One of the most vulnerable spots on your exterior door is one that you generally don’t think about until there is a problem. Whether the door is wood, fiberglass or aluminum clad there is usually at least some wood in it’s frame work.
Rain water can soak in through the unsealed bottom of the door. This will cause the door to swell in the opening and get stuck when you try to open or close it. Water soaking into and remaining in the door will cause damage, mould and rot over time. Because of these problems it is very important to seal the bottoms of your exterior doors at the time of installation. Unfortunately, it is a part of the job that often gets overlooked until there is something wrong.
As part of the quality door installation service that I offer here in San Luis Obispo County I seal the bottoms of all exterior doors that I install. I use a waterproof glue tinted with brown paint pigment to seal the bottoms of all of my exterior doors. The glue, because it is glue, bonds better to the door and seals better than a quick coat of lacquer or primer that usually gets applied.
I brush it on liberally with a disposable brush. The edges of the doors absorb the most water at the bottom because the edges of the door have end grain at the top and bottom It’s the same way the tree absorbed water before we made it into a door. It sucks up water like a bunch of soda straws. Because of this characteristic I apply a second coat of sealer to these areas. I dry the first coat with a heat gun and then apply a second coat to the end grain areas and any other parts that look a little thin.
After the glue sealer has dried I install the door for the last time and complete the installation by installing weatherstripping and door shoes.
Be sure to seal the bottoms of your exterior door. If it is an outswing door, follow the same procedure on the top of the door. The tops of inswing doors are not as critical and can be sealed as part of the staining or painting process.
Finally it is important to remember that sealing all of the edges of your exterior door is a requirement of most door manufacturer’s warranties…Remember to do it!!