Now we are going to show you how you can attach a new picket fence to a pre-existing picket fence. Now what we have done here is we have taken this pressure treated 2x4 and we have simply nailed it to a pre-existing 2x4 foot pressure treated frame. Now within a 2 inch span here there is another 4x4 foot post. Now if this was a load bearing fence, a taller fence, a heavier fence, a fence that we needed to have security with, then I might have thought about dropping in another 4x4 foot post. Again since there was one very close to this new fence I didn't feel as if this frame was going to go anywhere. Any time you attach your fence to an existing wall or home you have to contend with the footing. So what you can do here, what we have done here is we took our 4x4 inch posts, a good ten inches from the house, just missing the footing. We took our 2x4 foot frame within an inch of the house. We squared off our pickets and by using our plumb line we are ready now to install the rest of our pickets.