Increase Garage Roof Slope - Could this Work?

[nameloser]

Hello, it's time to replace the roofing paper on our low-slope garage roof and I thought I'd take the opportunity to slightly increase the slope.

I was planning to use 45×225 in the same length as the current beams, cut them diagonally, and then screw-glue onto the existing ones according to the principle sketch:



Then lay rough boards as we have today but upgrade to 23×95 instead of today's 20×95.

Does anyone see issues with such a solution?
I would be very grateful for input.

 

[Rickard.]

It will work fine, I mostly prefer working with strips of sheet products (plyfa or OSB) instead of nailplates, but both work.

Choose 120mm wide tongue and groove boards and double nail everything!

 

[Mindboggle]

As a happy amateur, I would like to suggest that you should screw instead of nail.

I helped my neighbor replace the felt on such a roof where the nails had moved upward and punctured the felt.

 

[Rickard.]

As a happy amateur, I want to suggest that you should screw instead of nail.

I helped my neighbor replace the felt on such a roof where the nails had worked their way up and punctured the felt.

Nails working their way up is almost always due to the nail being undersized, for sheathing, you should use 75mm wire nails or equivalent machine nails.

Screwing sheathing is not something you should do, but you absolutely can do it

 

[Mindboggle]

Could very well have been the wrong type of nail on the neighbor's roof.

The slope of the neighbor's garage roof was constructed almost as your description, but without the raw boards.

Tar paper, sloped battens, metal roof.

Correction:
The battens were nailed and the nails walked out from the battens through the metal roof, not the tar paper.

Probably it got quite hot between the metal roof and the tar paper.