Build A Porch Video Part 2 of 6
The first issue deals with the original builder placing the Trex decking right up against the house and then installed the siding right down on top of the decking. This caused the fiber-cement siding to rot. Because the house is located in a cold climate, water was being soaked up into the underside of the fiber-cement siding and freezing, expanding and falling apart. It got so bad that the siding is just flaking apart.
Here's a big problem. The builder an carpenters thought they were going to do a good job by putting on the flashing on top of the band board. The band board is nailed directly to the sill plate, that is on top of the foundation. Since they didn't want to get water behind the band board, they installed a piece of aluminum for the flashing. But they goofed-up.
The flashing is a piece of tin with a 90-degree up bend on one side and a 90-degree down bend on the opposite side. The down bend should have a slight outward curve to it. The tin-flashing should have been placed on top of the band board. The upturned part of the flashing would go well up behind the siding. Maybe 3" or 4".
When the porch was build, they ended the flashing even with the edge of the band board. There was no down-turned part. The correct flashing should go over the edge of the band board and end with a little kick-out bend. This kick-out allows the water to form into a drop and drip down away from the band board. Without the kick-out, when the water forms the droplet, it runs back underneath the siding due to capillary action. Bad idea!
Finally where they lapped the pieces of aluminum, they just did a lap joint. There is no sealant or caulk. (I don't like caulk. I prefer tin flashing so all the seems can be soldered.)
One more problem is the floor joists are just toenailed into the band board. They should have used structural joint hangers. That was a big mistake.
To correct this problem, we will completely disconnect the framing from the house. We will make the siding go down over the foundation. The deck will be supported off the foundation using structural steel angle iron that will be bolted to the foundation. That is coming up in the next video.