A: Door sweeps are designed to block drafts from coming in through the gap between the bottom edge of a door and the threshold. They are attached to one side of the door, close to the bottom edge, and have a flexible material that hangs down and plugs the gap. Some sweeps have bristles that resemble brooms, thus the term “sweeps,” while others have rubber-type flaps, usually vinyl.
Whatever the style, it’s important to recognize where the seal needs to take place. If a door swings in, as most residential front doors do, the sweep is on the inside and seals against the part of the threshold that is directly under the interior edge of the door when the door is closed. Only when an exterior door swings out does a sweep go on the outside. The threshold design, with a lip and a slope toward the exterior, is what stops water from getting in.
But based on how you feel multiple bands of rubber under your door, you don’t have door sweeps. Instead, you have shoes, which are sometimes called caps. These are U-shaped assemblies with arms that wrap around the bottom edge of a door. The bottom of the U holds flexible material, typically vinyl, that’s not within view. This is what seals against the threshold. Shoes create a tidy look and protect the bottom edge of wooden doors from becoming wet. But they can be more complicated to install and adjust. To fit in the shoe, the installer needs to take the door down from its hinges unless there is enough space to slide in the shoe while the door is open.
The handyperson probably installed a different brand of door shoe than was originally installed on your doors, resulting in a different height of the U-shaped arms. That’s a visual detail only. The functional issue is whether the shoe was installed so it seals against the threshold. One way to test that is to close the door over a sheet of paper or a playing card and to see whether it falls out. If so, the gap is too big. You should feel slight resistance as you pull it out. If you have to really tug, the fit is too tight for easy operation of the door.
Because you describe your threshold as metal with a narrow band of wood or plastic on top, you probably have the type that makes it easy to adjust the gap between a shoe and the threshold: Turn the screws holding the strip at the top, and it will move slightly up or down.
Double exterior doors that swing in are notoriously difficult to weather-seal, because wind and rain push against the doors in the same direction as they are made to open. If you see water seeping in at the bottom of the doors, check whether it is coming in below the threshold. That could mean sealant wasn’t applied properly when the threshold was installed. To fix that, you’ll need to cut the threshold in the middle, so you can pull it out, sideways, in two sections. Then replace the threshold. The type that has metal on the outside but a wood insert on the interior and a wood top piece, which it seems as if you have, is better than an all-metal threshold, which gets so cold that condensation — and eventually mold — will probably form on the interior surface during winter.
If the water is coming in over the threshold and the shoe is adjusted properly, a different type of shoe might solve your problem. Get one with an extra feature that directs water away from the door, such as M-D Building Products’ 36-inch U-shaped door bottom with a drip cap, $12.94 on Amazon.
It might also help to improve the way the door that’s usually left closed is pinned in place. If it’s not secure, the door that’s usually opened doesn’t stay securely closed, either. If the inactive door isn’t latched at the top and bottom, install bolt-type latches made for this purpose. If your door already has these, you might need to adjust the strike plates where the bolts fit. The best solution is a multipoint locking system, which has deadbolts at the top, middle and bottom, but that would probably mean buying new doors, because adding it as a retrofit would be tricky, because the locking mechanism needs to fit into a precisely routed channel in the door edge.
If the water is coming in over the threshold, adjust the fit against the shoe. If the problem persists, even when the shoe is adjusted correctly, you might want to consider adding a porch roof or awning overhead to shelter the entry. But that’s an expensive proposition that, with luck, you won’t need.