How to change floor joists from 12 to 14 inches

[jryan15]

Hi all,

 

I have a complete and framed floor plan for a 3BD ranch with a finished basement.  I would like to change the floor joists in the basement from 2-1/2x11-7/8 to 3-1/2x14.  To accommodate the reduced height in the basement, I would like for the basement to get a little deeper.  I would prefer not to have to redo the already completed floor plans and walls if possible.

 

Any guidance would be greatly appreciated.  Thanks!

[y-g-m-n]

 I would think you would go to:

DEFAULT SETTINGS under EDIT tab

Then Select FRAMING and click EDIT.

 

And set what ever you want for foundation, 1st, 2nd and I guess 3+ floors if you have them.

 

Walls should not move but since you are adding 2" everything gets taller.

 

PS normal flloor joists are 2x12 nominal (1.5"x11.25" Actual)

 

you list 2.5"x11.875" guess that is some sort of fabricated wood beam or glue lam etc??

 

3.5"x14" has tobe glue lam and to use those for floor joists will get real expensive.

 

Also what is under these "BASEMENT" Floor joists as I always though you had a concrete slab poured in basement sitting on some drainage stones packed inside the foundation?

 

What amI missing?

 

Maybe some screen shots of wall cross section showing floor and ceilings would be helpful

[Rookie65]

Some of the ability to change the joists may depend on which version of the program you are using. Last I knew, I think HD Pro was the only version where you could change the framing defaults.

[jryan15]

Thanks for the tips, I think setting this in the defaults will work out.  For the joist size, the 40 series I-joists at Menards are 2-1/2 x 11-7/8" where as the 65 series I-joists can be 3-1/2 x 14".  Both of these I-joists appear to be cheaper than a regular 2x12 at least when I compare at 24'.

[y-g-m-n]

24ft is a long span for that depth material..

make sure you read the engineering specs/docs to know max span based on floor load per sq ft based on Center to Center distance and free span.

Another note is I-joists tend to need blocking between flanges at ends where they rest on walls to prevent web buckling.

 

your local building codes should state floor loading based on what it is; attic floor, home living area, Commercial office space, etc.