We've been on a tear here lately at the Chez getting things buttoned up for the winter. One of the things we needed to tackle was our back door. There was an 1.5" gap between the bottom of the door and the rotted out old wood threshold and when it was cold outside an icy wind would blow through this gap. Since this door is right next to the babies room with only a heavy curtain separating it, it was a high priority to get this huge source of cold air sealed up before it got really cold.
Here's the old wooden threshold and the bizarre gap in the floorboards it was spanning. This gap was full of old leaves, rat poop, and decomposing somethings or another. I got all the gunk out and vacuumed it and the wood underneath was in great condition. Yay for old growth redwood.
If you notice in the top pic at the bottom of the door a door sweep was installed with about 100 screws...Unfortunately it was installed so incorrectly that it trapped water between it and the door. It hadn't rained for weeks but when I removed it, the bottom of the door was soaking wet and spongy! Not good...plus check out the failing paint.
Since the slope was correct I used some leftover flashing tape to form a sill pan. If any water gets under the new threshold it should drain out the bottom without soaking into the framing and ruining it. The flashing tape is tucked up under the door trim on either side also.
Because of how wide the gap was and how wide my sill pan was I had to improvise a bit. I installed the new aluminum threshold in its proper place and then I used a leftover 5/4" by 6" piece of Ipe to cover the rest of the sill pan. I kerfed the bottom of the Ipe with my SCMS so that any water that runs down the door and down the aluminum threshold will still drain out between the Ipe and the flashing tape sill pan. After this pic was taken I trimmed the flashing tape flush with the Ipe.
Next up we need to work on fixing up the door to make it through the winter rainy season.