Need to build your privacy fence on a slope? It’s not hard as long as you plan and build carefully. You have four options. You get to decide which is best for you. Here they are:
Level Rails, Level Pickets: As my amazing drawing below shows, this method gives the top of the fence line a stair-step look. The tops of the pickets will be more stable and supported than the bottoms of the pickets. You could strengthen the bottom of the fence with a rot board running parallel to the ground. Using level rails means you either have to put your rails closer together or use fewer rails.
Level Rails, Sloped Pickets: The top of the fence line is parallel to the ground but the tops and the bottoms of the pickets are left unsupported. You can strengthen the fence pickets at the top with a top rail, which also makes the fence look nice, and you can strengthen the bottom with a rot board.
Sloped Rails, Sloped Pickets: I like this one the best but you have to decide how level you want the top of the fence. Do you want to trim the tops off the fence pickets or do you want to leave them untrimmed with a small rise from picket to picket? It’s up to you and it barely matters. This is my favorite method because it easily allows for three rails AND the pickets are well-supported from top to bottom along the length of the fence.
Sloped Rails, Level Pickets: This is my second favorite method because it allows for three rails but the drawback is that you still end up with pickets that are unsupported at their tops. If you want the stair-step look in your fence, this is probably the way to go.
IMPORTANT (REALLY): If you are building a gate on the slope portion of your fence, put the hinges on the DOWNHILL side so it will open towards the downhill side instead of swinging into the hill.
Level Rails versus Sloped Rails:? Unless you are building your fence on unusually rough or unlevel terrain, I would suggest always sticking with sloped rails and sloped pickets. Levels rails are easier to build if you are building in an area where you have to move a lot of rocks or something. Some people might just prefer the straighter lines of the level pickets.
Whichever method you choose to build your fence on a slope, you can use a rot board at the bottom to strengthen the fence and protect the bottoms of the pickets and a top rail will improve the looks of your fence and provided additional strength up there as well. Screws are better than nails and always use properly treated wood.
Here are more tips on how to build a fence that lasts.
Sloped rails/Level Pickets are the way to go. Especially if your building a Convex Top. Just make sure the tallest picket doesn’t extend more than 7″ above the top rail. If your building any style flat top picket fence, make sure the pickets don’t extend more than 5-6 inches above the top rail. I have been using three rails on all 4′ fences for two years. I have even built 6′ fences w/4 rails (probably overkill).
The biggest mistake most fence companies make is to not bury posts 1/3 of their total length. “No shortcuts”, buy longer posts and cut them. Always set finished top posts at least 3″ taller than the highest finished top picket. 1 1/2″ spacing between pickets. Don’t markout for picket spacing. Use a 1 1/2″ round PVC pipe.
Pour concrete dry then add 15 seconds of hose water to each post. Hose off all concrete dust from the posts. Don’t nail for at least 48 hrs. Use top string and bottom string when leveling posts. Use stainless steel nails. I could ramble on forever. Build 7′ sections. Use a 8″ auger bit. 60 lbs. concrete per hole. I own Superior Fence Co. in Mechanicsville, Va.
There you have it, folks! Thanks, David. Good stuff.
In responses to Dave Eilertson’s post I have one concern with the common practice of pouring dry concrete into the hole. In a bag of ready mix concrete the actual cement tends to settle again the sides of the bags as it so fine compared to the rock, therefore it doesn’t get evenly mixed into the footing and won’t be as strong. Although it takes longer, I premix then pour.