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Gap/air leak at prehung door at jamb directly above sill

user-5946022 | Posted in General Questions on

Has anyone used a door sealing product named “Corner Seal Pads” or “Door corner seals” made specifically for sealing the gap between the door and the jamb weather stripping, directly above the sill? 
– If so, do they work?  
– Is one type better than another?  They seem to come in compressible foam similar to door weather stripping, as well as a neoprene type material.

My pre-hung doors to the exterior (in a relatively new house) have very thin, 2-3″ long gaps between the door and the jamb weather stripping, starting directly above the sill.  I can see a slight bit of light.  It appears that the rubber drip edge/sill seal that goes across the bottom of the door at the exterior pushes the jamb weather seal toward the stop, and compresses it just enough to create a slight gap.

I selected fiberglass doors, because I thought they were less susceptible to warping than wood or metal.  My builder also dismissed the idea of multi point locks as overkill, so I have ThermaTru prehung fiberglass doors with standard latches/locks.  Googling Therma Tru doors indicates that perhaps my doors came with these corner pads and they were just never installed.

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  1. DC_Contrarian_ | | #1

    Doors are typically sold as slabs to a distributor, who hangs them in a frame and installs weatherstripping. So Therma-Tru doesn't control how a Therma-Tru door is finished.

    In my experience anything that is glued or otherwise stuck onto a door will come off in time. The only thing that really works is weatherstripping put into a kerf cut into the door frame.

    If one piece of weatherstripping is pushing aside another, can it be trimmed? Also, kerf-style weatherstripping comes in sizes, when there's a gap I've had good results replacing it with one size bigger.

  2. Expert Member
    Michael Maines | | #2

    I don't think I have ever seen those pads installed on a new door, Therma-Tru or otherwise. On a few occasions they have come as a loose item to be installed on site, and on other occasions I've requested them from the supplier and installed them myself. They do a decent job of sealing those gaps, but they often (perhaps always) end up falling off or getting crushed.

    It's a problem, but if you only have one or a few exterior doors, it's not a huge problem--more like a minor annoyance. If you want better performance, look into doors sold by window manufacturers, including but not limited to European-style window and door manufacturers.

    In the words of the Green Architects' Lounge guys, a six-digit idea would be to come up with a product or redesign that solves this problem.

    1. user-5946022 | | #3

      Thank Michael. Given your statement that they do a decent job, I fashioned a "corner seal" myself out of some fairly thin neoprene with peel & stick on one side, that was leftover from some other (now unknown) item installed on this house. I cut the neoprene pad to a shape similar to the shape shown on the ThermaTru site, and installed it similarly.

      My reason for wanting to seal the gap is both performance and to keep out bugs. If I can see daylight through the gap, bugs can come in. This DIY corner seal has indeed closed the gap through which I could previously see daylight. The solution seems simple enough that I'm going to install it on both sides of the jamb on all exterior doors. We shall see how long they stay put.

      Although I very much want better performance, I'm not in a position to replace the doors in a new home I've lived in for less than a year!

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