Octagonal Timber Roof
Posted: Wed Jun 08, 2022 8:39 am
I needed to replace the roof of my octagonal gazebo which was damaged in a storm. The roof is a timber frame, and will have a coloursteel roof (when the steel arrives!)
I looked around for a CAD program to design it with. I was convinced by FreeCAD because it is parameter driven (and free). I wanted to make the roof pitch slightly higher than the original, and in any case the old roof was too distorted to measure from.
So I looked online for an octagon calculator so that I could derive the various dimensions from 2 simple bases: the rafter pitch (27deg) and the inside wall width (1248mm). I dusted down some schoolboy trigonometry from 60 years ago, and set about calculating the dimensions, and drawing the rafters, noggins and fascia from them. All using the dimensions calculated in the spreadsheet from the basic sizes. What a lot of triangles!
I was a complete beginner with FreeCAD (or any other CAD) and owe a debt of gratitude to all those who patiently dealt with a newbie, and answered his questions.
I attach the FCStd file, and a picture of the roof timbers constructed from the FreeCAD drawings. My builder was impressed that the angles for the timber saw cuts were spot on!
Ken
OS: Windows 10 Version 2009
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24267 +148 (Git)
Build type: Release
Branch: Branch_0.19.4
Hash: 476ecf091941bead59b14e44afa6064d5a66afa3
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.3
Locale: English/New Zealand (en_NZ)
I looked around for a CAD program to design it with. I was convinced by FreeCAD because it is parameter driven (and free). I wanted to make the roof pitch slightly higher than the original, and in any case the old roof was too distorted to measure from.
So I looked online for an octagon calculator so that I could derive the various dimensions from 2 simple bases: the rafter pitch (27deg) and the inside wall width (1248mm). I dusted down some schoolboy trigonometry from 60 years ago, and set about calculating the dimensions, and drawing the rafters, noggins and fascia from them. All using the dimensions calculated in the spreadsheet from the basic sizes. What a lot of triangles!
I was a complete beginner with FreeCAD (or any other CAD) and owe a debt of gratitude to all those who patiently dealt with a newbie, and answered his questions.
I attach the FCStd file, and a picture of the roof timbers constructed from the FreeCAD drawings. My builder was impressed that the angles for the timber saw cuts were spot on!
Ken
OS: Windows 10 Version 2009
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24267 +148 (Git)
Build type: Release
Branch: Branch_0.19.4
Hash: 476ecf091941bead59b14e44afa6064d5a66afa3
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.3
Locale: English/New Zealand (en_NZ)