How would you frame this in for windows?

[Pat Barry]

At my cabin there is an enclosed porch with a shed roof. There are currently two sliding glass storm windows about 6 ft wide by 3 1/2 ft tall. I want to replace these with three new Pella sliders about 4 ft wide by 4 ft tall. The present header is a log about 4 in diameter with posts at each end and in the center. Then, each window is framed inside 2x6s but not a traditional framed header. I'd like to leave the log header and install three windows with two posts using 2x6s for the load bearing wall and frame for the windows under the log header. I don't want to add an additional double 2x6 header over each window because that will take too much of the available height, lowering the window too much. The present architecture has been there for 40 years without incident. How important is the standard building method in this situation?

[Tom M King]

Sounds like you're shortening the span that it has been using, so I don't see any problem. It would be stronger than it was, going from 6' spans to 4'.

[Paul F Franklin]

If there are no signs of sag or deflection in the 4" log you will probably be fine. If you want bullet proof, figure out how to incorporate and support a steel lintel under the log. That won't lower the window more than 3/4 of an inch or so.

[sean meltvedt]

Pat if this is a traditional log wall, then the 2x frame would be shorter than the opening to allow for movement of the logs with humidity changes without causing the windows to bind.
Cheers
Sean

[Pat Barry]

Thanks guys for the feedback. I was thinking similarly that with shorter spans (4 ft vs 6 ft) it should be OK.

Sean, the construction is more similar to standard framing with vertical 4 in dia logs on 24" centers. The horizontal log above the existing windows is the header.

[scott vroom]

Pat, is that 4" log supporting the shed roof load? What is the unsupported span width?

At my cabin there is an enclosed porch with a shed roof. There are currently two sliding glass storm windows about 6 ft wide by 3 1/2 ft tall. I want to replace these with three new Pella sliders about 4 ft wide by 4 ft tall. The present header is a log about 4 in diameter with posts at each end and in the center. Then, each window is framed inside 2x6s but not a traditional framed header. I'd like to leave the log header and install three windows with two posts using 2x6s for the load bearing wall and frame for the windows under the log header. I don't want to add an additional double 2x6 header over each window because that will take too much of the available height, lowering the window too much. The present architecture has been there for 40 years without incident. How important is the standard building method in this situation?

[Pat Barry]

Pat, is that 4" log supporting the shed roof load? What is the unsupported span width?

Hi Scott, yes it is supporting the roof over a length of about 14 ft end to end with a center support between the two existing windows. Tjat center support will be removed and replaced with two supports (one on each side of the new center window). So it will be new 2x6 framed corner, 4 ft window, vertical studs, 4ft window, vertical studs, 4ft window, framed corner. Likely will have three vertical studs between each window pair to act as posts supporting the existing 4" log header.

[Rob Charles]

As Tom said in 2nd post above, decreasing the span from 6' to 4' should not be a problem. But, follow the load path to the foundation to insure that adequate structure exists under the areas where you propose to install the new posts/studs. From the "enclosed porch with shed roof" description, my mind conjures up a mental picture of a porch supported on piers vice a continuous foundation. If that is the case and the current single post is above a pier and you are relocating the posts/studs off that pier, go slow & consult a pro. Even with a continuous foundation, ensure that adequate blocking exists under the floor to take the compression loads to the foundation.

[Pat Barry]

As Tom said in 2nd post above, decreasing the span from 6' to 4' should not be a problem. But, follow the load path to the foundation to insure that adequate structure exists under the areas where you propose to install the new posts/studs. From the "enclosed porch with shed roof" description, my mind conjures up a mental picture of a porch supported on piers vice a continuous foundation. If that is the case and the current single post is above a pier and you are relocating the posts/studs off that pier, go slow & consult a pro. Even with a continuous foundation, ensure that adequate blocking exists under the floor to take the compression loads to the foundation.

Good feedback Rob. It is, as you suspected, a post/pier construction. I will look at that closer for that wall. Other places under the cabin have larger 8" diameter log beams between posts/piers and I therefore suspect this will be similar.