How to Build Deck Attached to a Bay Wall

Building a deck can be straightforward when the wall it is attached to is straight. What do you do if you want to attach the deck a bay shaped wall? Here's how to build a deck attached to a bay wall.

Difficulty: Moderately Challenging

Instructions

Things You'll Need:

• Paper (Graph Paper Preferred)
• Ruler
• Pencil
• Deck Design Software (optional)

1. Get proper approvals to build the deck with your local government and in some cases, the home owner's association.

2. Be familiar with the local codes for designing your deck.

3. Plan the deck on paper or in a software program. The quickest and easiest way to plan is making a rough sketch on paper. You can transfer the plan to the deck designer software for a more detailed plan later.

4. 
    

   Design the deck as if there is no bay wall protrusion. The figure shows a frame (orange outline) of a rectangular shaped deck. This will allow you to plan where you want to put the ledger.

5. 
    

   Draw the ledger in the plan. It is in red in this figure. Draw where you want the joists to attach onto the ledger.

6. 
    

   Examine where the joist is going to attach to the bay wall. If it looks like it will land on a corner, adjust the plan so that the joists lands at least 3 inches away from the corners. This space will allow room to nail the joist hanger on the ledger. In this example, there are 4 joists that are close to the corners.

7. 
    

   If the joist will be too close to the corners, move the position of the joist. The spacing of all the joists need not be evenly spaced.

8. 
    

   Draw the ledger around the bay wall. It is red in the figure. Redraw the length of the joist (blue in this figure) so that the joist attached to the ledger.

9. Using your own deck plan, determine the amount of wood you'll need for the frame, joists, and standard joist hangers. Also decide the amount of angled joist hangers you'll need. In this example plan, only one 45 degree joist hanger skewed or angled to the right and one 45 degree joist hanger skewed to the left would be needed.

10. Start the deck building by installing a ledger to the house. In this example, the ledger will cover the perimeter of the bay wall and straight wall.

11. Build the deck per plan. For the joists at the angled walls, use angled joist hangers. There are 45 degree left and right hangers and there are hangers where you can change the angle.

12. Ensure that the joist hanger doesn't end up on a corner when you test fit the location of the joist. Sometimes the plan on paper can deviate when you do the actual work.

13. When completed, pat yourself on the back. This type of deck is more challenging to build.