What is the best way to seal the gap in a door without replacing it with drywall – foam insulation backer rod or canned insulation?
Asked by Amir Byrkjeland 
3 weeks ago
Last Updated: October 30, 2024
A: Hey, B, what should I put in the gap by the door? I don’t want to use drywall. Do you think foam insulation or backer rod would work, and then we can put the trim back on?
B: Canned insulation was used for sealing before. Should we reapply it or try a different approach before putting the trim back?
Wow, what a disaster! Any idea why the carpenter who installed this left a gap instead of centering the door in the rough opening? Could it be that the door is too small or the opening is too large? Let’s move forward…simply cut filler blocks around six inches long and place them at the top, bottom, and hinge locations, spacing them at least 12 inches apart. Make them thinner so that door shims can be inserted to ensure the proper fit and keep the frame straight and plumb. Then, put the trim back on. You may need to shift the entire door to the center of the rough opening if the trim can’t cover the gap. It will require more effort, but it’s the right thing to do.
Had similar thoughts to what you mentioned, thank you.
Pointed out that the dark area in photo A is actually the door casing, not a space between the frame and the stud.
Do you have any pictures from a distance so we can get a better idea of what you’re dealing with? It’s a bit hard to tell from the close-up photos.
Managed to turn it around, haha
The door has an added frame over the door jamb and some parts of it are missing
When setting up interior door frames, there’s always a gap left for shims to ensure the frame is square and plumb within the rough opening.
Currently I have some backer rod squished in it, considering lightly foaming it as well
It will be concealed behind the trim to prevent drafts and insects
If it’s an interior door, it’s fine to leave a gap and then trim it out. It’s a bit hard to understand the full situation from your photos. Maybe try posting some shots from further away for a better perspective.
Seems normal like others mentioned. For the exterior door, use foam to fill the gap and then trim it. For the interior door, just finish the trim to cover that small gap. It would be helpful to have clearer pictures.
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For exterior doors, I use window and door spray foam to fill in the gaps, trimming off any excess once it’s fully cured.