In my back yard we have a covered patio that is covered by our roof. There are two support post in the middle. i'm going to be building a pergola at the end of the roof that will extend out another 8ft. I would like to remove the two middle support post to really open up the space but not quite sure what I should do with the current 4x6 beam that spans 25ft for my current covered patio. Should i remove two middle post and sister in another 2x6 or remove middle post and replace the whole beam with a couple 2x8?
find it hard to believe you can remove the center beam without wearing the roof to the emergency room.
last time I saw this on TV, they had to sister a C-beam of steel and put support on the outer edges. it comes down to whatever your engineer requires... and to permit this, the city is either going to tell you what to do, or require plans with an engineer's stamp.
sig: if this is a new economy, how come they still want my old-fashioned money?
The only reason that your current 4x6 beam works over a 25' span is because it's supported in two other places by those posts you want to remove. While it is possible to beef up the beam and remove the posts, the load on a 25' beam will be huge. You'll need some on-site engineering to confirm what size but if you stay with a wooden beam, expect something in the 4x18 size to span that 25'.
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