Sistering rafters

[Gary009]

Hi, iv received some drawings to sister some 100mm rafters with 200mm rafters for added strength in a loft. Surely this won’t work with the deeper timber over the plate? There will be a stud wall at mid span acting as a purlin but I can’t get my head round the main plate detail unless just a seat cut which will effectively make it the equivalent of 100mm again or am I reading Tom much into it? Thanks

[joe90]

Sistering is all about stopping deflection (bending) which the added 200mm will sort so don’t worry about the wall plate only resting on 100mm 👍

[Gary009]

Thanks Joe, much appreciated 👍

[SteamyTea]