keithmaryq
Junior Member
- Joined
- Jan 28, 2014
- Messages
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Project:
Expanding size of existing screen room to 15' x 23', and enclosing to make 4-season room.
Details:
Screen room is 12' 6"' x 13' 6" with 3.25:12 pitch gable roof that extends off rear of home so that 3 walls are exterior. Screen room is integral to large decked areas on both sides of screen room. Construction is good quality, and saving existing roof is desired.
Work To Date:
Installed 12 footings and piers to support 3 new 23' beams extending perpendicular from house, and added floor joists for extended length of 4-season room.
Planned Work:
Add decking and sub floor to expanded area, and then construct 3 new walls while leaving existing walls in place (to support existing roof).
Problem:
Although the current rafters (2x6, 16OC) are long enough to accommodate the extended walls, I (just a DIYer) failed to account for several issues:
1. The current rafter bird mouth notches will weaken the rafters once I remove the current walls.
2. Cutting new bird mouth notches in the current rafters (24) won't be fun given their location.
3. It seems the new wall span may be at or beyond the maximum span for the current rafters -- I can't tell the wood species, but they are stamped S-P-F S-Dry No1 on some and S-P-F S-Dry 2 on others.
Possible Solution:
Sister new 2x8 rafters onto the existing rafters to increase allowable span and overcome the weakening old bird mouth notches. This method also allows for new bird mouth notches to easily be cut on the saw horses -- but I haven't determined how to notch or where to cut off existing rafters.
Note:
I also plan to add 2 evenly spaced exposed rafter ties and collar ties every 2nd or 3rd rafter right up against ridge board.
Suggestions and comments are appreciated.
Keith
Expanding size of existing screen room to 15' x 23', and enclosing to make 4-season room.
Details:
Screen room is 12' 6"' x 13' 6" with 3.25:12 pitch gable roof that extends off rear of home so that 3 walls are exterior. Screen room is integral to large decked areas on both sides of screen room. Construction is good quality, and saving existing roof is desired.
Work To Date:
Installed 12 footings and piers to support 3 new 23' beams extending perpendicular from house, and added floor joists for extended length of 4-season room.
Planned Work:
Add decking and sub floor to expanded area, and then construct 3 new walls while leaving existing walls in place (to support existing roof).
Problem:
Although the current rafters (2x6, 16OC) are long enough to accommodate the extended walls, I (just a DIYer) failed to account for several issues:
1. The current rafter bird mouth notches will weaken the rafters once I remove the current walls.
2. Cutting new bird mouth notches in the current rafters (24) won't be fun given their location.
3. It seems the new wall span may be at or beyond the maximum span for the current rafters -- I can't tell the wood species, but they are stamped S-P-F S-Dry No1 on some and S-P-F S-Dry 2 on others.
Possible Solution:
Sister new 2x8 rafters onto the existing rafters to increase allowable span and overcome the weakening old bird mouth notches. This method also allows for new bird mouth notches to easily be cut on the saw horses -- but I haven't determined how to notch or where to cut off existing rafters.
Note:
I also plan to add 2 evenly spaced exposed rafter ties and collar ties every 2nd or 3rd rafter right up against ridge board.
Suggestions and comments are appreciated.
Keith
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