A sill is that thing you step over (sometimes referred to as a threshold) when you pass through a door opening. You may never notice it, but the sill plays an important role in weatherproofing any doorway that leads into your home. Almost every swinging door has a sill of some sort, with good reason. In order for a door to swing or slide freely, there must be a certain amount of airspace around the perimeter, and therefore, a gap where air and water could conceivably penetrate and enter the interior spaces of your home, especially at the base of the door. A raised sill creates a barrier to keep any water that may collect around the base of the door from entering your home during a driving rain storm. Important, right?

Well now consider your patio door sill. Patio door openings can range from 5 feet to up to 50 feet or more in width and up to 12-feet in height. That’s a lot of wide open space; and patio doors are often positioned on the most exposed elevation of your house. It is important to consider whether you need a raised sill as a water barrier, or if the opening has enough protection to consider a sleek, recessed track system or recessed channel system for your masterpiece of indoor/outdoor living.

For a Bi-Folding patio door you have three sill/no sill options.

1.      A Raised Sill made from aluminum or wood with a built-in weep system to collect water and divert it to the exterior through the front of the sill. A raised sill offers the very best protection from water penetration, but with a 2” tall dam on the interior face of the sill, this thing is hard to miss, and you and your guests have to step over it when passing through the doorway.

2.      A Raised ADA Sill in aluminum with no weep system, which requires a 1″ wide x ½” deep channel be cut into the concrete to install it. Although this option is required in commercial applications and is needed in a home where a wheelchair is part of daily life, this sill has no dam to stop water and no weep system, so is not appropriate where weather exposure is a problem.

3.      A Recessed Channel—this option requires that a 1” wide x ¾” deep channel be cut into the concrete. An aluminum “u” channel is fixed into the cutout and the top of it sits perfectly flush with the finished floor. This gives you the most unobstructed indoor/outdoor appearance and nothing to step over or trip over. A recessed channel has no weep system and offers absolutely no protection against water entering the house, since there is no dam to keep water out and is really only appropriate where rain and garden hoses can never hit this door. Only stone, tile, or other water- resistant flooring material should be used to the inside of any door that does not have a raised sill—never wood, which would be damaged by any water that might find its way into the house.

For a Lift and Slide Patio Door or Multi-Slide Patio Door, you have two options, one with a sill, and one with tracks only.

1.      A Raised Sill made from aluminum or wood with a raised track set into it for each sliding door panel. The raised sill has a 2” dam on the interior so it provides superior protection against water penetration.

2.      A Stainless Steel Recessed Track System that is concealed beneath the finished floor, so the only thing visible after flooring is installed is a ¼” x 1/8” strip of stainless steel for each active door panel. A stainless steel recessed track system is great for openings with no weather exposure, and gives you an almost completely unobstructed floor with no sill to step over, but offers absolutely no protection against water penetration.

Before you purchase your AG Millworks patio doors, your sash and door supplier and builder will help you choose the right sill option for your patio doors and AG Millworks will build your patio doors exactly as you specify them. So what are you waiting for? Let’s get your patio door into production!

Just click here: Match me with a Dealer

This 5-Door Bi-Fold is 15 feet wide and 10 feet tall and all doors fold to the right with a daily door.

Large-scale patio doors that open up entire walls are becoming more popular than ever. And it’s easy to see why people are planning them into their new custom homes. If panoramic views and indoor/outdoor living appeal to you, then read on to learn which type of patio door is best for your home, your lifestyle, and how you might use the door in your everyday life.

Bi-Folding Patio Doors (also known as Bi-Folds, Bi-folds, and Accordion Doors)

Bi-Folds are a series of patio door panels hung from the head jamb and hinged together to slide accordion-style and stack against one edge of the opening or the other (see above). The benefit of a Bi-Fold door is that when the doors are all open stacked to the side, you have only a small part of the opening used because the door faces are stacked against each other. You need a strong header in the opening to install the Bi-Folding door system to, or the doors will not fold smoothly.

If there is a downside to a Bi-Fold door system, it is that the doors fold to the exterior, so the bundle of folded doors will stick outward onto the patio as much as 36.” Bi-Fold door panels can’t be too wide because they hang from the head jamb, so they require a larger number of doors to bridge an opening, and when closed, the door panels sit side by side (edge to edge), which makes for less daylight than in a sliding door system.

Bi-Fold Design Tip: When planning your Bi-Fold door system, be ODD! That’s right, an odd number of doors folding in one direction gives you a Daily Door on one side. Just heading out to the barbecue? The daily door can fold with the rest of the doors, and also serves as a single swinging french door when you don’t want to fold open the entire unit. So think 3,5 or 7 doors for the most user-friendly door system.

Lift and Slide Patio Doors

Lift and slide patio doors are a more massive version of the typical sliding patio door system you may be familiar with. European hardware makes it easy to smoothly slide doors that are extremely wide and thick so you can open up entire walls with the turn of a handle. The doors slide on a staggered track system and “telescope” (pull the door behind it along as   When fully open, lift and slide doors stack directly behind one behind the other, and when closed their stiles (vertical members of the door that block the view) overlap so you have more daylight per door than with a Bi-Folding system.

The downside to sliding patio door systems is that there is always a door or doors covering up part of the opening, even when all the doors are in the fully open position. Another consideration is that each lift and slide door is 2-1/4″ thick, so in order to slide more than a few doors in any direction, you will need a fairly thick wall to accept the sliding door jamb. This wide wall can be easily planned into a new home, but if you are remodeling your existing home, you might have to do some reframing of the wall where the lift and slide is going to go.

Pocketing Lift and Slide Patio Doors

The best possible way to live the indoor/outdoor lifestyle is to have your builder construct a “pocket” in the wall that all of the doors can slide into and hide whenever you want the wall open. Pocketing sliding doors can be ordered with either removable handles or folding handles, so the doors can slide all the way into the pocket and disappear. When you want to close off the opening again, a retractable pull in the leading edge of the first door can be popped out and used to begin sliding the doors out of the pocket.

So, Bi-Fold or Lift and Slide? We’d like to hear how you will expand your world view!

This 5-Door Bifold is 15 feet wide and 10 feet tall

and all doors fold to the right with a daily door.

Large-scale patio doors that open up entire walls are becoming more popular than ever. And it’s easy to see why people are planning them into their new custom homes. If panoramic views and indoor/outdoor living appeal to you, then read on to learn which type of patio door is best for your home, your lifestyle, and how you might use the door in your every day life.

Bifolding Patio Doors (also known as Bifolds, Bi-folds, and Accordion Doors)

Bifolds are a series of patio door panels hung from the head jamb and hinged together to slide accordion-style and stack against one edge of the opening or the other (see above). The benefit of a bifold door is that when the doors are all open stacked to the side, you have only a small part of the opening used because the door faces are stacked against each other. You need a strong header in the opening to install the bifolding door system to, or the doors will not fold smoothly.

If there is a downside to a bifold door system, it is that the doors fold to the exterior, so the bundle of folded doors will stick outward onto the patio as much as 36.” Bifold door panels can’t be too wide because they hang from the head jamb, so they require a larger number of doors to bridge an opening, and when closed, the door panels sit side by side (edge to edge), which makes for less daylight than in a sliding door system.

Bifold Design Tip: When planning your bifold door system, be ODD! That’s right, an odd number of doors folding in one direction gives you a Daily Door on one side. Just heading out to the barbecue? The daily door can fold with the rest of the doors, and also serves as a single swinging french door when you don’t want to fold open the entire unit. So think 3,5 or 7 doors for the most user-friendly door system.

Lift and Slide Patio Doors

Lift and slide patio doors are a more massive version of the typical sliding patio door system you may be familiar with. European hardware makes it easy to smoothly slide doors that are extremely wide and thick so you can open up entire walls with the turn of a handle. The doors slide on a staggered track system and “telescope” (pull the door behind it along as   When fully open, lift and slide doors stack directly behind one behind the other, and when closed their stiles (vertical members of the door that block the view) overlap so you have more daylight per door than with a Bi-Folding system.

The downside to sliding patio door systems is that there is always a door or doors covering up part of the opening, even when all the doors are in the fully open position. Another consideration is that each lift and slide door is 2-1/4″ thick, so in order to slide more than a few doors in any direction, you will need a fairly thick wall to accept the sliding door jamb. This wide wall can be easily planned into a new home, but if you are remodeling your existing home, you might have to do some reframing of the wall where the lift and slide is going to go.

Pocketing Lift and Slide Patio Doors

The best possible way to live the indoor/outdoor lifestyle is to have your builder construct a “pocket” in the wall that all of the doors can slide into and hide whenever you want the wall open. Pocketing sliding doors can be ordered with either removable handles or folding handles, so the doors can slide all the way into the pocket and disappear. When you want to close off the opening again, a retractable pull in the leading edge of the first door can be popped out and used to begin sliding the doors out of the pocket.

So, bifold or lift and slide? We’d like to hear how you will expand your world view!