This weekend I will complete the refurbishing of my 20 year old pergola. I find it is useful to take a second look at a project and see how you could have improved the design. Here’s what I learned from the pergola:
1. I failed to appreciate that once the stephanotis vine took over the pergola that I would be unable to maintain the finish. You know when wood sits in water it will rot and it did.
2. I should have primed and painted all of the limbers before adding the top cross pieces. I assumed that because I used blocks between all of my 2×2 cross pieces that the underlying limbers would be protected-not true. What I discovered was that the water worked its way down the shaft of the nail and compromised the wood underneath and that realization surprised me.
On the positive side, the posts and underlying structural limbers were protected by the awesome Simpson ties that I used. My 2×4 cross bracing keep the structure true and solid.
I ripped off all the 2×2’s and used epoxy to repair any damage to the limbers directly below those pieces. I then primed and added two coats of paint to the repaired limbers and all of my crosspieces. This time I have added aluminum flashing with a small drip edge on all the cross pieces and any horizontal piece below to prevent future water damage. I used this technique on my fence and it works great. If you think, about isn’t the top of a fence or a pergola similar to a small roof?
-- cathyb, Hawaii, www.cathyswoodworking.com