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Fill for underneath exterior door threshold?

OregonBob's Avatar

Join Date: Dec 2016
Posts: 1

12-01-16, 03:10 PM   #1  
Fill for underneath exterior door threshold?

Put in a new exterior door that fits really well and sits very well on the concrete perimeter foundation. On the outside portion of the door, the threshold sits in the corner of a concrete patio that slopes away from the house. Because of this, the downhill side has about 1/4"-3/8" gap. Every time I step on that corner of the threshold, it sags. I'd like to fill underneath this corner with something more solid that caulk. Any suggestions?

Thanks in advance!

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ray2047's Avatar
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12-01-16, 04:08 PM   #2  
I would try mortar. .

I can explain it to you, but I can't understand it for you.

XSleeper's Avatar
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12-01-16, 04:15 PM   #3  
I hope the door is sitting in a heavy bead of sealant to seal the bottom from water intrusion. If the gap is 3/8" or less, I would use pairs of tapered composite shims every 8" or so... then use a polyurethane sealant... either OSI Quad Max, or maybe Loctite S10.

What color is the sill? Mill aluminum? Brown?

joecaption's Avatar

Join Date: Jan 2011
Posts: 3,963

12-01-16, 04:24 PM   #4  
Post a picture so we can see what your seeing.
Looking to see if there's room for the needed support against the outside wall that sits up under the overhang of the threshold.
Also know as a kickboard.

Handyone's Avatar
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12-01-16, 04:26 PM   #5  
I would tape off the area and fill the gap using a grout bag.
I redid the stucco on my house and this solution worked well to support the threshold before finishing the exterior.
X is the man though for doors.

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