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Silt Fence Stakes and T-Posts: What You Need
Silt Fence Stakes and T-Posts: What You Need and How Many
Wood stakes vs steel T-posts, how many you need, and how to space them
In This Guide
Silt fence stakes are the posts that hold the fabric upright and anchor it against runoff. Standard silt fence ships with oak stakes already attached, while wire backed silt fence is supported by steel T-posts you add separately. Choosing the right support and spacing it correctly is what keeps a fence standing through wind and heavy flow.
Quick answer: Standard silt fence includes oak stakes; wire backed fence needs steel T-posts ordered separately. Either way the rule of thumb is about 11 posts per 100 linear feet.
Steel T-post used to support wire backed silt fence.
Wood stakes vs steel T-posts
There are two common support options, and which one you need is decided by the fence rather than the site:
- Wood stakes: oak stakes driven by hand, supplied attached to standard silt fence. A 24-inch by 100-foot roll ships with eleven 36-inch oak stakes. Suited to typical job sites, residential lots, and shorter-term erosion control.
- Steel T-posts: stronger metal posts used with wire backed silt fence, which carries more weight and is built for tougher sites. T-posts are sold separately and added to wire backed orders.
Wire backed fence is available in configurations such as 36-inch and 48-inch heights with either 70 GSM fabric on 2" x 4" wire mesh or 100 GSM fabric on 4" x 4" mesh, so the fabric weight and mesh size are separate choices from the post.
The stake is longer than the fence is tall. That 24-inch fence comes with 36-inch stakes because roughly a third of each stake ends up below grade. When you are comparing products, check whether a number refers to the fence height or the stake length — they are not the same figure.
How many stakes do I need?
The working rule is 11 posts per 100 linear feet, and it applies to both support types. That is why a 100-foot roll of standard fence arrives with eleven oak stakes, and why wire backed installations are calculated at about 11 steel T-posts per 100-foot roll.
To estimate a job: measure the linear footage of the perimeter or contour line you need to protect, divide by the roll length (most fence comes in 100-foot rolls), and add extra for overlap at the seams where two runs splice together and for corners and returns. For wire backed runs, multiply your roll count by 11 to get the post count.
If your specification calls for tighter spacing, the included count will not be enough. Eleven posts across 100 feet works out to roughly 10-foot spacing. A specification asking for posts every 6 feet needs closer to 17 across the same run. Check the required spacing before you order and add stakes or posts accordingly, rather than assuming the supplied stakes cover the run.
If you are buying wire backed fence, add the T-posts to the order at the same time so you are not short on hardware at the site. The Silt Fence Selector prompts you to add T-posts when you choose a wire backed option for exactly that reason.
Spacing, depth, and which side
Three details decide whether a fence stays up.
Spacing
Closer spacing keeps the fabric taut. Standard fence is typically spaced every 6 to 8 feet; wire backed fence can run a little wider at about every 8 to 10 feet, because the wire mesh carries load between posts rather than leaving the fabric to span unsupported.
Driving depth
Drive each post deep enough into firm ground that it resists leaning or pulling out once water and sediment build up behind the fence — which is the whole reason the supplied stakes are longer than the fence height. The required embedment is a specification figure rather than a rule of thumb, so take it from your project documents.
Which side of the slope
Posts go on the downhill side of the fabric, with the fabric attached to the uphill face. That orientation matters: runoff then presses the fabric against the posts instead of pushing it off them. Along the same lines, silt fence belongs along the contour of the land, following a single elevation, rather than running straight up and down a slope — contour placement spreads water out instead of concentrating it at one point in the fence.
A note on the figures above: this article is a general guide, not a specification. Stake spacing, embedment depth, fabric weight, and trenching details on a permitted job are set by your project specification and by the rules that apply to your site, and those govern where they differ from anything here. Confirm the requirements for your project before ordering.
About our steel T-posts
Our steel T-posts are made from hot rolled rail steel (ASTM A499), or new billet with physical properties equivalent to A499. They come in a range of lengths and weights, in bare steel or painted green, and are sized to support wire backed silt fence across a full roll.
Post length is chosen the same way stake length is: tall enough to support the fabric height with enough left to drive into firm ground. Match the post length to the fence height you are installing rather than buying one length for every job.
Not sure which product fits your site? Use the Silt Fence Selector, our free interactive tool under the Resources menu, to answer a few plain-language questions and get matched to the right silt fence, height, and fabric weight for your job. For the full install sequence, see the step-by-step silt fence installation guide.
Shop Silt Fence and Steel T-Posts
Standard fence with oak stakes included, plus steel T-posts for wire backed runs. Free shipping on all orders.
Shop Silt Fence Shop Steel T-PostsFrequently Asked Questions
What stakes are used for silt fence?
Standard silt fence uses oak wood stakes that come attached to the fence. Wire backed silt fence uses steel T-posts, which are sold separately and added to the order because the heavier fence and wire mesh need stronger support.
How many stakes do I need for silt fence?
The rule of thumb is 11 posts per 100 linear feet, which is why a 100-foot roll of standard fence ships with eleven oak stakes, and why wire backed installations are calculated at about 11 steel T-posts per 100-foot roll. If your project specification calls for tighter spacing than roughly every 10 feet, you will need more than the count supplied.
Does silt fence come with stakes?
Standard silt fence comes with oak stakes already attached — a 24-inch by 100-foot roll ships with eleven 36-inch oak stakes. Wire backed silt fence does not include posts, so steel T-posts are added to the order separately.
How far apart should silt fence stakes be?
Standard fence stakes are typically spaced every 6 to 8 feet to keep the fabric taut, and wire backed fence with T-posts is often run a little wider at about every 8 to 10 feet because the wire mesh carries load between posts. Spacing on a permitted job is set by the project specification, so work from that where it differs.
Why are the stakes longer than the fence is tall?
Because part of every stake is below ground. A 24-inch fence ships with 36-inch stakes so there is length to drive into firm soil while still supporting the full height of fabric above grade. The stake length is not the fence height, which is worth checking when comparing products.
Which side of the fence do the posts go on?
Posts go on the downhill side of the fabric, with the fabric attached on the uphill face. That way runoff presses the fabric against the posts instead of pushing it off them. Silt fence should also follow the contour of the land rather than running up and down a slope.
How deep should silt fence stakes be driven?
Deep enough into firm ground that the post resists leaning or pulling out once water and sediment build against the fence, which is also why the stakes supplied are longer than the fence height. Required embedment depth is set by your project specification, so use that figure rather than a general one.
Post counts and spacing figures in this guide are general estimating rules. Product contents and dimensions vary by model and change over time, so confirm the stake count and length on the product listing for the fence you are ordering, and work to your project specification for the installation itself.