I realized our 35-year-old wobbly wooden grape arbor would not survive another year when I noticed two of its six cedar posts completely rotted off inside their metal support brackets. The tree-side posts seemed to stand higher than the rest of the posts. The brackets themselves were also well rusted.
Note the lower 1/4-inch bolt is almost rusted through in the metal post bracket shown.
The concrete beneath the arbor had cracked and been lifted by tree roots. In any struggle between concrete and tree roots─the roots win.
A portion of our backyard concrete sport court was being repaired/replaced (due to a fallen tree) at this time, so I had our contractor jack-hammer the busted arbor concrete floor and remove it as well.
I don't know which idea came first, a new shady area crushed rock pathway or replacing the arbor floor. I knew that crushed rock for the arbor floor would allow for tree root movement and stay in place.
While considering the rebuilding process, I concluded the old arbor wasn't too practical. It was only six-and-a-half feet tall and made me feel claustrophobic when I stood inside it. It's footprint was also small (just under eight feet wide and eleven feet long), barely enough to accommodate a picnic table. With the low "ceiling" I always had the impression spiders could easily drop onto my head.
I'd read that garden structures (patios, decks, pergolas, etc.) should be generous-sized because our vision of our outdoor space includes neighboring trees and sky.
My advice: BEFORE you build (or buy) something, go outside and visualize your project twice the size you drew on paper and you'll see what I mean. If you buy at the garden centers, take a picture of the item first with someone standing beside it for 'human' scale and then take the photo home and visualize that item on your property. Way too much stuff sold in the garden centers looks tiny (out-of-proportion) when placed in your landscape back home. (In my humble opinion, of course.)
The old arbor posts were cedar 4 by 4's and the horizontal cross beams that tied to the posts were cedar 2 by 4's with cedar 2 by 2's nailed onto the cross beams to support the grapevine. Nearly half of the top 2 by 2's were cracked or broken due to falling limbs over the years. Each of the six posts was crossbraced in two directions with 2 by 4's which somewhat restricted access to and from the arbor. Seven-foot integral benches were fastened between the end posts, which further restricted entry.
Sketch of the old arbor.
I decided that the original 4 by 4 posts looked too skimpy, and six of them were too many. I opted for four 4 by 6 posts and drew a to-scale sketch to determine pleasing proportions. I opted for a pair of 2- by 10-inch by 16-foot-long main beams, which allowed some overhang on each end.
The grape vine was very old and heavy (and the thick trunk appeared brittle), so I left the old arbor temporarily in place. I increased the overall footprint and placed four cardboard tubes (to hold new concrete footings and new post brackets) in their proper places. I was careful to level the tubes to each other using a long 2 by 4 and my level. After the concrete was in the tubes, I carefully set the new metal bracket post supports in the wet mix and tapered the top of each concrete footing to drain off water.
Once the concrete had cured a couple of weeks I placed the four posts and braced them as I would fence posts (I tacked a 1 by 4 to each post and to a nearby stake in two directions after checking for plumb in each direction).
Getting those long heavy 2 by 10's into place required the assistance of my daughter and a stepladder. I tacked a temporary chunk of wood near the top of each post to support the beam from below until I could get a couple huge nails pounded into each end to secure them to the posts. Before raising those beams I fancied up the ends. I started the two cuts with a portable circular saw and finished them with a handsaw.
The "fancy" end required two cuts: one from the bottom and one angled in from the end. Simple, yet effective and decorative.
To tie all the posts together, I cut two 2- by 10-inch cross-beams to fit between the long beams and nailed them to the posts on both ends. I considered adding another crossbeam in the middle (supported by joist hangars), but decided it wasn't necessary.
For wind stability, I cut a pair of 4 by 4 by 8's into eight pieces with 45 degree ends. I will refer to these as the 'angled wood supports'. See cutting pattern below.
If you decide to cut something similar, it helps if you have a 10" or larger chopsaw because these cuts can take a REALLY long time if you're doing it with a hand saw. Home Depot sells a utilitarian Ryobi 10" model for $99.
My 10" Ryobi chopsaw. Very handy for outdoor projects. Lightweight, strong, easy-to-operate (and cheap).
A table saw or a radial arm saw works for this too, but handling 4 by 4 by 8's on a table saw can be challenging. (Should I should write an article about the tools I use when building garden structures some day?)
The dashed lines depict the 4 by 4 cutting pattern. Cutting the wood angled supports goes much faster with a 10" powered chopsaw set at a 45 degree angle.
I mounted the angled wood supports to the posts with 5-inch long 1/2-inch diameter lag screws into pre-drilled and pre-countersunk (at an angle) holes in the brackets.
TOOL TIP: If you're using a hand brace with a lead-in-screw tip on the end of the drillbit, drill the countersink FIRST, otherwise there's nothing for the lead-in screw to grab into except "air".
TOOL TIP: The countersink bit size (diameter) is determined by the outside diameter of the lag bolt washer you use.
My hand brace and countersinking drill bit with lead-in screw tip (shown on left).
I needed a helper (again) to hold the angled wood supports in place while I fastened the lag bolts with a socket wrench.
Note the angled countersink where the bolt attaches to the wooden angled support.
A pair of lag screws (with washers) were attached through the outside of each corresponding beam and into the upper portion of each angled wood support.
Two lag bolts hold the upper end of the wood angled support to the long beam. (If you look closely, you'll see my oopsie, two extra holes drilled to the right of the existing lag screws. Well...I never said I was perfect.)
I placed a couple of 2 by 4's on top and gently eased the vine up to its new location. Then I slipped additional 2 by 4's into place along the long beam while a helper continued lifting the vine (for clearance) with the aid of a long stick.
This is the arbor today. Picture was taken in early spring, the grapevine is just beginning to leaf out and Cookie, our dog, is standing in the rain. She is part Yellow Lab, but definitely not a "water dog", so go figure.
The finished arbor has been in place about a year and I expect it to last at least 30 years. I used pressure-treated lumber and galvanized hardware throughout. The bottoms of the posts should drain freely in the crushed rock.
The arbor is shown with the grapevine in full bloom last summer. That's a cherry tree in the right foreground.
I'm guestimating our rebuilt arbor cost about $500, including forms, hardware and lumber. I bought my materials during the recent housing boom. Perhaps one could build one for less today. If you do, DON'T skimp on the quality of your materials. There's a lot of labor in this project, so you'd want it to last a LONG time.
I cut up the old cedar arbor into small pieces and split it. It had never been treated or painted, so it provided lots of kindling for the firepit.