Separate firings or trim bigger joists?

[i_am_fubar]

I have a flat roof that needs 175mm deep joists (Based on span) plus a 50mm firing.

As the beams will be visible inside, I am considering whether to cut the firings separately and fit them, or get 225mm deep joists and taper them.

Is the latter at all considered acceptable?

Ta,
Fubar

 

[Notch7]

I have a flat roof that needs 175mm deep joists (Based on span) plus a 50mm firing.

As the beams will be visible inside, I am considering whether to cut the firings separately and fit them, or get 225mm deep joists and taper them.

Is the latter at all considered acceptable?

Ta,
Fubar

If you want them as visible beams then do 225mm and taper them, so you don’t see a joint.

You could just do 175mm and have them tilted, but I guess you want the underside of the beams level