This project explains how to fix sagging French doors. The basement patio doors were sagging resulting in a torn weatherstrip on the active door and a 1/2 inch gap in between the two doors. To fix the problem I replaced the hinges with Hager BB1279 heavy duty ball bearing units purchased from Amazon.com. The Hager hinges feature heavy gauge metal and ball bearings that are much better suited for carry the 65 lb weight of the exterior doors.
The job turned out to be a bit more extensive than simply replacing the hinges. When I removed the door, I found more problems and replaced the torn weatherstrip, rotted door bottom and split t-astragal moulding between the doors.
What Causes Doors to Sag
Doors take a lot of abuse and frequent opening and closings. Several things can cause a door to sag, the most common causes are:
- The hinges relax due to metal fatigue – especially the top hinge which has the greatest stress.
- The hinges screws start to work loose.
- The door jamb and/or frame gets twisted as the door swings open and closed.
- The wall has settled and the door frame is out of square.
In my case, the wall sits on the concrete foundation, no wall settling has occurred, and the door frame is square and plumb. What I did find is the prior homeowner attempted to fix the problem by replacing the hinge screws with longer ones sunk into the 2×4 door frame, but this failed to remedy the problem because the top hinge had relaxed (bent) over time due to the 65 lb door weight over 10 years of use. Notice the darker Philips- and square drive screws in the top hinge leaf. It also looks like the hinge has pulled to left by the gap between hinge and the edge of the mortise. These are a tell-tale signs of a failed repair.
The bottom door hinge had obvious signs of repair with mismatched square drive and Philips head screws.
I happen to have small and large square drive bits for my Dewalt cordless drill, but things like mismatched screws are an unnecessary inconvenience. A further sign of a jack-leg repair job. You should always strive to use the same type of screws on a job.
Hagar Ball Bearing Door Hinges
The Hager Hinge Company specializes in door hinges for residential, commercial and architectural applications. I decided to upgrade basic residential hinges on the 65 lb French Door with heavier models, and settled on the Hager BB1279 ball bearing Architectural hinges rated for “medium weight” doors up to 150 lbs.
This is the box of three Hager BB1279 4 in x 4 in satin brass (US4 finish code) ball bearing hinges.
This is the Hager hinge compared to the old hinge that was on the door. The ball bearings in the Hager hinge are highlighted in the red squares. Notice the screw holes in the Hager hinge are countersunk given the heavier gauge metal where the old hinges are not.
End view of the two hinges. Quite a difference in the quality of the construction!
The Hager hinge (bottom) has square hinge leaves and (fortunately) a different hole pattern. The mortise will be recut for the square hinge leaves and the different hole pattern is good because I can sink the screws into virgin wood for greater strength.
I bought 4 inch hinges to match the size already on the door.
Before moving on to the hinge installation, it’s helpful to have an understanding of how door openings are constructed.
Wood Frame Wall and Pre-Hung Door Construction
In the unfinished section of the basement, a pair of metal 6-panel exterior doors opens onto the basement patio which were made by the same company that manufactured the French Doors. The construction is identical except for the single light glass pane in the French Doors.
These doors are “pre-hung” – meaning the doors and hinges are already attached to the jambs. This is indicated by the large red box outline in the photo below. The door unit is set into the 2×4 framed rough opening, plumbed and leveled with shims, then nailed or screwed into the 2×4 frame. The door casing (also called moulding or brickmold) is the decorative finish trim that’s installed around the sides and top of door jamb to cover the gap between the jamb and 2×4 frame.
A closeup of the top right door hinge illustrates the hinge screws do not penetrate the 1 inch door jamb and it appears the door jamb is largely unsupported in this area. The relatively thin door jamb will not withstand the stress over time of a frequently used and/or heavy door. The door jamb will flex and twist – if ever so slightly – but enough to cause the wood screws holding the hinge to work loose over time. The jamb could also permanently warp causing a sagging door. The right door here is the “inactive” door that is locked into place with top and bottom slide bolts and therefore is rarely opened.
The left door is the “active” door with the door knob and dead bolt that gets regular use. The door jamb on this side is “coincidentally” reinforced with a section of plywood. It appears the carpenter was off in his door measurements and only had enough space for a plywood section instead of a full 2×4 jack stud.
To reach the 2×4 framing studs behind the door jamb, I will substitute #12 x 3″ wood screws for the 1-1/2″ long wood screws (left) that are packaged with the Hager door hinge. I found the #12 x 3 inch screws at Home Depot.
The following photo illustrates how the 3 inch wood screws will sink deeply into the 2×4 stud to firmly anchor the door hinges when I install the news hinges on the French Door.
This project is continued in How to Fix Sagging French Doors – Part 2.
Thanks for reading,
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