Spanning 20' with 2x10s

[tngunlvr]

I want to finish off my attic over the garage. The floor joists are 2x10s 12" OC . This room is going to be a bedroom. I looked at some span tables and the 2x10s 12" OC only span around 18'. Right now the floor is pretty bouncy.What can I do to span the 20' and meet code?

[Ed Imeduc]

Id call and ask code there where you are . Then you will have it right.

ED ;)

[awesomedell]

I agree with Ed, there are specific national codes in effect in most locations in the country for occupied area of a home also failure to do this right could come back to haunt you down the road should you ever wish to sell the home. Your local building inspector's office is a good place to start. Here's a link that may also be helpful.

http://www.mcvicker.com/resguide/page013.htm

[ttmon12]

According to International Residential Code 2003 , #1 Douglas Fur joists can span 21' with 2x10s at 12"oc for sleeping areas with 10psf live load (30 psf dead load).

[Joe.Carrick]

Be careful!

#1 Douglas Fir is not normal. Most joists are #2 Douglas Fir. I would doubt that your home has #1 DF joists.

Also, I think the UBC and BOCA both require a design live load of 40 psf for living spaces plus at least 15 psf for dead load.

The chances are that you would need at least 2x12's @ 12" o.c. That's what we used in our living room (20 ft span) when we built in 1991 (Southern California) and I would not use anything less.

[ttmon12]

Be careful!

#1 Douglas Fir is not normal. Most joists are #2 Douglas Fir. I would doubt that your home has #1 DF joists.

Also, I think the UBC and BOCA both require a design live load of 40 psf for living spaces plus at least 15 psf for dead load.

The chances are that you would need at least 2x12's @ 12" o.c. That's what we used in our living room (20 ft span) when we built in 1991 (Southern California) and I would not use anything less.

I agree. Just answering a silly question with an absurd answer. The floor is bouncy and does not meet code (I assume #2 Hem-Fir) for a bedroom.The thing to do with the 2 x 10s is get rid of them.

[jatco]

How about a Lam?

[Joe.Carrick]

I assume you are referring to micro-lam joists. Generally, they provide better structural support. However, it's unlikely that a 10" microlam would solve this problem. Basically the problem is deflection ( and bounciness ) and in that regard there would be little if any difference.

[jatco]

The lam I had in mind is one similar to the couple used on this house I was helping frame. It was 10" thick x 6"wide-something like 24' long and weighed a 'ton'...or felt like a ton. Being used on a 3story home floor joist.

[Joe.Carrick]

That would be used as a beam to support the floor joists and would not run in the same direction. tngunlvr was asking about the floor joists which are spaced only 12" apart. It would be possible to put in a beam under the joists but it would probably not be easy and it would require footings of sufficient size to support the point loads at the ends of the beam. That kind of fix is not normal for this kind of project as it would be quite expensive.

[jatco]

Right.. gotcha!