Why this skill matters

Most doors and windows that don't work properly aren't broken — they're misaligned.

A door that requires lifting the handle to latch, a window that won't lock because the sash is slightly out of square, a sliding door that grinds on debris in its track — none of these require replacement or a locksmith. They require the equivalent of a 30-minute diagnostic and a few turns of a screw. The gap between "this isn't working" and "I need to call someone" is almost always smaller than it seems.

The preparedness dimension of door and window repair is direct. A household that can close, latch, and lock every entry point after a storm or other disruption is more secure than one with even one compromised entry. The most expensive lock hardware on a door with a misaligned strike plate provides less security than a basic deadbolt on a properly fitted door — because a latch that doesn't fully engage fails under the first application of force regardless of the lock grade.

The strike plate upgrade — replacing short factory screws with 3-inch screws that reach into the structural framing — is the single most cost-effective security improvement available on any door. A standard interior door's strike plate is held in with ¾-inch screws that engage only the door stop and jamb. Three-inch screws engage the king stud. The difference in forced-entry resistance is not marginal.

What you should be able to do

L1 Household Basic

Fix a sagging door — diagnose stripped hinges, fill holes, install 3" screws

Adjust a strike plate so the latch fully engages without lifting the handle

Upgrade all exterior door strike plates to 3" security screws

Clean and lubricate a sticky sliding door or window track

Patch a screen or re-screen a door or window frame

Replace or install a door sweep and weatherstripping

L2 Capable Homeowner

Replace single-pane window glass — remove old glass, order replacement, install and glaze

Re-glaze a wood window frame — replace deteriorated putty around an intact pane

Adjust sliding door rollers so the door glides and seals correctly

Replace a door threshold to restore the weather seal at the bottom

Cross-reference — Weatherization: Door sweeps, weatherstripping, and window caulking are also covered in Insulation & Weatherization. This page focuses on the mechanical repair and alignment skills; that page covers the complete air-sealing audit.

Tools and supplies

Almost everything here comes from the L1 tool kit.

L1 — for door and track repairs

3" wood screws. The single most important item on this list. Replace every strike plate's short factory screws with 3" screws that engage the structural framing. One box handles every exterior door in a typical house.

Toothpicks + wood glue. The repair for a stripped screw hole. Free at any restaurant, $3 at any hardware store. The fix is faster than buying an anchor kit and more durable.

Chisel — ¾" or 1" wide. For enlarging a strike plate mortise. A sharp chisel with a mallet does clean, controlled work. A dull chisel tears.

Silicone spray lubricant. For sliding tracks, hinges, and window hardware. Not WD-40 — silicone stays clean and doesn't attract debris. One can handles the whole house.

Screen spline + spline roller + screening material. A complete re-screening kit costs $10–$15. Screen spline comes in different diameters — bring the old spline to match the new.

L2 — for glass replacement

Heavy leather gloves (not work gloves — leather, for glass handling)

Glazier's points + glazier's point driver or putty knife

Glazing compound (DAP 33 or equivalent oil-based putty)

Window putty knife (flexible blade)

Replacement glass cut to size (most hardware stores cut to order)

Heat gun or hair dryer (to soften old glazing compound)

Common problems — diagnose before you fix

The cause is usually different from where the symptom appears.

Door drags at the bottom or won't close squarely

Almost always the top hinge has pulled away from the jamb — the screws have stripped the soft wood of the door stop. Close the door and observe: if the top is farther from the stop than the bottom, the top hinge is loose. Tighten; if screws spin, fill the hole and re-drive with longer screws. Seasonal wood swelling is the secondary cause — a door that drags only in summer may not need repair, just a note in the maintenance binder.

Latch doesn't engage without lifting the handle

The latch bolt is hitting below the strike plate opening — door has settled or strike plate was installed slightly high. Use the chalk transfer test to confirm. Fix: move the strike plate down or enlarge the hole, whichever is smaller. A 1/8" chisel pass at the bottom of the opening is usually enough. If the bolt is hitting significantly below: move the plate and fill the top of the old mortise with wood filler.

Window won't lock — sashes won't align

On double-hung windows: the upper and lower sashes must be in contact for the cam lock to reach its keeper. If there's a gap between sashes when both are closed, the window frame has racked or the upper sash has dropped (broken sash cord or balancer). On casement windows: a misaligned keeper or a latch arm that's bent — often from being closed against a screen. The sash latch hardware is replaceable at most hardware stores.

Sliding door grinds or won't slide smoothly

Primary cause: debris in the bottom track (sand, small stones, pet hair). Secondary: rollers that have adjusted down over time and are riding too low in the track. Tertiary: worn or bent rollers. Clean the track thoroughly before adjusting anything — debris-caused grinding is often resolved with cleaning alone. Silicone spray after cleaning completes the fix in 90% of cases.

Broken window pane — single vs. double

Single-pane glass in wood frames: re-glazeable by a homeowner. Double-pane (insulated glass unit): condensation or fogging between the panes means the seal has failed. The insulating value is gone. Replacing requires either the IGU alone (if the sash accepts a replacement unit) or the full window. This is typically handled by a glass company — the measurement and ordering is specific to each window manufacturer.

Step-by-step repairs

Five repairs in order of frequency. The door latch and hinge fixes are the ones that affect security most directly.

L1

Fix a sagging door

The stripped-hinge-screw repair. More than half of sagging door complaints have this as the root cause — the top hinge has pulled away from soft jamb wood. The fix holds for decades.

The toothpick fill: Works because wood glue bonds to the existing wood fibers and the toothpicks fill the stripped void. The repaired area is often stronger than the original. Let it dry fully — 4 hours minimum before driving the screw.

1Diagnose the hinge. Open the door and look at each hinge — is the hinge plate sitting flush against both the door and the jamb? A hinge that's pulled forward indicates the jamb screws have failed. Try tightening every screw. Screws that spin freely without tightening have stripped the wood.

2Fill the stripped holes. Dip 3–4 toothpicks in wood glue and push them into the stripped hole. Break or cut them off flush with the wood surface. Allow to dry completely (4 hours, overnight is better). The wood glue fills the void — the screw has new material to bite.

3Drive the replacement screws. For the top hinge especially: use a 3" screw rather than the original ¾"–1" screw. The 3" screw passes through the door stop, through the door jamb, and engages the king stud behind — the actual structural framing of the wall. This is what permanently fixes a sagging door.

4Close and test the door. Does it swing closed and stay closed? Does it contact the stop evenly on all sides? If it still binds at one corner: identify which corner by running a piece of paper around the closed door — where the paper drags is where the door contacts the stop.

5If the door still binds after hinge repair: wood swelling from humidity is the next cause. Check whether the binding is seasonal (worse in summer, better in winter). Light planing or sanding at the binding point is the fix — do it sparingly, as wood will contract again in dry conditions.

L1

Adjust the strike plate and upgrade to 3" screws

Two repairs in one: aligning the latch bolt with the plate opening, and replacing the factory screws with 3" screws that actually engage the structural framing. Every exterior door should have this upgrade regardless of current alignment.

1The chalk test. Rub chalk, lipstick, or eyeshadow on the latch bolt face. Close the door and push it shut firmly. Open and examine the strike plate — the chalk shows exactly where the bolt contacts the plate. If it contacts below the opening: the bolt is hitting the plate face below the hole. If it contacts above: hitting above.

2If the bolt barely misses (by ⅛" or less): enlarge the strike plate opening with a chisel. Hold the chisel at a low angle and take small controlled passes from the edge of the opening in the direction the bolt needs to travel. Test after every few passes — a little goes a long way.

3If the bolt misses by more: move the plate. Remove the strike plate screws. Chisel the mortise (the recess the plate sits in) in the direction the plate needs to move. The plate must sit flush — if the mortise isn't deep enough, the plate will protrude and the door won't close. Fill the vacated portion of the old mortise with wood filler, sand flush when dry.

4Install 3" screws on all exterior door strike plates. The standard strike plate has two screw holes. Drive one 3" screw into each hole at the correct angle to reach the framing behind the jamb. You may need to pre-drill to prevent splitting the jamb wood. This is the single most cost-effective security upgrade on any exterior door — $0.10 in screws, 5 minutes, dramatically improved forced-entry resistance.

L1

Screen repair and re-screening

Small holes: patch kit. Larger damage or worn-out screens: full re-screening. Both take 15–30 minutes and keep insects and rain from entering through open windows during warm-weather ventilation.

Small hole (under 3") — patch method

1Use a self-adhesive aluminum screen patch. Center it over the hole. Press firmly on all edges. Bend the perimeter wires of the patch around the existing screen edge to secure — this prevents the patch from peeling off in wind.

Full re-screening a frame

2Remove the frame from the window or door opening. Lay flat on a work surface. Find the spline — a rubber or vinyl cord seated in a channel around the frame perimeter. Pry one corner out with a pointed tool and pull the spline free. The old screening comes with it.

3Cut new fiberglass or aluminum screening at least 1" larger than the frame on all sides. Fiberglass is easier to work with (more flexible, less prone to creasing); aluminum is more durable but harder to handle without creasing. Lay the screening over the frame and hold in place with small binder clips while you work.

4Use the convex (rolling) side of the spline roller to press the spline into the channel groove on one long side of the frame. Stretch the screen slightly taut as you roll — not tight, just enough to remove sag. Do the opposite long side next (pulling the screen taut), then the two short sides.

5Trim the excess screening along the outer edge of the spline channel with a utility knife — run the blade along the outer edge of the spline, holding the knife at a slight outward angle. The spline holds the screen; the excess beyond the spline is waste.

L1 L2 (roller adjustment)

Sliding door track repair

Cleaning the track resolves most sliding door problems. Roller adjustment is the next step if the door still doesn't seal correctly after cleaning. Worn roller carriages require professional replacement.

1Clean the track completely. Vacuum the full length of the bottom track. Use a stiff brush to scrub debris from the corners and the roller groove. Wipe with a damp cloth. Any remaining debris becomes grinding material between the roller and track.

2Lubricate with silicone spray — not WD-40. Silicone stays clean, doesn't attract dust and pet hair, and doesn't break down rubber components. Spray the bottom track and the top track channel. Wipe away any excess that would transfer to the floor when the door opens.

3Test before adjusting. Slide the door back and forth after cleaning and lubricating. If it slides smoothly: done. If it still grinds or if there's a gap between the door and the frame at the top or bottom when closed: adjust the rollers.

4Adjust the rollers (L2). Locate the adjustment screws — typically at the bottom corners of the door panel, accessible through small slots or holes in the face of the door frame on the interior side. A Phillips head screw inside each hole: clockwise raises that corner, counterclockwise lowers it. Raise or lower each corner until the door seals evenly at the top and bottom when closed, and slides without resistance.

L2

Replace single-pane glass

For single-pane glass in wood windows or storm windows. Order glass cut 1/8" smaller in each dimension than the measured opening — glass that fits tightly cracks. The glazing compound needs a full week to cure before painting.

1Safety first: heavy leather gloves throughout. Remove broken glass carefully — press inward from the outside, working from the top down. Collect all glass immediately in a cardboard box, not a trash bag. Set the window horizontal on sawhorses if possible — working on a flat surface is safer and more accurate.

2Soften and remove all old glazing compound using a heat gun or hair dryer. Warm the compound until it's pliable, then scrape with a stiff putty knife. Remove all the old compound down to clean wood. Remove the glazier's points (small metal triangles) with pliers.

3Measure the rabbet (the L-shaped groove the glass sits in) opening in both dimensions. Subtract 1/8" from each measurement — this allows for thermal expansion and installation tolerance. Take the dimensions to a hardware store or glass shop for cutting. Most cut glass while you wait.

4Apply a thin bed of glazing compound around all four sides of the rabbet before setting the glass — this cushions the glass against the hard wood frame and seals the back edge. Roll a rope of compound between your palms and press it into the rabbet, or apply from the can with a putty knife.

5Set the glass into the compound bed, pressing gently to seat it. Install glazier's points: push one every 6–8" along each edge using the tip of a putty knife. The points hold the glass in the frame; the compound seals it.

6Apply glazing compound over the glass edge at a 45° bevel — running from the wood rabbet to the glass face. A wet putty knife pulled in one continuous stroke produces a clean bevel. Smooth any tool marks. Allow to cure 7 full days before painting. Prime the cured glazing compound before applying finish paint.

Emergency and disruption application

Doors and windows as the security and weather baseline.

After a storm or break-in

A door that won't latch after storm damage or a forced entry needs temporary securing. Options: drive wood screws through the door into the frame at three points (emergency — not reversible without repair), install a security bar under the handle, or add a temporary hasp and padlock on the frame. A broken window can be boarded with pre-cut plywood panels (see Carpentry Basics) until glazed. Document the damage for insurance before any repair.

Strike plate upgrade — do this before any disruption

Replacing every exterior door's strike plate screws with 3" screws is the simplest and highest-return security measure in this category. It costs under $5 per door and 10 minutes each, and it converts a door that fails at the frame on the first kick into one that is dramatically more resistant. This is the pre-season door preparation that belongs in the same routine as smoke alarm testing and generator exercising.

Storm prep — fully operational before season

Any door that doesn't close fully, latch correctly, or lock is a weather and security vulnerability during an extended disruption. A window that won't lock can't resist wind pressure or provide security when circumstances change. Address these before storm season rather than after — a sliding door grinding on debris is a nuisance in fair weather and a failure point when conditions make it harder to manage.

Mandatory section

When to call a professional.

Door and window repair has wide homeowner territory — but several situations are outside what basic tools and skills address efficiently.

Door frame that has shifted or been forced

A door frame that has been kicked in or damaged in a forced entry often shows no visible frame damage but has split at the king stud connection internally. Re-hanging the door doesn't address the structural frame failure. A carpenter or door specialist repairs the frame correctly before re-hanging.

Rotted sill, threshold, or window framing

When the wood framing around a door or window has rotted — the sill, the jack studs at the sides, or the header above — the window or door can't function correctly until the framing is replaced. Repairs to the door or glass without addressing rotted framing produce repairs that fail again quickly.

Double-pane window glass replacement

A double-pane window with condensation between the panes has a failed insulated glass unit (IGU). Replacing the IGU requires precise measurement to the sash manufacturer's specification, the correct glass thickness and spacer, and ordering from a glass supplier. A glass company handles this efficiently; homeowner replacement of IGUs is technically possible on some windows but rarely worth the attempt.

Sliding door roller carriage replacement

Adjusting rollers is L2 homeowner work. Replacing a worn or broken roller carriage — the assembly that holds the rollers and allows adjustment — requires removing the door panel from the track, sourcing the correct carriage for that door manufacturer, and re-hanging. A sliding door technician does this efficiently and with the correct parts.

Practice project

Test and fix every door latch in the house — this weekend.

Time: 2–3 hours depending on house size. Materials: one box of 3" screws ($5), toothpicks + wood glue ($3). Outcome: every door closes correctly, every strike plate is security-upgraded.

1.

Walk every door in the house. For each one: try to close and latch without force. Does it close squarely? Does the latch engage on first push? Does it require lifting the handle? Record any that fail one of these tests.

2.

Check every hinge on problematic doors — try tightening each screw. Any that spin freely get the toothpick-and-glue treatment. Let dry before reinstalling the hinge screws.

3.

On all exterior doors: replace strike plate screws with 3" screws regardless of whether alignment is currently a problem. This is the security upgrade — 10 minutes per door, done once.

4.

For any door that still doesn't latch correctly after hinge and strike plate work: use the chalk test to identify exactly where the bolt is hitting, then chisel or move the plate as needed.

Next project: Walk every window and sliding door. Do they all close fully and lock? Clean sliding tracks and lubricate with silicone spray. Repair or note any broken hardware. Add a maintenance binder entry for any screen that needs replacement before next warm season.

Recommended resources

Books, resources, and the credential.

Books

Doors, Windows and Skylights (Fine Homebuilding editors) — the best focused reference on all aspects of residential doors and windows, including alignment, hardware, glazing, and replacement.

The Complete Photo Guide to Home Repair (Black & Decker) — strong section on door and window alignment, with photo sequences for hinge tightening and strike plate adjustment.

Free resources

YouTube — This Old House door and window episodes: The hinge tightening and strike plate adjustment sequences are particularly clear — the physical technique for using a chisel in a mortise is worth watching before doing.

Community college carpentry programs — door and window installation is a module in most residential carpentry certificates. See your state's Learning page.

The credential

No specific credential is required for homeowner door and window repair. Locksmiths (licensed in most states) handle lock hardware beyond basic replacement and deadbolt installation. Window glass replacement is unlicensed in most residential contexts; commercial glazing work falls under glazier trade licensing.