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Patio Door Installation Tips

Patio Door Installation in bright modern kitchenInstalling your sliding patio door isn't difficult; if you have some basic construction knowledge and the tools you need you can be enjoying the quiet and smooth glide of your new patio door in no time at all. The actual finishing steps will vary depending on your taste and style preferences but the basic patio installation steps are outlined here. We also have professional installers who can do the job for you, so if you're not a handy person we make patio door installation even easier! We've summarized the steps here to give you an idea of the process.

Sliding Patio Door Installation

Step 1. Measure your space carefully.

If you're replacing an existing patio door, the best advice is to remove the interior trim to full expose the space you'll be filling. When measuring the width, you'll want to make sure that you're measuring the distance to the framing that's beside the existing doorjamb. When measuring the height, ensure that you're measuring the distance to the wood that the doorsill is actually resting on. Then let us know your rough sizing measurements and our staff can help you to purchase a sliding patio door that fills that space. Now's the time to decide if you'd prefer a right or left handed opening, as one or the other may improve accessibility. Door transoms are also available if you want to change the style of your entrance.


Step 2. Removing the old patio door.

In order to remove the old door you’ll need to expose the nailing flange: a fin that runs around the perimeter of the door that allows you to nail the door to the framing of the house. Next, remove the sliding portion of the door by sliding it open as far as possible, lifting the door up (watch your back) and then allowing the door to drop to the outside of the track below. Now remove all the nails from the nailing flange (accessible from the exterior) and the door should be ready to lift out of its current position. An extra set of hands to help with lifting the door out is recommended. 


Step 3. Preparing the space for the new patio door.

Installing flashing will keep the door watertight. A peel and stick flexible flashing (e.g. Blueskin) around the perimeter of the door with an overlap in all directions of about 2 inches is always a good option. Ensuring your doorsill is level is important for smooth gliding action, and shims can be used to accomplish this. Whether or not you need top flashing will depend on the amount of overhang on your patio.


Step 4. Installing the patio door.

With your rough opening prepared you can now lift your new door into place. Be sure to pull out the sliding portion of the door to make it easy on yourself. Once the door is in the hole, tack in a few nails through the nailing fin to keep the door into place so it doesn't fall back out! Next, lift the sliding portion of the door into place and lock the door closed. This gives the door some rigidity and also allows for it to take on its naturally rectangular shape. Level the door, shimming where required, and once square tack the rest of the nails into the nailing fin. Check the door for sliding ease and adjust the slider as necessary to improve its glide.


Step 5.  Interior finishing.

Insulate around the door frame using home insulation. Add interior trim and casing accordingly. 

Step 6. Exterior Finishing.

Insulate the exterior to fill in any gaps and trim out accordingly. Often you can reuse the trim that you’ve popped off so be sure to be delicate with removing this at the start!


This outlines the basic steps of patio door installation, and is not intended to be a complete how to guide. It can help you to decide whether or not you feel comfortable doing the installation yourself, or whether you'd prefer professional installation.

Give us a call for a free estimate, and ask what options are available to upgrade your patio entrance.

"Just wanted to drop you a note to let you know how pleased I am with my new windows, skylight and patio door; and the people who installed them. They all look great and perform exactly as promised.The two installers were excellent. They were professional, polite and efficient. When the job was done they completely cleaned up after themselves, and made sure the windows were spotless – you would never know they had been in the house. Thanks again Paul. I am looking forward to replacing the rest of my windows next spring. "

- Mike Thompson, Nanaimo BC

      Better Mousetrap