I have an existing fence, about 6' high, of pressure treated 4x4 posts, on 8 foot centers, holding up thin 1/2" cedar boards, on 2x4" PT wood. Very common setup.I have been in the process of raising the ground in my yard, through a series of retaining walls, to the level of a parking lot, which is directly behind this fence. So the overall goal is to eliminate the view to this obnoxious lot, by raising the fence a total of 8-10 feet in height. *Note: the ground in the parking lot is about 4' higher at the highest point, above the ground in the bottom part of my yard. So as people get into their vehicles in the morning, they can see me in my underwear eating breakfast and drinking coffee, since I work from home.Before you go on about city building codes, I have thought this through already. The fence won't be higher than 6.5' ish from BOTH sides of the fence. A little high, but who's complaining? I will add another 2 foot of wire to the top to support, a viney plant, which will bring the overall visual screen to a height of 12 feet from the bottom of my first floor and backyard.To make a long story short, I have manually moved about 40 yards of earth, and have bult the "Great Wall of Humaniteer" (as my wife calls it), and I am in a phase of building which will now allow me to attach another set of 4x4" PT lumber to the existing fence structure. This 4" space, which runs the length of the fence, between the fence posts, will be embedded in 2' of concrete, with rebar. On one side of my concrete pour is a flat wall of cheap pre-molded concrete patio stone, which I have vertically stood up. On the other is a sandwiched layer of cedar fence board, then 3/4" plywood, and backfilled with broken concrete, rocks, and earth. This wood will decay over time, by design. So, I am laying cheap scrap metal into the ditch, as reinforcement, and plan on filling this ditch with concrete, tying the patio stone wall and posts together. This should get my post tops to the desired height of around 10 feet over the bottom level of my yard, while maintaining a strong foundation for a tall fence in high wind areas.I have looked at using metal poles, but they are $$$, as opposed to the PT which is just $$. The top length will be 1 3/8" metal fence toprail, or 3/4" electrical conduit, which will support a reed mat. I will be hanging the reed mat as a screen from the parking lot, so it is very light, but we also get heavy winds in my area. So I decided to hang the wind screen from a top rail metal fence pole (or the conduit), so that it can "pivot" in a high gust of wind. I figured this would drastically lessen the horizontal load on the vertical PT posts.So my question is will this type of fence/screen system work in an area which gets heavy gusts of wind? Will electrical conduit be strong enough to not bend in the middle during gusts (reed mats weigh approximately 20 lbs/15' section, and I am weaving in another 20 pounds/15' section of material into the mat)? What type of fasteners would be most corrosion resistant? Will a zinc fastener embedded in a copper compound treated PT post degrade over time? I was looking for a 2 1/2" lag bolt, zinc hot dip galvanized grade 5 steel, to put into a copper fungicidal PT post. Is this overkill?Thanks so much for any input! This is going to cost over $2k to build due to its length (170'), so I am am nervous about making this purchase. via /r/DIY https://ift.tt/2HbNurs
