Inspecting Used Doors: Warping, Hinge Mortises, and Bore Sets

Choosing a previously installed door can be a smart, sustainable option when sourced from salvage yards, reuse centers, or online marketplaces in your area. Success depends on more than a nice finish. The door must be structurally sound and compatible with your frame and hardware. Three checks matter most: warping, hinge mortises, and bore sets. Bring a tape measure, straightedge, small square, flashlight, and notes on your existing frame. Also record your door thickness and swing direction in advance so you can confidently evaluate the fit.

Second-Hand Doors Guide: Warping Checks

Warping shows up as bowing, cupping, or twisting. Start by sighting along the stiles and rails from both edges. Place the door on a flat surface, if possible, and see whether it rocks. Next, hold a straightedge or a tightly stretched string along the length and across the width to detect gaps. Small variations may be manageable, but significant twist typically causes binding against the jamb and uneven reveals.

Measure the thickness and note the construction. Solid wood and engineered cores generally resist warping better than older hollow-core interiors, but any door stored in damp conditions can move. Check for cracks at the corners, delamination around panels, or loose veneer. Examine the top and bottom edges; unsealed edges invite moisture, which accelerates movement. If trimming is needed, confirm there is enough material at the edges and that construction allows it. Hollow-core doors usually have limited trimming tolerance compared with solid wood.

second-hand doors information: Hinge Mortises

Hinge mortises must match your jamb for location, size, and shape. Count the hinges and measure from the top of the door to the center of each hinge location. Many interior setups place the top hinge about seven inches down, the second near the middle, and the bottom roughly eleven inches up from the bottom, though installers vary. Exterior units often use three or four hinges. Consistency with your existing frame reduces rework.

Measure hinge leaf size and corner style. Common interior hinges are about three and a half inches; exterior hinges are often four inches. Corner radii vary, commonly around quarter-inch or five-eighths inch, while some are square. Check the mortise depth; it should accept the hinge leaf flush without proud edges. Look for stripped screw holes, crushed fibers, or patched areas. Minor damage can be repaired with toothpicks and wood glue, dowels, or filler before re-drilling, but extensive tear-out may compromise long-term hold.

Second-Hand Doors Article: Bore Sets and Fit

Bore sets determine which locksets will work without modification. Standard modern locksets in the United States typically use a two and one eighth inch face bore and a one inch edge bore for the latch. Backset distances are commonly two and three eighths inch or two and three quarters inch. Measure carefully from the door edge to the center of the face bore to confirm backset, and verify that the latch bore aligns square to the face bore.

If the door includes a separate deadbolt, measure the center-to-center spacing between the lockset and deadbolt. Five and one half inches is a frequent standard on many pre-bored units, but older or custom doors can vary. Also confirm door thickness. Interior slabs are often one and three eighths inch, while many exterior slabs are one and three quarters inch. Your chosen hardware must support that thickness and the existing bore pattern. If bores are oversized or off-center, reinforcement plates or conversion rings may help, but severe misalignment can be difficult to correct cleanly.

Practical compatibility goes beyond holes and hardware. Determine handing and swing. Stand on the side where the door opens toward you: if hinges are on your right, it is right-hand. Matching the swing avoids relocating hinges and latch strikes on the frame. When in doubt, compare to your existing unit and note the hinge side, opening direction, and which room is considered the primary approach side.

Material and surface condition matter for longevity. Solid hardwood and high-quality engineered cores accept refinishing and minor adjustments more readily than thin veneers over soft cores. Fiberglass and steel units are more dimensionally stable but may require specific paints and primers. Inspect for rust on steel skins, crushed edges on molded skins, and panel shrinkage on wood. Look for previous repairs, such as filled hinge areas or non-standard hardware holes, and consider whether those will affect appearance or strength after installation.

Before purchase, check that the door is square. Measure diagonals corner-to-corner; similar diagonal measurements suggest squareness, while a notable difference hints at racking. Inspect stile and rail joints for gaps. For panel doors, ensure panels are intact and not rattling excessively. For glazed doors, confirm the glass is secure, undamaged, and properly bedded.

Installation readiness starts with careful planning. Record your frame measurements: width, height, jamb depth, hinge layout, strike location, and reveal targets. Dry fit the slab to confirm clearances. Interior slabs often need about three millimeters on the sides and top for free movement, with slightly more at the bottom for floor coverings. Exterior units should account for weatherstripping compression and threshold height. Seal all raw wood edges after trimming to limit future moisture absorption.

Finishing and safety checks round out the evaluation. Sanding and repainting can refresh most surfaces, but be cautious with very old coatings that may contain lead. Follow local regulations for testing and safe removal methods if you suspect a hazardous finish. For stained wood, test a small, inconspicuous area to assess whether a uniform color is achievable or if patchy absorption indicates prior damage or incompatibilities.

A measured approach pays off. By verifying that the slab is flat, the hinge mortises align with your jamb, and the bore sets match your preferred hardware, you reduce surprises during installation. Thoughtful inspection helps ensure the reclaimed piece not only looks good but functions reliably once hung, latching smoothly and maintaining consistent reveals over time.