--- title: Smith Roof Drain Optional Variations - Underdeck Clamp description: Learn more about the Smith underdeck clamp, a roof drain optional variation. --- Search our inventory of drains, drain parts, safety and roofing equipment, and accessories. [Shop Now](https://hy-techroof.com/products/). - [ About ](https://www.hy-techroof.com/about-hy-tech/) - [ Contact ](https://www.hy-techroof.com/contact-hy-tech/) - - [![Hy-Tech Roof Products](https://resources.hy-techroof.com/hubfs/Logos/Hy-Tech%20Logo_rgb_maroon_480.png) ](https://www.hy-techroof.com) [**](https://www.hy-techroof.com/login.php) [**](https://www.hy-techroof.com/cart.php) ** ** [![Hy-Tech Roof Products](https://resources.hy-techroof.com/hubfs/Logos/Hy-Tech%20Logo_rgb_maroon_480.png) ](https://www.hy-techroof.com) [**](https://www.hy-techroof.com/cart.php) - - # Smith Roof Drain Optional Variations - Underdeck Clamp **![Underdeck Clamp](https://resources.hy-techroof.com/hs-fs/hubfs/2022%20Hy-Tech%20Website/Roof%20Drain%20Specs%20Pages/Smith%20Drain%20Specs/Smith%20Drain%20Resources/Underdeck%20Clamp.png?width=350&name=Underdeck%20Clamp.png)** ## **Underdeck Clamp (-C)** The underdeck clamp should be specified on all but poured-in-place installations. Roof drains must be firmly secured to the roof with an underdeck clamp. Otherwise, due to snow loads, rain loads, and regular expansion and contraction, the drain will work in and out of the roofing, causing roofing membranes to flex and fail. Brittle tar will crack and leaks will occur.  ![L Shaped Underdeck Clamp](https://resources.hy-techroof.com/hs-fs/hubfs/2022%20Hy-Tech%20Website/Roof%20Drain%20Specs%20Pages/Smith%20Drain%20Specs/Smith%20Drain%20Resources/L%20Shaped%20Underdeck%20Clamp.png?width=350&name=L%20Shaped%20Underdeck%20Clamp.png) ## "L" Shaped Underdeck Clamp (-CL) A "L" shaped underdeck clamp (-CL) is available for use when the regular underdeck clamp is not acceptable.Specify the "L" shaped underdeck clamp when the deck thickness is less than the minimum dimension shown for the regular underdeck clamp. This is particularly applicable for roof drain installations in metal roof decks. [![Find and Buy Smith Roof Drains](https://no-cache.hubspot.com/cta/default/10783/8114ace5-1719-482e-8b86-7f1517b618a7.png)](https://cta-redirect.hubspot.com/cta/redirect/10783/8114ace5-1719-482e-8b86-7f1517b618a7) - [Drains](https://www.hy-techroof.com/products/drains/) - [Zurn](https://www.hy-techroof.com/manufacturers/zurn/) - [Smith](https://www.hy-techroof.com/manufacturers/j-r-smith/) - [Josam](https://www.hy-techroof.com/manufacturers/josam/) - [Wade](https://www.hy-techroof.com/manufacturers/wade/) - [Marathon](https://www.hy-techroof.com/manufacturers/marathon/) - [Olympic](https://www.hy-techroof.com/manufacturers/olympic/) - [Equipment](https://www.hy-techroof.com/products/equipment) - [Garlock](https://www.hy-techroof.com/manufacturers/garlock/) - [Leister](https://www.hy-techroof.com/manufacturers/leister/) - [All Seasons / Grizzly](https://www.hy-techroof.com/manufacturers/all-seasons-equipment/) - [Hennes-Johnson](https://www.hy-techroof.com/manufacturers/hennes-johnson/) - [Gator](https://www.hy-techroof.com/manufacturers/gator-roofing-equipment/) - [Roofmaster](https://www.hy-techroof.com/manufacturers/roofmaster-products-company/) - [Safety](https://www.hy-techroof.com/products/safety) - [Leading Edge](https://www.hy-techroof.com/manufacturers/leading-edge-safety/) - [Tie Down Manufacturing Ingenuity](https://www.hy-techroof.com/manufacturers/tie-down-manufacturing-ingenuity/) - [Malta Dynamics](https://www.hy-techroof.com/manufacturers/malta-dynamics/) - [Resources](https://resources.hy-techroof.com) - [Account](https://www.hy-techroof.com/login.php) - [The Drain Wizard](https://resources.hy-techroof.com/ask-the-drain-wizard) - [FAQ](https://resources.hy-techroof.com/faq) - [Blog](https://resources.hy-techroof.com/blog) - [Roof Drain Specs](https://resources.hy-techroof.com/roof-drain-specs-and-diagrams) - [Video Library](https://resources.hy-techroof.com/video-library) - [About](https://www.hy-techroof.com/about-hy-tech/) - [Contact Us](https://www.hy-techroof.com/contact-hy-tech/) - [About Hy-Tech](https://www.hy-techroof.com/about-hy-tech/) - [Service and Repairs](https://www.hy-techroof.com/service-and-repairs/) [800-635-0384](tel:8006350384) **Hy-Tech Products **10035 Broadview Road, Broadview Heights, OH 44147 [info@hy-techroof.com](mailto:info@hy-techroof.com) [800-635-0384](tel:8006350384) **Hy-Tech Products **10035 Broadview Road, Broadview Heights, OH 44147 [info@hy-techroof.com](mailto:info@hy-techroof.com) © 2026 Hy-Tech Products, Inc. All rights reserved. [ Terms of Use ](https://resources.hy-techroof.com/terms) - -