--- title: Can the power fan hole be square instead of round? description: It's best if the power fan airflow hole is round instead of square. --- [Skip to content](https://help.gibraltarbuildingproducts.com/en/knowledge/can-the-power-fan-hole-be-square-instead-of-round#main-content) English Show submenu for translations ![GBAD Full Color.png](https://blog.stealthbond.com/hubfs/GBAD%20Full%20Color.png) Open main navigation Close main navigation - English Show submenu for translations - Go to www.gibraltarbuildingproducts.com Go to www.gibraltarbuildingproducts.com Hello. How can we help you? - There are no suggestions because the search field is empty. 1. [Help Center](https://help.gibraltarbuildingproducts.com/en/knowledge?hsLang=en) 2. [Ventilation](https://help.gibraltarbuildingproducts.com/en/knowledge/ventilation?hsLang=en) 3. [Power Fans](https://help.gibraltarbuildingproducts.com/en/knowledge/ventilation?hsLang=en#power-fans) # Can the power fan hole be square instead of round? ## It's best if the power fan airflow hole is round instead of square. It is best if the power fan airflow hole is cut round. If the hole is cut to a 14" diagonal, the hole will be too small. It will leave the sides too short and block off some of the round opening in the fan. If the hole is cut with 14" sides, then in the corners of the square hole the round opening will be unsupported and can lead to additional vibrations since the metal can flex while the fan is running. The best case with our roof-mount fans is using a round hole, as this both ensures maximum effective use of the opening of the fan so long as it is 14" in diameter and supports the entire opening with material of the roof deck to reduce potential vibrations. - [Metal Roofing](https://help.gibraltarbuildingproducts.com/en/knowledge/metal-roofing?hsLang=en#main-content) - [Metal Roofing](https://help.gibraltarbuildingproducts.com/en/knowledge/metal-roofing?hsLang=en#metal-roofing) - [Oil Canning](https://help.gibraltarbuildingproducts.com/en/knowledge/metal-roofing?hsLang=en#oil-canning) - [SMRIB Profile](https://help.gibraltarbuildingproducts.com/en/knowledge/metal-roofing?hsLang=en#smrib-profile) - [5V Crimp Profile](https://help.gibraltarbuildingproducts.com/en/knowledge/metal-roofing?hsLang=en#5v-crimp-profile) - [Job Packs](https://help.gibraltarbuildingproducts.com/en/knowledge/metal-roofing?hsLang=en#job-packs) - [Roofing Accessories](https://help.gibraltarbuildingproducts.com/en/knowledge/metal-roofing?hsLang=en#roofing-accessories) - 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