Adjusting the sill height on a door is an important part of ensuring proper functionality and fit. The sill is the horizontal piece at the bottom of the door frame that the door rests on. Getting the sill height right is crucial for having the door open and close properly without scraping or hitting the floor.
There are a few reasons you may need to adjust sill height on a door:
- Installing a new door that doesn’t match the current sill height
- Replacing old floors with new floors that are a different thickness
- Fixing sagging or uneven floors that have altered the door sill height
- Accommodating accessibility requirements and door clearances
Adjusting the sill height involves removing the current sill, trimming it, and reinstalling it at the proper height. This requires some dismantling of the current door frame and sill, so it’s best to have some carpentry skills. However, with the right tools and techniques, it can be accomplished by a motivated DIYer.
Page Contents
Determining the Proper Sill Height
The first step is figuring out what the ideal sill height should be for your door. Here are some guidelines on standard sill heights:
- Interior doors: Between 1/2″ and 3/4″ above the finished floor is common
- Exterior doors: Around 7/16″ above the exterior surface is typical
- Garage doors: 1/2″ above the garage floor level is standard
- Accessibility: For ADA compliance, no more than 1/2″ above the floor
These are general guidelines, but you may need to adjust up or down depending on your specific flooring thickness and door size. The goal is to have just enough clearance for easy opening but no so high that it leaves large gaps or interferes with door operation.
How to Measure Current Sill Height
Start by measuring the current height of your sill above the floor. Use a tape measure to measure from the floor surface up to the top edge of the sill. Take measurements at a few points, from the inside and outside if an exterior door. This will account for any unevenness in the floor.
Write down these measurements. This is your current sill height. Now compare it to the standard recommended height for your application. Decide how much it needs to be raised or lowered to meet the proper clearance. This will tell you how much you need to trim from the current sill.
Materials and Tools Needed
Adjusting door sill height is primarily a carpentry job. Here are the basic materials and tools you’ll need:
Materials
- Replacement sill or sill piece to trim down if reusing current sill
- Wood shims for adjusting between sill and framing
- Construction adhesive for bonding sill to frame
- Finishing nails for added stability
- Wood putty for covering nail holes
- Primer and paint for refinishing sill
Tools
- Tape measure
- Pry bar
- Hammer
- Circular or reciprocating saw
- Miter box and backsaw or miter saw
- Drill/driver
- Nail set
- Putty knife
- Sandpaper
- Paint brush
These tools allow you to remove the old sill, make precision trim cuts, and install the new sill securely at the proper height. Having the right tools is key to achieving professional results.
How to Adjust Door Sill Height Step-by-Step
Now let’s go through the complete process of adjusting door sill height, from start to finish:
Step 1: Remove Door and Current Sill
Start by removing the current door from its hinges so the frame is fully accessible. Use a pry bar to gently pull out the door stop molding. This is the removable trim piece that holds the door in place once closed.
With the stop molding removed, you can now slide the door out of the frame. Pull out any remaining nails or screws.
Next, use a pry bar and hammer to gently pull and tap the existing sill piece free from the frame. Pull out all nails to fully detach the sill.
Step 2: Measure and Trim Sill
Place the current sill on a miter saw or in a miter box. Double check your target sill height. Mark the sill where it needs to be cut to achieve the proper height.
Use a backsaw or miter saw to make the trim cut. Make test fits in the door frame to ensure the sill sits at the perfect height. Sand down the cut edge.
If reusing the current sill, apply primer and paint to protect the fresh cut. Or use a new sill piece for the easiest installation.
Step 3: Install New Sill
Apply a bead of construction adhesive along the sill plate in the door frame. Place the trimmed sill in position in the frame, aligning it flush with the sides. Tap it gently with a hammer to adhere to the adhesive.
Use finish nails and a hammer to add extra stability, nailing through the sill into the sill plate behind it. Set each nail head slightly below the surface with a nail set.
Place wood shims between the sill and the frame at a few points to make small adjustments to the sill height if needed.
Step 4: Reinstall Door
With the new sill securely installed, rehang the door back in its frame. Insert shims between the door and frame to adjust the fit and close any gaps.
Reattach the door stop molding using finish nails. Fill nail holes with wood putty and touch up with paint. Test the door open and close to confirm proper operation.
Tips for Adjusting Door Sill Height
Follow these helpful tips for the best results when adjusting sill height on a door:
- Take precise measurements for accuracy
- Use shims to fine-tune sill height
- Check for level and plumb with a spirit level
- Cut test pieces first to confirm proper sill length
- Secure sill with adhesive and nails for stability
- Rehang door and test function several times
- Use finish nails and wood putty for a seamless look
- Consider having two people for easier installation
Taking it slow and double checking as you go will help achieve a professional looking job that functions flawlessly.
Troubleshooting Common Issues
Here are some common problems and solutions for adjusting door sill height:
Door Drags on Floor
– Sill height is too low – Remove and trim sill further to raise it up
Large Gap Under Door
– Sill height is too high – Lower by trimming sill and reinstalling at proper height
Door Won’t Latch Properly
– Misaligned sill plate – Adjust shims between sill and frame until aligned
– Door strike plate needs adjusting – Loosen and adjust plate until door latches cleanly
Uneven Door Operation
– Floor is uneven – Use tapered shims to adjust sill height at problem spots
– Hinges need adjusting – Loosen hinge screws and adjust plates until door hangs evenly
Sill Cracks or Splits When Nailing
– Pre-drill holes for nails – Drill pilot holes to prevent wood splitting
– Use more adhesive – Extra adhesive will strengthen bond if less nails are used
Taking the time to problem-solve any issues will leave you with a door that looks great and operates smoothly for years to come.
When to Call a Professional
While an experienced DIYer can adjust door sill height themselves, it’s best to call a professional for certain situations:
- Door frame is severely out of square or damaged – May require full replacement
- Removing old door frame that is stuck – Avoid prying too hard yourself
- Major problems with uneven floors – Floor repair needed before adjusting sill
- Unfamiliar with using power tools – Improper technique can damage framing
- Unsure of optimal sill height – Pro can recommend best height
- Need door, sill, and frame fully replaced – Easier to have pro install entire new system
Professionals have specialized tools and knowledge for jobs with underlying problems or full door replacements. They can ensure the job is done right the first time.
Conclusion
Adjusting door sill height is an important process to get right. With the proper techniques and tools, it can be successfully completed as a DIY project. Measure carefully, make small height adjustments, and test operation frequently. Fix any hinge, gap, or latch issues.
Follow the steps outlined here to remove the old sill, install a new one at the ideal height, and rehang the door smoothly. Getting the sill perfectly level will help the door operate properly for many years. With a bit of patience and care, you can adjust the sill height on your door and correct any clearance or functioning issues in no time.