Rotted Exterior Door Frame Splice Repair

A new section of jamb is installed to to repair the rotted door frame. This project is continued from How to Repair a Rotted Exterior Door Frame.

Rotted Exterior Door Frame Splice Repair

I purchased a new exterior door frame leg (door jamb) to cut off the end for the repair splice:

Exterior Door Frame Leg - Back Side

Exterior Door Frame Leg – Back Side

The front side of the new jamb. This door jamb has sill plate bevels on both ends so there wasn’t the left- or right-hand only part issue:

Exterior Door Frame Leg - Front Side with Weather Strip

Exterior Door Frame Leg – Front Side with Weather Strip

I measured and cut the end off the new door jamb to make the repair splice using the miter saw for precision cuts. The brick moulding must be removed because the new piece has to be inserted from the front of the wall into the pocket:

Rotted Exterior Door Frame - Fitting Splice Repair Section

Rotted Exterior Door Frame – Fitting Splice Repair Section

Shimming

Door jambs are shimmed during the original installation to align the frame. The repair splice therefore sits too deep out of alignment with the main jamb:

Rotted Exterior Door Frame Repair - Uneven Splice Section

Rotted Exterior Door Frame Repair – Uneven Splice Section

Wedge shaped shims would be clumsy on this small piece and it would probably never be even. I decided self-stick flashing tape would be ideal shim material. It’s about 1/16th inch thick and I can build up the thickness with several layers:

Door and Window Flashing Self-Stick Tape

Door and Window Flashing Self-Stick Tape

I cut the flashing tape with scissors and stuck it to the face of the 2×4 wall stud:

Shim Exterior Door Frame Splice Repair with Flashing Tape

Shim Exterior Door Frame Splice Repair with Flashing Tape

Optional: Because it’s a chilly day I gently warmed each layer of flashing tape after sticking it on with an electric heat gun on the lowest setting so it would adhere better. Take care to heat the tape to not more than about 80°F or 90°F while you smooth it out:

Seal Flashing Tape with Electric Heat Gun

Seal Flashing Tape with Electric Heat Gun

Four or five layers of flashing tape was enough to shim the jamb repair splice. The piece now seats slightly beyond the face of the main jamb. This is OK because when I push inward on the splice it’s flush and will be so when nailed it in place:

Exterior Door Jamb Repair Splice after Shimming

Exterior Door Jamb Repair Splice after Shimming

Nail the Jamb Repair Splice

The jamb repair slice is fastened with 2 inch brad nails. You can hand nail it with finishing nails but the work piece tends to bounce out of alignment with each hammer blow, whereas a brad nailer is instantaneous and silky smooth with no jarring:

Rotted Door Frame Repair - Fasten Splice Section with Brad Nailer

Rotted Door Frame Repair – Fasten Splice Section with Brad Nailer

Sand the Jambs

The high spots are sanded smooth with a sanding block to blend the repair slice:

Rotted Door Frame Splice Repair - Sand Edges

Rotted Door Frame Splice Repair – Sand Edges

Window and Door Expanding Foam Void Fill

The void is filled with GREAT STUFF Window & Door expanding foam. Be sure to use only “window & door” foam which is minimally expanding and won’t bow or bend the jamb, sill plate and wall:

Rotted Door Frame Splice Repair - Expanding Foam Void Fill

Rotted Door Frame Splice Repair – Expanding Foam Void Fill

Door Flashing Tape

I cut a long strip of self-stick flashing tape to cover the gap between the door jamb and foam board insulation. Ideally the flashing tape would be tucked under the edge of the lap board siding, however the HardiePlank cement board siding is tightly nailed to the wall and prying it loose would crack it. The best I could was butt the edge of the tape against the siding:

Rotted Door Frame Splice Repair - Apply Flashing Tape

Rotted Door Frame Splice Repair – Apply Flashing Tape

Install New Brick Moulding

I bought a stick of PVC brick moulding and cut it to length on the compound miter saw using the old brick moulding as guide. The brick moulding is fastened with 2 inch brad nails into the jamb and spaced about 8 inches apart:

Rotted Door Frame Splice Repair - Install New Vinyl Brick Moulding

Rotted Door Frame Splice Repair – Install New Vinyl Brick Moulding

The expanding foam is squeezing out at the bottom corner in the above photo. This is good. Use a putty knife to wipe off excess foam while it’s still green and uncured.

Caulk the Seams

The old jamb rotted because the caulk seam failed. It’s important to use a high quality exterior silicone caulk that stays flexible year after year. I prefer GE Silicone II paintable caulk. The paintable version is necessary to paint the jamb and brick mould the same color as a house trim.

I caulked the seam between the sill and jamb, then along the length of new brick mould. Also caulk the along the bottom end of the brick mould. The 3-in-1 caulk tool does a great job finishing the seams:

Rotted Exterior Door Frame Splice Repair - Caulk Seams

Rotted Exterior Door Frame Splice Repair – Caulk Seams

PVC brick mould after caulking the seam with the HardiPlank siding:

Rotted Exterior Door Frame Repair - Brick Mould Caulking

Rotted Exterior Door Frame Repair – Brick Mould Caulking

Install new Door Weatherstripping

After the caulk is fully cured, new weatherstripping is installed. I bought a 7 foot length of Frost King DS7B. It’s simple to install, measure, cut with scissors and press it in the slot of the door jamb.

Frost King Exterior Door Weatherstripping

Frost King Exterior Door Weatherstripping

New weatherstripping and door frame repair splice:

Rotted Exterior Door Frame Repair - Splice Section with New Weatherstrip

Rotted Exterior Door Frame Repair – Splice Section with New Weatherstrip

Door Corner Seal

Door corner seals are self-stick vinyl foam wedges to keep out rain, which caused the paint to peel on the door edge. 4-pack costs less than $5 and is available at the home improvement store:

Exterior Door Frame Corner Seal

Exterior Door Frame Corner Seal

The rotted door frame repair looks good after feathering the splice joint with a 2nd thin layer of caulk and painting:

Rotted Exterior Door Frame - Finished Repair

Rotted Exterior Door Frame – Finished Repair

Take care,

Bob Jackson

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One Response to Rotted Exterior Door Frame Splice Repair

  1. Sandy Smith June 2, 2017 at 10:57 am #

    Thank you for this tutorial. For someone new to having to do home repairs by necessity, the pictures with labels is much appreciated.

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