Building An Addition, Got a Framing Question...

[TPI Monte SS]

OK, my head is spinning here - as you can see, I posted this at 2:30 AM cause I can't sleep! I need some advice from the construction experts. My wife and I have decided we're going to build an addition onto our house, and we're doing a majority of the work ourselves or with people my father-in-law worked with. He's been a mason for 50 years and used to build houses in Italy, so he's got a lot of skill.



We're adding a 12' wide x 14' long dining area off the back of our kitchen, and then adding a bedroom above it on the 2nd floor. Now, we'd like to cantilever the 2nd floor room 2' on each side, making the bedroom 16' wide x 14' long. Our architect says 2x10 floor joists at 16" apart will be fine, but my father-in-law thinks we need 2x12s. Who's right?

[Fireeater]

Personally, I would use TGI's on the second floor. It may cost you a little more money, but in the long run, it will be worth it. Look into those. Saves you some time also by not having to look at each 2x10 or 2x12 to figure out what side has the crown.

Dave

[jasonsnova]

call the local building inspector.....codes vary area to area !

[GRNOVA]

I agree call building inspector and find out the construction codes in the area.

[scogin918]

We sell TJI's (Truss Joists) and the most common size is a 12".

I just talked to my Engineered Wood guy and he said 2' is the most you can cantilever and you need blocking in between the joists where they pass over the lower wall. For us 12" Tj's(actually 11-7/8") are cheaper because we stock them as do most yards.

[scogin918]

call the local building inspector.....codes vary area to area !

So do building inspectors.

[gordonquixote]

As noted above, this is a code issue. The 2' overhang is kinda irrelevant - the joist size and spacing is what matters.

[amx2334]

If your doing the work yourself the tj's will be alot easier to handle also. Your back will thank you.

[twosaturns]

even if codes allow for 10", I would go for the 12" TJI. you won't regret an overbuild, but underbuilt sucks.

[Paul_J]

You're near the limit of the 2X10 without the overhang. Use a 2X12 at a minimum and get some sleep.

[Fireeater]

What did you decide to go with?

[TPI Monte SS]

Well, we're waiting for the next round of design/blueprints from the architect to see where we're at. But it's funny, after I posted this thread, I looked at the joists for my 1st floor from the basement. My house is just over 24' long, and has 2x10 floor joists that run that length spaced every 16". Our house was built right around 1939, so it's just about 70 years old. Our first floor doesn't creak, and we've had a heavy mud-job ceramic tile floor on top of more than half of it for the last 6 years. But, the house is straight up so the weight is more evenly distributed. Since we're planning a 2' overhang for each side it may really stress a 2x10. I looked up the TJIs that scogin and twosaturns recommended, and they look like great pieces. I also like natural lumber, as does my father-in-law. We see these new houses going up with the engineered/glued wood, and I'd be leary of using something like that. Like I said, my house has been here for 70 years, and I hope it'll last at least another 70. That would make me 105 years old.

[6fastback7]

Its hard to compare the lumber from back in the 1940s when that house was originally built...for one take a measuring tape and you will see those beams are most likely larger or close to being 2x10s...compare that to the diameter of lumber you get today of the same dimensions. And where i live we use to have plenty of Fir wood that we used in construction...that stuff is tough as nails..it barely warped..and you could barely drive a nail in it once it aged. Now we use crappy Spruce wood...which is prone to warping is smaller in diameter and not even close to being as strong. I have a 1960s built house that is completely Fir wood construction...its solid as heck...i wouldnt even begin to compare the framing of this house to even a custom built house built today.
So my opinion is ...dont stick to minimum code! use a 2x12 and you wont have to ever worry about issues with the framing in the future. For the price difference its not worth worrying over..invest the extra money in structure!

[romar 02 SS]

If your unhappy with 2x10 use 2x12. The architect should know the correct sizing of the floor joist and the local codes, if he doesn't then find another architect. Also the city should have reviewed the plans and ok'd the drawings. It never hurts to overbuild if you can afford it.
Larry

[Bill Howell]

2x10 is plenty for 12' span
Even if you use 16' you are fine since you are breaking them at 2' and 14 foot.