Rooflight opening size

[Yorkblade]

Hi,

We are just in the process of laying the rafter for the lean to roof, we will e doubling up where the rooflights are buy in respect to the opening size is it a case of the window dims + 40mm or something else?

Also, are coach bolts required for fastening the doubled up timbers together?

Thank you

 

[RonnyRaygun]

The rooflights will come with fitting instructions and they will tell you what gap to leave.

BC will insist that you use coach bolts to bolt the trimmers, and it's a standard detail, but I nailed mine together on my extension with lots of 3" ring shank nails from both directions (because while I'm a structural engineer, I'm also very lazy, and I knew I could prove the capacity of the nails if I needed to). They didn't object...

 

[Notch7]

The rooflights will come with fitting instructions and they will tell you what gap to leave.

BC will insist that you use coach bolts to bolt the trimmers, and it's a standard detail, but I nailed mine together on my extension with lots of 3" ring shank nails from both directions (because while I'm a structural engineer, I'm also very lazy, and I knew I could prove the capacity of the nails if I needed to). They didn't object...

tut tut

……. architects and S/Es moan when builders don’t follow the plans exactly

 

[RonnyRaygun]

tut tut

……. architects and S/Es moan when builders don’t follow the plans exactly

I'm not sure I specified how to fix the trimmers together on the approved plans

 

[catlad]

If using velux skylights then you need to leave 30mm each side, if you don't you will struggle to fit the insulation collar.