Ridge beam

[SAS-it]

I’m going to replace two existing roofs, both to be vaulted ceiling with velux windows. They meet each other with a valley / box gutter.


I friend of a friend has done the structural calculations but I have still have a few questions.


Roof 1 (inside size 11ft by 7ft)

Ridge 50 * 170 * 7ft c24

Rafters 50 * 125 c24

Two velux , one each side (MK04)


Roof 2 (inside size 11ft by 12ft)

Ridge 63 * 225 * 12ft c24

Rafters 50 * 125 c24

Four velux two each size (MK04)



Q1) can I use larger ridge beam e.g 75 * 225 instead of 63 as it’s easier to get.


Q2) can the rafters attach to the side of the ridge beam or does the beam have to be under the rafters with notches cut out of the rafters


Q3) can I user larger rafter e.g. 50 * 150 instead of 125, to allow for the insulation and can the bird mouth cuts be deeper so the extra depth is in the inside of room.


Thanks

 

[^woody^]

Yes
Yes
It depend if your friend has used the weight of 125mm joists and the calculation, and it just worked with those. But this is a slim possibility.