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Discussion Starter · #1 ·
All,
Need some guidance/ideas on what I can do with my flooring joists for my attic.

Basically I live in a ~28X52 ft long ranch style rectangle home built in 1952. My family has owned it since 1952 (second owners). The house is concrete block construction. The interior is 2X4 with R15 insulation and 5/8 drywall throughout (recently remodeled). There is a center load bearing wall that goes right down the middle of the home the complete length. The Floor Rafters in the attic go from this load bearing wall to basically the top of the Concrete Block exterior wall. The span (end to end) of the 2X6 floor rafter lumber measures at 14ft. Also both ends of the rafter are square not angled cut. I would also like to add that during the total remodel of the large living room (1/4 of house) that the existing 2X6s were sister joisted with 2x6s with the goal to someday floor the attic.

There is a large area available in the attic. I am 6 ft and I cannot touch the roof peak even if I try. If you make the walls ~4ft tall (a cape cod style second floor)... I believe there is a ~12X52 room upstairs. I would like to change this area into a large family room with a small home office at one end.

The problem I am having is the floor. The span charts I am reading are telling me 2X8 for a 14ft span. Does the span number take into account that my attic walls will come down ~ in the middle of the span?

So from point of attic wall drop to the load bearing wall first floor the distance is like 6-7 ft. Is that my span (6-7) or is 14 ft. my actual span?

My original plans was to sister joist 2X6s and to cover with 3/4 tongue and grooved flooring. Unfortunately, looking over large areas of the attic it appears that wiring may greatly affect the support of the sisterig effort.

I am looking for Ideas to make this work out. Suggestions....Please help!

Thanks,
Chris
 

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Why not just sister 2x10 or 2x12 up there. If you just want to go with the 2x10 or 2x12 for floor joists, and redo the roof to allow for even more space up there, you are going to have to get plans drawn up along with pulling permits.

If it was me, I would just sister the 2x10 or 2x12, so you get more space for under floor duct work, etc.. Can you post a floor plan of what the building foot print looks like, and the current floor layout, and future layout with what you are wanting to do with that space.
 

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Discussion Starter · #3 ·
Clarification....

All,
I am not following how a 2X10 or 2X12 would help things....please elaborate more on the advantages over my existing 2X6 sistering....

With this in mind...I may need to rephrase or clarify the issue. Basically 1/4 of my house was gutted down to the concrete exterior walls. All drywall, electric, phone, communication, even the elabroate stone fireplace was redone. The ceiling rafters of 1/4 of the house were sister joisted with 2X6. Then new wiring etc was installed followed by insulation, drywall, etc.

My plan was to do the remaining of the attic by sister joisting as well. What I have found is the first few rafters contain a considerable number of wires to deal with (6 - 12/2, 1 -RG6, 4 cat 5e, 2-8 wire phone cable). Most are in the center of the rafter and they of course are not all grouped together. Unfortunately, I will not be able to cut out/trim around these wires and place the rafter in place as it takes a consider amount of the support out of the rafter. I also believe removing the wires and placing the rafters, similar to what we did in the living room would be a considerable effort considering the number wires involved.

I am looking for suggestions/products/methods, keeping in mind that my span is 14ft (max). and this is a cape cod attic to reinforce the floor to support bedroom activity (~30 lbs/ft2). I am also looking to see how the joist span ratings apply if there is a wall tied in the middle of the span lumber.

Thanks,
Chris
 

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All,
I am not following how a 2X10 or 2X12 would help things....please elaborate more on the advantages over my existing 2X6 sistering....

With this in mind...I may need to rephrase or clarify the issue. Basically 1/4 of my house was gutted down to the concrete exterior walls. All drywall, electric, phone, communication, even the elabroate stone fireplace was redone. The ceiling rafters of 1/4 of the house were sister joisted with 2X6. Then new wiring etc was installed followed by insulation, drywall, etc.

My plan was to do the remaining of the attic by sister joisting as well. What I have found is the first few rafters contain a considerable number of wires to deal with (6 - 12/2, 1 -RG6, 4 cat 5e, 2-8 wire phone cable). Most are in the center of the rafter and they of course are not all grouped together. Unfortunately, I will not be able to cut out/trim around these wires and place the rafter in place as it takes a consider amount of the support out of the rafter. I also believe removing the wires and placing the rafters, similar to what we did in the living room would be a considerable effort considering the number wires involved.

I am looking for suggestions/products/methods, keeping in mind that my span is 14ft (max). and this is a cape cod attic to reinforce the floor to support bedroom activity (~30 lbs/ft2). I am also looking to see how the joist span ratings apply if there is a wall tied in the middle of the span lumber.

Thanks,
Chris
It's very simple....the wires come out....joists go in....then you drill new holes and put the wires back. That's how its always done ....the right way. You have to put the new joists in....so the wires come out. No way around it. Sure its work....but that's what you have to do when sistering joists...
 

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What is there not to follow SolomonMan. A 14 foot span is too far to support any kind of weight with 2x6 joists, even if they are sistered. You want to do the upper floor properly, have an architect file plans, then file the proper permits with your building permit department. If they do not like what they will see, they will not issue a permit, and require you to have them redone.

At 14 feet, you are going to need a min. 2x10 floor joist. 2x12 is better, because it gives you more room as I stated before, to allow the proper duct runs and plumbing if needed, so you are not cramming the mechanical's in between the ceiling of the floor below, and the sub-floor of the room you are creating.
 

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As said, you will need a S.E. to calculate the loads. Spans are from inside edge of bearing wall to another inside edge, not total lengths. A doubled 2x6 (fb. 1500#, #2) will support 64# per square foot w. 14' span (1/360), divided by the on-center spacing. Additional roof loads will reduce the total loads, be sure to have it professionally sized as said. Do not notch (top or bottom) ANY joists!

Gary
 
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