External door non-standard sizes

When replacing an external door with a non-standard size is it advisable to do the whole frame with a pre-hung replacement? Observing external door slab to be replaced is 79" by 31 3/4" by 1 3/4". The door is roughly 25 years old. Seeing many websites appear to list out of stock in this size, but appears non standard today. It would be lovely if an external door of the same size could be acquired and dropped into the existing frame. From experience with swapping hardware out on inside doors I have intuition that it's not going to be so simple and that replacing the whole frame with a prehung door may take more work but have potential to be less work overall if purchasing door slab alone doesn't work out without issues. Insight from the experiences of those that work with this sort of thing more often would be helpful. If issues are less risk than I'm imagining for replacing door slab alone I'd go that route. Skip beyond this point if details aren't material. Replacing a 25 year old metal external door due to rust and mold. Observing flakes of rust at the base and see that the weather stripping forms a U shape that traps moisture in the bottom of the door. Over time this has rusted to the point that the metal at the bottom is compromised and flaking out with each open and close of the door. Additionally observe mold that appears below the layer of paint of the door. Prior owners layed black mulch around the planters for curb appeal when listing the property and have learned this is a major source of introducing mold to surrounding surfaces. Stripped this out and replaced with gravel. However, observing signs of mold below paint on the door and frame surfaces that does not remove when power washed. Seeing this as indication there may have potentially been mold issues with the door and the frame in the past painted over when the house was readied for market. It's also possible a skill issue and I do not understand the nature of mold and its ability to work into paint on finished surfaces haha. Based on these two factors replacing the door makes sense. And seeing the sizing does not match majority of the standard sizes available at local brick and mortar outlets. submitted by /u/decrementsf [link] [comments]

Mar 24, 2025 - 17:36

When replacing an external door with a non-standard size is it advisable to do the whole frame with a pre-hung replacement?

Observing external door slab to be replaced is 79" by 31 3/4" by 1 3/4". The door is roughly 25 years old. Seeing many websites appear to list out of stock in this size, but appears non standard today.

It would be lovely if an external door of the same size could be acquired and dropped into the existing frame. From experience with swapping hardware out on inside doors I have intuition that it's not going to be so simple and that replacing the whole frame with a prehung door may take more work but have potential to be less work overall if purchasing door slab alone doesn't work out without issues.

Insight from the experiences of those that work with this sort of thing more often would be helpful. If issues are less risk than I'm imagining for replacing door slab alone I'd go that route.

Skip beyond this point if details aren't material.

Replacing a 25 year old metal external door due to rust and mold.

Observing flakes of rust at the base and see that the weather stripping forms a U shape that traps moisture in the bottom of the door. Over time this has rusted to the point that the metal at the bottom is compromised and flaking out with each open and close of the door.
Additionally observe mold that appears below the layer of paint of the door. Prior owners layed black mulch around the planters for curb appeal when listing the property and have learned this is a major source of introducing mold to surrounding surfaces. Stripped this out and replaced with gravel. However, observing signs of mold below paint on the door and frame surfaces that does not remove when power washed. Seeing this as indication there may have potentially been mold issues with the door and the frame in the past painted over when the house was readied for market. It's also possible a skill issue and I do not understand the nature of mold and its ability to work into paint on finished surfaces haha.

Based on these two factors replacing the door makes sense. And seeing the sizing does not match majority of the standard sizes available at local brick and mortar outlets.

submitted by /u/decrementsf
[link] [comments]