How to Install a Sliding Glass Patio Door

A sliding glass door is a great addition to let in more light and air or act as an eye-catching access to a deck or garden. Whatever the case, here are a few steps to help make it as easy as possible.

Prepping the Existing Wall

  1. Choose the site for your new door. Inspect both sides of the wall and from the attic and basement to make sure there are no heating ducts or other hidden problems with the site. Try to avoid all electrical and plumbing fixtures.

  2. Mark out the door dimensions on the wall, allowing an extra 4 inches on each side to allow for double jack studs (see glossary) and shim space and an extra 7 inches on top to allow for a header (see glossary) and shim space.

  3. Turn off the electricity for this area at the breaker or fuse box to protect yourself from shocks.

  4. Put down dropcloths or plastic sheeting. Have trash containers ready.

  5. Carefully remove all the wall covering inside the borders you marked. Do this by cutting and chipping away plaster or drywall by hand or using power tools. Go slowly to avoid damaging any electrical or plumbing set-ups in the wall.

  6. Remove all insulation, dirt and debris as you work.

  7. Drill marker holes through to the far wall; pencil in lines that show exactly where to remove the wall covering on that wall.

  8. Carefully remove the wall covering on the far wall.

  9. Determine at this point how advanced your skills are with electricity and plumbing. If you have any doubts at all, call in professional help to re-route anything in the way of your new door.

Removing the Old Studs

  1. Be sure to heed these important precautionary steps!

  2. Get a friend to help with the heavy lifting involved here.

  3. Take this step seriously: Brace up the wall you are working on to provide temporary support while the new jack studs and header are put into place.

  4. Make the bracing: Place a 2x6 (at least the length of the new opening you are creating) flat against the ceiling. Place another 2x6 of the same length flat on the floor. Set 2x4 uprights to wedge firmly between the two 2x6 pieces at 2-foot intervals. This brace should be set up no more than 2 feet away from the wall you're working on.

  5. Make sure you have solved any problems with plumbing, electrical or any other obstacles within the perimeter of your door opening - either by fixing them yourself or having a professional do it.

  6. Cut the old studs across the top at the same height as the opening using either a hand saw or power tool.

  7. Pry each stud loose at the bottom of the wall. Set them aside; sometimes they can be used in the reconstruction process.

  8. Remove the bottom plate - the 2x4 or 2x6 that runs along the floor that all the studs sit on. Cut on a line even with the sides of the opening and then pry the piece up from the floor (it will be nailed or screwed down).

  9. Check the surrounding floor covering - if it's very thick, you may have to chisel carefully through it to get the unwanted piece of plate out and not damage the surrounding floor with a saw.

Building the Opening and Installing the Door

  1. Make new full-length studs that will fit against the outside of the studs at each edge of your opening. These can be wiggled into place and attached from inside the opening you have in the wall. (We suggest using 2½-inch decking screws and drilling with a screwdriver bit for this rough-in construction phase. It causes less vibration and possible damage to poorly secured wall coverings.)

  2. Cut two pieces of 2x6 the same length as the width of your opening. Find something ½-inch thick to use as a spacer between the two pieces and then nail them together like a sandwich (2x6 - spacer - 2x6). Make sure all edges are even and flush. This makes the header the same width as the 2x6 studs and makes applying new wall covering much easier.

  3. Fit this header tightly against the bottom of the exposed studs that were just cut off. Secure it lightly in place so that you can get the measurements for your jack studs to fit under each end of the header. (We suggest using 2½-inch decking screws and a screwdriver bit here as well.)

  4. Cut the jack studs to fit tightly between the floor and the bottom of the new header.

  5. Wedge them in place and secure the new full studs to the studs, header and the floor. In the case of a header this wide, it is a good idea to use "double" jack studs, so just cut two more and attach them directly against the first set of jack studs on each side and to the floor and header.

  6. Attach the header to each of the cut studs above. The opening is now complete and ready to have the door installed and the finish work done to the wall.

  7. Installing a sliding glass door is accomplished very much the same way as a single width, pre-hung exterior door only on a larger scale.

  8. Assemble the unit if it doesn't come pre-assembled.

  9. Set the unit in place from the outside of the structure.

  10. Get the unit roughly into position as far as being flush with the wall lines both inside and out. Also make sure that the unit is centered in the opening. You can now mark any carpeting to be removed so that a level, tight, weatherproof seal can be made. For ceramic tile or a hardwood surface, it is easier to build up under the sliding door threshold to bring it to floor level than to remove the flooring.

  11. Remove the unit and ready the floor, doing any cutting or building up that is needed.

  12. Run several heavy beads of silicon caulk along the area to be covered by the unit's threshold.

  13. Set the unit back into position and keep it in place by using a few screws through the threshold into the floor.

  14. Use a carpenter's level and square to shim the unit into place all along the sides and top. Once the sliding door unit has been secured, go back and put screws in each of the provided holes. Remember not to overtighten as it can warp the framework and make for a poor door-to-frame seal.

  15. The project is now ready to have the walls patched and finished and the trim applied. The temporary bracing system may now be removed.


  • Use a dust mask and safety goggles during this phase of the operation.
  • Please remember that bracing up an opening of this size is very important in preventing possible property damage or personal injury.
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