Product Description
Adapter Blocks for Standard 4-Lag Post Mounts – Fit 5" & 6" Vinyl Posts
- Adapt 4" post mounts to larger vinyl posts — These adapter blocks allow you to use Superior Outdoor Products’ 4" Standard 4-Lag Post Mounts (models 8436G-NT and 8442G-NT) with 5" or 6" vinyl posts instead of a 4" post.
- Secure fit around the post mount — Blocks are designed to fill the gap between the 4" structural post mount and larger 5" or 6" vinyl sleeves, helping reduce play and creating a snug, supported post core.
- Clean, finished appearance — Properly sized adapter blocks center the post sleeve on the mount so the finished post looks straight, uniform, and professionally installed.
- Works with standard 4-lag structural mounts — Specifically configured for use with Superior’s 4" Standard 4-Lag Post Mounts, making it easy to integrate 5" or 6" railing or fence posts into your existing system.
- Ideal for railing and fence posts — Use adapter blocks wherever 5" or 6" vinyl posts are installed over 4" structural post mounts on decks, porches, balconies, or similar flat surfaces.
- Simple to install — Blocks slip over or around the 4" structural tube and sit between the post mount and the inside wall of the larger vinyl post, with no special tools required beyond what’s used for the post mount itself.
Adapter Blocks for Standard 4-Lag Post Mounts make it easy to combine Superior Outdoor Products’ structural 4" post mounts with larger 5" or 6" vinyl posts for a more substantial look and added design flexibility. Instead of sourcing a different mount for every post size, you can use the same 4" structural base (8436G-NT or 8442G-NT) and bridge the gap to your 5" or 6" sleeve with correctly sized adapter blocks. The result is a centered, solid-feeling post that looks clean from all sides and supports code-focused vinyl railing or fence applications when used as part of a properly designed system.
Specifications
| Attribute | Details |
|---|---|
| Brand | Superior Outdoor Products |
| Product Type | Adapter blocks for structural 4-lag post mounts |
| Compatible Post Mounts | 4" x 36" (8436G-NT) and 4" x 42" (8442G-NT) Standard 4-Lag Post Mounts |
| Post Sizes Supported | 5" vinyl posts • 6" vinyl posts (sleeved over 4" structural mounts using adapter blocks) |
| Typical Applications | Vinyl deck, porch, balcony, and stair posts where larger 5" or 6" sleeves are used over 4" structural mounts |
| Function | Centers and supports larger vinyl post sleeves on 4" structural mounts; helps reduce movement and improve fit |
| Mount / Railing System | Designed as an accessory for Superior Outdoor Products vinyl railing and newel post systems using 8436G-NT / 8442G-NT mounts |
| Sold As | Adapter block components only; structural post mounts, post sleeves, caps, trim, and anchoring hardware sold separately |
Installation
Start by installing your 4" Standard 4-Lag Post Mounts (8436G-NT or 8442G-NT) according to the manufacturer’s instructions, using appropriate structural anchors for the deck or concrete surface and leveling the mounts plumb. Once the mounts are secure, position the adapter blocks around or over the 4" post tube at the locations recommended by your system layout to center the larger 5" or 6" vinyl sleeve. Slide the vinyl post sleeve down over the adapter blocks and post mount, ensuring a snug fit with no significant gaps. After the posts are plumb and sleeves are fully seated, attach your vinyl railing brackets or fence rails per the railing/fence installation guide and finish with compatible post trim and caps as desired. Always follow local building codes and Superior’s installation documents when using structural mounts and adapters in guard or handrail systems.
Frequently Asked Questions
What do these adapter blocks do?
These adapter blocks allow you to use Superior’s 4" Standard 4-Lag Post Mounts with larger 5" or 6" vinyl posts by filling the space between the 4" structural tube and the inside of the bigger post sleeve.
Which post mounts are they designed to work with?
They are intended for use with Superior Outdoor Products 4" Standard 4-Lag Post Mounts, models 8436G-NT (36") and 8442G-NT (42"), used under vinyl newel posts.
Can I use these adapter blocks with 4" posts?
No. 4" posts sleeve directly over the 4" Standard 4-Lag Post Mounts and don’t require adapter blocks. These blocks are for 5" and 6" posts that are larger than the structural mount.
Are the post mounts included with the adapter blocks?
No. Adapter blocks are sold separately from the structural post mounts. You’ll need to purchase the 8436G-NT or 8442G-NT mounts and any vinyl post sleeves, caps, and trim you plan to use.
Can these adapter blocks be used on both level and stair posts?
Yes. As long as the post is a 5" or 6" vinyl post installed over a compatible 4" Standard 4-Lag Post Mount, the adapter blocks can be used in both level and stair applications.
Do the adapter blocks change the structural rating of the post mount?
The adapter blocks are intended to work as part of a tested structural post-mount system, but they do not replace the need to follow the manufacturer’s installation instructions and local building codes. The overall system performance still depends on correct installation of the 4-lag post mount, anchors, and railing.
