Post cap (post top)Tapped on, then held by a dab of glue or silicone.
Line postRails enter holes routed in two opposite faces.
Top railCloses the upper ends of the pickets and slides into both posts.
Bottom railThe pickets stand in its slot, and it holds the aluminum insert.
PicketMakers also call it a board or a panel.
Concrete (footing)Poured around the post, stopping just below ground level.
Fence and footing 6
LatticeA strip held between mid rail and top rail.
Mid rail (middle rail)Sits under the lattice. The tallest plain sections add one too.
End postRouted on one face only, because the fence stops here.
GravelGoes into the hole first, under the post, for drainage.
Ground clearanceAbout 2 inches, so the rail never rests on the soil.
Post insertAn aluminum channel inside a post that carries a gate.
Inside a line post 3
Routed holeThe opening in the post wall that a rail end slides into.
Rail notchCatches behind the post wall so the rail cannot pull out.
Rail insert (aluminum insert)An aluminum channel that slides inside the bottom rail to stiffen it.
Pickets from above 3
U-channelCovers the open edge of the first and last picket.
TongueThe lip on one edge. It slides into the next picket's groove.
GrooveThe slot on the other edge, which takes the next picket's tongue.
How this list was compiled: Part names and every detail line were checked, for facts only and with nothing copied, against pages and documents read on 2026-09-20; the names were read again on 2026-09-30 in guides A, B and C, in Synthetic fence and in https://en.wikipedia.org/wiki/Chain-link_fencing (line posts are those set between the terminal posts; end, corner and gate posts; posts set on a concrete footing). Wikipedia: https://en.wikipedia.org/wiki/Synthetic_fence (vinyl or PVC fencing is sold mostly as extruded profiles; home products are usually hollow; better components are ribbed or carry reinforcements, often of aluminium; rails or pickets slide into slots and grooves made for them; posts go into pre-dug holes or are slid over a pre-set wood, rebar or pipe post). Three makers' installation guides that do not share a text, each found from the maker's own site. Guide A, index https://weatherables.com/pages/installation-care, document https://cdn.shopify.com/s/files/1/0942/4470/0531/files/Fencing_Master_Instructions_2024_c38fd533-37f7-4006-ad2a-1713bc10b748.pdf?v=1767201152 (line, end, corner and blank posts; an end post has a blank side; routed holes and the routed opening of the post; the slotted bottom rail with the aluminum insert; tongue-and-groove pickets slid between the bottom and top rails; a U-channel slid onto the first and last picket; notches on the rail ends; the mid-rail with a lattice strip between it and the top rail; post caps held with a little clear silicone; a minimum 2 inch clearance under the panel; concrete filled to a little below ground level; an aluminum post insert or a concrete fill for the hinge post of a gate; panel used for the whole section). Guide B, index https://www.catalystfence.com/resources/installation-instructions/, document https://www.catalystfence.com/wp-content/uploads/CAT-BOM-34111483-Privacy-Vinyl-Fence-Kit-1-25-WEB.pdf (component list of rails, boards, U-channels, pickets, lattice, posts and post tops; gravel in the hole first, then the post, then concrete; a ground clearance of 2 inches that allows for normal expansion and contraction and keeps soil from damaging the fence; the aluminum insert placed in the bottom rail, which then goes into the bottom post route hole; some kits need no insert and the tallest put one in the middle rail; the U-channel on the tongue side of the first board and the groove side of the last; glue on the post tops; a vinyl post placed over a driven steel pipe with collars as a no-dig way; panel used for the whole section). Guide C, product page https://superioroutdoors.com/boston-vinyl-privacy-fence, document https://drive.google.com/file/d/1rfEDZxm_s3YrJyNOS72Yl-4MyXG0mtB1/view (top and bottom rails, an optional middle rail on the tallest heights, caps tapped on with a mallet and glued, a lattice accent; the routed post hole; the string line 2 inches above ground; concrete stopped about 2 inches below the surface; the U-channel, which this guide also calls a C-channel and screws to the post; tongue and groove panels, its word for the single boards, with section for the whole bay; the top rail inserted until it locks into place; rail ends notched with a notching tool, and the crimps pressed in to take a rail back out; aluminum post channels inside each post that supports a gate). Also read and not counted as a fourth voice, because it shares most of its text with guide A: https://www.vinylfenceanddeck.com/wp-content/uploads/2024/09/vinylfenceinstallationinstructions-1.pdf, found from https://www.vinylfenceanddeck.com/help-center/vinyl-fence-installation-instructions/ (top-view drawings of line, corner, three-way and blank posts and their routing; the bottom rail is the one with aluminum; the notches stop the rails pulling out of the posts; pea gravel at the bottom of each hole for drainage). The public summary page of the standard for these profiles, https://store.astm.org/f0964-13.html, was read only for its title and scope (rigid PVC exterior profiles used for fencing and railing; posts, rails and pickets are the primary members and caps and brackets are accessories); nothing from it is printed. Dead or closed on 2026-09-20: hooverfence.com (403), weatherables.com/pages/installation-instructions (404), barretteoutdoorliving.com/resources/installation-instructions (404), the wambamfence.com glossary (404). The American Fence Association publishes no glossary that could be found. No maker is named on the page. Licence: own work
The drawing: Drawn for this site on 2026-09-30 from plain geometry. Own original schematic drawing of a composite teaching fence; nothing traced or copied, and no maker's figure was redrawn. Licence: own work
How it works
The parts of a vinyl fence slot together as a kit. Rails slide into holes routed in the posts, and pickets stand between them. Four drawings show the fence from the front, a post in the ground, a post cut open, and pickets from above.
Read the full guide
What are the parts of a vinyl fence called?
Six names cover a plain privacy section: post cap, line post, top rail, bottom rail, picket and the concrete round each post. Start here: 6 main parts asks those. The right-hand section adds a strip of lattice held between the top rail and a mid rail. The second drawing cuts the soil away to show the concrete and the gravel under a post.
What holds a vinyl fence together?
Each rail end slides through a routed hole, and a rail notch catches behind the post wall so the rail cannot pull out. An aluminum rail insert stiffens the bottom rail. Pickets join edge to edge, tongue into groove, and a U-channel covers the open edge of the first and last one.
Check what panel means before you order. Some guides use it for one board, others for the whole section between two posts.
A line post is routed on two opposite faces, an end post on one, and a corner post on two faces that meet.
Questions and answers
What is the metal piece inside a vinyl fence rail?
It is the rail insert, part 15: an aluminum channel that slides inside a rail to stiffen it. Most kits put it in the bottom rail. Some tall sections add one to the mid rail, and some kits need none.
Are vinyl fence posts hollow?
Yes, most home vinyl posts are hollow. They are set in concrete in a dug hole, or slid over a wood post or steel pipe fixed in the ground first. A post that carries a gate gets an aluminum post insert or a concrete fill.
What is the U-channel on a vinyl fence for?
It covers the open edge of the first and last picket in a section, where the pickets meet a post. Some guides slide it onto the picket, and others screw it to the post first.
Why is there a gap under a vinyl fence?
All three makers' guides read for this page set the bottom rail about 2 inches above the ground. One says the gap allows for normal expansion and contraction and keeps soil from damaging the fence.