Simpson® Performance Series® doors include components that provide additional protection to your door in harsh weather conditions.
![Simpson Performance Series Doors.](https://s3.amazonaws.com/cdn04.prod.aws.learn.reeb.com/assets/articles/simpson-performance-doors/simpson-performance-patio-doors.jpg)
Performance Series doors utilize three moisture blocking features. First, they utilize UltraBlock® Technology
which is a 4" water-resistant composite block added to the bottom of both door stiles.
![Simpson UltraBlock Construction.](https://s3.amazonaws.com/cdn04.prod.aws.learn.reeb.com/assets/articles/simpson-performance-doors/ultrablock-construction-detail.jpg)
Second, they feature the Weather Seal process where glue is applied along the entire coped area of the stile blocking water absorbtion and enhancing the glue joints.
![Glue being applied to door stile.](https://s3.amazonaws.com/cdn04.prod.aws.learn.reeb.com/assets/articles/simpson-performance-doors/door-stile-glue-application.jpg)
Finally, all Simpson Performance Doors stocked by Reeb come with a solid bottom rail. Solid lumber is very durable especially in this vulnerable area of the door.
By incorporating all three of these into a door, the entire bottom of the door is protected against moisture penetration.
![Simpson Performance Series door on front of home.](https://s3.amazonaws.com/cdn04.prod.aws.learn.reeb.com/assets/articles/simpson-performance-doors/simspon-performance-series-door.jpg)
Included as part of the Performance Series® doors is the WaterBarrier® Series.
WaterBarrier doors combine a Medium Density Overlay (MDO) with water-resistant glazing beads and bars
to create an exterior that stops water in its tracks.
![Medium Density Overlay Construction.](https://s3.amazonaws.com/cdn04.prod.aws.learn.reeb.com/assets/articles/simpson-performance-doors/mdo-overlay-detail.jpg)
WaterBarrier technology can be used on virtually any species to receive the highest protection on the exterior of the door
while getting the unmatched beauty of a real wood door on the inside.
![Exterior Double Door Unit with Simpson WaterBarrier Technology.](https://s3.amazonaws.com/cdn04.prod.aws.learn.reeb.com/assets/articles/simpson-performance-doors/performance-series-double-door-unit.jpg)
![Real Wood Interior Side of WaterBarrier Technology.](https://s3.amazonaws.com/cdn04.prod.aws.learn.reeb.com/assets/articles/simpson-performance-doors/water-barrier-real-wood-interior.jpg)
The Performance Series® takes an amazing wood door crafted with impeccable details and gives it an additional layer of security.
Doors with both Performance features and WaterBarrier® technology create a door suited for the toughest exposures.
Beauty is important in any door, but a beautiful door is only worth having if it lasts.
![Simspon Performance Series Door with Sidelites.](https://s3.amazonaws.com/cdn04.prod.aws.learn.reeb.com/assets/articles/simpson-performance-doors/simpson-performance-series-door-with-sidelites.jpg)