Increasing & moving loft hatch Question

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Hi I want to install a new loft hatch over the next few days. Its bigger than the existing and I want to move it slightly.

Is the below the correct way to go about it and is sistering a new timber to the existing as shown required?

 

[Deleted member 174758]

Before you start, one question has to be "What is the structure of your roof?" Is it made up of Fink trusses?

 

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Traditional roof as below

 

[Deleted member 174758]

In that case your proposed scheme would work, but you should double (or possibly treble) the new trimmers, shown in blue

 

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I had planned on doubling them bolting 2nr 4x2 together. Will that be sufficient or should I bolt a 3rd?

Is there any benefit in increasing timbers to 5x2 or 6x2 if the existing is all imperial 4x2

Also are the additional timbers shown in green required or a waste of time

 

[Deleted member 174758]

Stick with the size of the current joists