It's a common misconception that exterior siding is waterproof. No matter what type of siding you have on your home, eventually, moisture can make its way through. That's one reason brick masons install weep holes, stucco contractors use weep screed, and vinyl siding has drain holes in the bottom of each piece--to help the moisture that gets in, get back out again.
Your exterior siding is a moisture deterrent, but the material behind the siding is the final guard against water entering your home. That's why you must:
- Install your exterior sheathing correctly
- Repair any damage
- Make sure your house wrap is secured according to the manufacturer's recommendations
- Check and repair flashing prior to starting your DIY siding project
Where to Check for Flashing During Your DIY Siding Project
Builders usually use flashing in combination with the flange or designed drainage system of items which penetrate your exterior siding. Some of the items on the outside of your home that should be flashed are:
- Doors
- Windows
- Exterior vents
- Exterior trim
Builders normally install your exterior siding up to these areas, and even install a trim piece, such as vinyl siding's J Channel. But, this doesn't always prevent moisture intrusion, especially on a horizontal surface where water can puddle. All top surfaces of these penetrations should have aluminum flashing. In fact, some window and door manufacturers recommend a combination of aluminum and rubber membrane flashing.
Aluminum flashing is available in white, brown, and black coil stock. Some manufactures offer colors. Double check and repair your flashing prior to starting your DIY siding project. Doing so may save you from expensive water damage repairs in the future.
