: Adjust thickness by layering multiple pieces
Flat Plate Shims: Support heavy surfaces like stone countertops
Keyslot Shims: Secure brackets and wall-mounted fixtures easily

How to Choose the Right Shim Material?

Choosing the right shim is more than just grabbing a piece of wood. Consider weight, moisture, and the amount of shaping required.

MATERIAL	PROS	BEST FOR
Wood	Easy to cut and shape; inexpensive	Doors, windows, trim, and indoor work
Plastic	Waterproof, strong, won’t rot or warp	Bathrooms, kitchens, and outdoor use
Metal	Handles very heavy weights; durable	Stone countertops, bathtubs, and appliances

Tip: If you are supporting something heavy (like a bathtub), go with plastic or metal.
For trim or interior doors, wood is easier to shape and cheaper to replace.

Materials & Tools Needed to Shim a Door

These are the most commonly used materials and tools mentioned throughout the guide, enough to complete the door-shimming process efficiently:

Shims: The main component; choose wood, plastic, or metal based on location and load
Screws: Used to secure shims and hinge plates
Caulk or Wood Filler: For sealing small gaps after adjustment
Screwdriver or Drill: For removing and reattaching hinges and fastening screws
Level: To check if the door frame is straight and square
Hammer or Mallet: For tapping shims into place
Utility Knife: For trimming the excess shim after installation
Pencil: To mark problem areas (gaps, rubbing, misalignment)

Step-by-Step Guide for Shimming a door

If your door sticks, swings open, or doesn’t close right, a shim can fix it fast. This simple guide shows you how to line it up and make it work like new.

Step 1: Check for Gaps or Door Misalignment

Close the door and inspect all sides. Look for uneven gaps, rubbing, or if the latch doesn’t align with the strike plate.

Focus primarily on the top and latch side. Identifying these issues helps determine which hinge needs adjustment and where shims should be added to correct alignment and restore smooth function.

Step 2: Loosen the Hinge Screws

Open the door slightly and hold it open. Loosen the screws on the hinge nearest the area of concern.

If the door drags at the bottom, adjust the bottom hinge; if it sags or has a top gap, change the top hinge.

You only need to loosen the screws enough to slip a shim between the hinge and the frame.

Step 3: Insert the Shim Behind the Hinge

Slide a shim behind the hinge leaf that’s attached to the door frame. The shim should be thin and shaped to fit snugly behind the hinge without protruding.

Insert it carefully, making sure it sits flat. One shim may be sufficient, but you can layer more if needed, depending on the degree of adjustment the door requires.

Step 4: Re-tighten Screws and Test the Door

Once the shim is in place, re-tighten the screws securely while holding the hinge steady. After tightening, open and close the door to check the movement.

If the door still rubs or the gaps remain uneven, you may need to repeat the process or use a thicker shim to get better alignment.

Step 5: Adjust Other Hinges if Needed

If the first shim doesn’t completely solve the issue, repeat the same process on the other hinges. Sometimes, a small adjustment to multiple hinges gives the best result.

Continue checking the door swing and gaps after each shim until the door closes evenly, without sticking, scraping, or misalignment at the latch or frame.

For a comprehensive, step-by-step visual explanation of how to shim a door accurately and ensure proper alignment, refer to the detailed video tutorial:

Preventing Door Shim Bypass

A misaligned latch or loose frame can lead to the standard credit card trick.

Here are some simple fixes that help secure your door from this type of bypass:

FIX IT TIP	WHY IT MATTERS
Use a deadbolt	It can’t be pushed back with plastic
Align the strike plate	Keeps the latch securely “dead”
Add jamb spacers	Limit door movement
Check to weatherstrip	Prevents the latch from disengaging
Lock both the knob and the bolt	Prevents quick access via the latch

Security Tip: If your door doesn’t have a deadbolt and the latch isn’t tight in the strike plate, it can be popped open with a plastic card. Always use a deadbolt for safety.

Mistakes to Avoid When Using Shims

Shims are simple tools, but using them the wrong way can create new issues instead of solving old ones:

Loose Placement: If the shim isn’t snug, it may slip during installation.
Wrong Material: Wood can rot due to moisture or weight; plastic is a better option in those cases.
No Fastener: Always secure the shim with a screw or nail to keep it from shifting.
Pushed Too Far: Shims are difficult to remove once they have been over-inserted. Tap gently.