Things You'll Need
Foam caulking rope
Glass patio doors can open up a room to the outdoors, giving a great view while blocking out the harsh elements. Maintaining patio doors is simply a matter of keeping them moving smoothly and sealed to prevent leaks and drafts. Although periodic replacement of weatherstripping will keep out the wind, attention should be paid to the seals around the glass panes and the outside of the door frame as well. With a trip to the hardware store and a few simple tools you'll have everything you need to recaulk a sliding patio door.
Prepping the Patio Door
Clean the door in question before assessing the situation. Scrub the glass and frame with a solution of detergent and warm water before caulking a patio door. Super fine steel wool can help with stubborn spots on the glass and frame. Make sure to use quad 0, as coarser wools can scratch glass.
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Check to be sure that the door is in good working order, and make any adjustment or repair before beginning caulking. Shifting and movement from loose or ill-adjusted parts can separate caulk joints, wasting time and money spent on caulking.
Scrape around the perimeter of the door on the outside between the siding or brick to remove and loose or crumbling caulk that may be there. Use a whisk broom or brush to remove loose dirt and debris.
Check the glass panes to see if they are caulked; if so, scrape any loose caulk from joints surrounding the glass. If the original rubber seal seems intact, you won't need to recaulk the glass, only the outside frame.
Caulking A Patio Door
Fill any large gaps outside the frame with foam caulking rope—available in hardware or paint department at local home centers—before caulking. Choose a caulk for the outside frame that is rated for doors and windows to match the frame or the brick or siding.
Use the nozzle cutter—located in front of the trigger on your caulk gun—to cut the caulking tube nozzle. Create an opening about the size of the average gap around your sliding door. Use the folding wire probe (typically located at the end and bottom of the gun barrel) or a long nail to create a hole in the foil seal by poking down through the nozzle into the tube. Squeeze the trigger steadily until caulk rises into nozzle.
Fill the gap with caulk by inserting the nozzle into the gap at one corner of the door. Fill the gap with a smooth motion, allowing the caulk to bead up slightly. Work steadily until you reach the opposite corner.
Work the caulk into the gap with a wet finger. Areas where caulking rope were used may require a second coat to completely cover. Repeat with all gaps on the outside of the frame and around stationary window panels opposite the sliding glass.
Caulk the glass only if needed. The rubber seal is designed for long life and additional unneeded caulk is unsightly. Choose a siliconized acrylic latex glazing compound in a matching color. Repeat the same procedure wherever needed. Use painter's caulk on the inside trim if the trim or wall will be painted.