I have a very unique situation. I am remodeling my attic and we have a small section of attic that is only 6 feet tall at it's highest point, with slanted walls from that point on down. It is a 23 feet by 13 foot space though, so I didn't want to waste it seeing as we are turning our attic into a master bed/bath. We are going to use the space as a closet/ movie room, we already planned the whole thing, measured a couch that will fit and all.
I am going to have to re support the floor because they joists are 2 by 6's on 24 inch centers spanning 13 feet across and according to a floor chart I found, that won't cut it. I was going to add more 2 by 6s so that they would all be on 12 inch centers, and according to the chart, I would be golden in that case.
I bought the beams and cut one to size, started to put it into place, and it is too long, I can't get it in place. Cutting it any shorter would leave it unable to span the 13 feet so that won't work. I can't cut into the ceiling of the room underneath as I am not ready to redo those rooms yet. My question is, I need some kind of advice. Can I cut the beams in half, put them in place, and reconnect them using metal plates on either side or would that cause them to sag into the ceiling of the room below? Is there some other way I can re-support the floor (keeping in mind that I cannot get access to the ceiling in the rooms below this space)? Could I use a header in some way to help or would a herringbone strut help in anyway? Any advice would be great. I suppose if it just won't work out I will just chance it with the 2 X 6s on 24 inch centers, and deal with a bouncy floor.
I would question the ability of 2x6 joists set 12" OC to support a span of 13', but if your research goes with this then let's go with that to answer your question.
Here's what you do: Make each new joist mostly a double joist. Since you cannot fit a 13' long joist in there, measure out for what is the longest size that can fit. Let's say that 10' will work. Get two 10' long 2x6's. Install one tight up to the left side and the other tight up to the right. They will be 1-1/2" offset from each other. The outside 3' of each joist will be a single while the middle 7' will be a double (4x6). Nail the two together across that 7' overlapping length and you will now have a 13' long joist that is in place where it belongs.
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