Jump to content

Simple pitched roof on timber building


Recommended Posts

I am planning an outhouse/gardenroom/shed. It will be a basic rectangle 6.5m wide by 4m deep. e.g front and back 6.5m and the sides 4m. I want to use corrugated cladding (aesthetic reasons) on the walls and roof so I have decided to build a pitched roof and not the flat rubber one I thought I was going to build. I have cut birdsmouths before and understand the rafter calculations to get all my cuts right but I cannot find any infomation on how to tie the front and back wall together. I know my roof will be relatively lightweight but I can't help thinking that it will push the front and back walls out if they are not braced together. I want to insulate between the rafetres so that when you walk into the room and look up you see the full height, like a vaulted ceiling. I cannpt find any info on how to construct that. Am I being super dense? The stud walls will be made from 6x2 and I am hoping 6x2 will also be good for the rafters. DO I need cross members> If so where can I find details on construction options? Many thanks 

Link to comment
Share on other sites

You cannot built a vaulted roof in the same way as a traditional or truss roof. You should talk to a structural engineer about what you want to do.

 

Essentially you need a ridge beam (not a ridge board) to carry the rafters to prevent lateral thrust on the walls / reduce it to a manageable level.

  • Like 1
Link to comment
Share on other sites

Posted (edited)
28 minutes ago, George said:

You cannot built a vaulted roof in the same way as a traditional or truss roof. You should talk to a structural engineer about what you want to do.

 

Essentially you need a ridge beam (not a ridge board) to carry the rafters to prevent lateral thrust on the walls / reduce it to a manageable level.

 

thanks George. I don't want to talk to a SE about a small timber building with a lightweight roof. As I understand it you only need a ridge BEAM if your roof is 14 degrees or less. Mine is 22.5 degrees. I read that here https://todayshomeowner.com/roofing/guides/ridge-board-vs-ridge-beam/#:~:text=The ridge beam transfers the,%2F12 and 12%2F12.

Edited by Kombi Camper
Link to comment
Share on other sites

Posted (edited)

That is talking about shallow pitched roofs. The other reason for a ridge beam is if you have a vaulted roof. In which case the roof pitch is irrelevant (unless it's flat!). 

Edited by George
  • Like 1
Link to comment
Share on other sites

Posted (edited)
1 hour ago, Kombi Camper said:

As I understand it you only need a ridge BEAM if your roof is 14 degrees or less. Mine is 22.5 degrees.

That is not true, you need either ceiling joists or a ridge beam to stop wall spread.

Edited by joe90
  • Like 1
Link to comment
Share on other sites

Contact your local truss manufacturer about scissors trusses. 

 

They'll look vaulted from inside and their magic engineering software will do all the hard calcs for you. 

 

image.jpeg.d7597f05599475cf26324fc3f9d23ecf.jpeg

 

image.jpeg.2633f2adf6ca4aeb9a5f187efbda70fc.jpeg

  • Like 1
Link to comment
Share on other sites

On 13/05/2024 at 15:19, Kombi Camper said:

 

thanks George. I don't want to talk to a SE about a small timber building with a lightweight roof. As I understand it you only need a ridge BEAM if your roof is 14 degrees or less. Mine is 22.5 degrees. I read that here https://todayshomeowner.com/roofing/guides/ridge-board-vs-ridge-beam/#:~:text=The ridge beam transfers the,%2F12 and 12%2F12.

 

You could potentially use a few collar ties in the upper third of the rafters rather than full trusses or rafter ties and still insulate between the rafters and get a vaulted look.

 

That article you quote does clearly show that a tie is required though if using a ridge board:image.thumb.png.8138711ce1581acaf460200bb3e64d8c.png

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...