How to flash a ledger for a pergola?

Question

Hi, I'm building a pergola that will be attached to the house. The house is brick up until about 10 feet, then its vinyl siding up to the roof. The ledger (2 x 8 x 12 feet) is going to be fastened to the house where the brick meets the siding, so that the board is surrounded by the siding on 3 sides and brick on the bottom side. I plan on cutting away the vinyl siding and using countersunk lag bolts to secure the board to the studs behind the siding.

So my question is--how do I flash the ledger and make sure I can waterproof this thing?

1. Should I squirt some silicone right into the pre-drilled holes in the studs for the lag bolts?

2. Should I leave a gap (with washers) between the ledger and the house?

3. When I flash the ledger, how much of the flashing do I bend over the top of the ledger--does it need wrap all the way over board, like in a Z-pattern (which I think will look ugly) or can I just get away with a 90°, like an L-pattern? And how to I attach it--nails?

And finally,

4. Do I need to use J-channel and how the heck do I use it?

Answer 1

They make a rubberized flashing that is backed with tar for windows. I would take this and flash between the board and the j-channel. The idea is to funnel the water away from areas you do not want it. So take down siding.(Will probably have to remove the piece above and to the sides as well. There is probably a j-channel sitting on the brick. This you will want to move as well. Place your board up there and trace the outside edge. Your rubber window flasing will sit half on one side of line the other on the other side. I would then bend a piece of alum. trim that will fit behind your ledger come across your brick and barley hang over the face of the brick.  This is installed with small panel nails or trim nails. Put your first piece of rubber flashing over edge of the alum. trim placing it horizontal or length ways. Continue moving up, over lapping the next at least 2" and will probably want it 8" extra long on each end to go under the siding.  Do this until you go over your line you drew. Put board up with lag bolts against wall. Take j-channel and outline your board with it.  In the corners if you experiment with cutting you will see that you can turn a corner and have overlaps that will still contain the water. Reinstall siding and make sure it moves freely.  Water coming down the siding will enter the j-channel and be swept away.  Small cracks between your ledger and J will be waterproof with the flashing behind it.  If it gets back there then it can exit at the bottom over the alumin. drip edge. Go to VSI webpage and order an installation manual.  Think it is 5 bucks.  Will not help with the ledger but will help with cutting the j, flashing techniques, bending techniques, and siding installation.  May be an easier way but I think this will keep you in the dry...Hope it helps.