Floor Joist 16" vs. 24"

[pioneergal]

What are the advantages or disadvantages.....if any.....placing the joists 16" or 24" apart?

Our plans are 48 X44 and DH thought of useing 2x10x16 as joist.
This would allow us to use 3 -16's across the 48'.

Will this plan work?

DH is setting the 6x6 sills 8' apart therefore the 16' joist would be supported every 8 '.
 

Learning as we go ...... before we spend the money.

Thanks in advance
 

Pioneergal

[pioneergal]

We checked on the prices of the 16's and doing the joist on 24" will save us about $500  over doing them on 16" acccording to the prices that we have today.

We want to save money where possible but more importantly we want to be structurely sound.

Once again, thanks!

Pioneergal

[John Raabe]

For a standard 40 psf live load (main floor) you should use DF #1 or Btr @ 16" o/c - #2 grade will not quite span 16'. Southern pine #1 or #2 will also work.

On my table there are no commonly available 2x10s that will span that floor @ 24" o/c

Also, when you go to 24" spacing you need to make sure the subfloor is rated for that span.

[pioneergal]

Thanks John for your reply.

DH and I admit that we are a novice at this building thing but we are eager and anxious to learn.

We want to do the project right even if it means spending more money now to do it right rather than have expensive repairs and regrets  in the future.

We are always open to suggestions.

Pioneergal

[PEG688]

 Hey Gal   Go to like page three  " Loft floor and roof framing "  good info on your joist spacing question and type of subfloor that will work . HTBH  ;)PEG

[n74tg]

I too would like to use floor joists or trusses on 24" centers.   Does anybody know what subfloor  materials work acceptably with joist spacings that large?

[jraabe]

You can call your local lumber yard to find subflooring ratings for the locally available materials. Tell them you want to span 24". Many 3/4" T&G products can do this when installed correctly. You can also go to 1-1/8" OSB or plywood for a rock solid subfloor.

[Amanda_931]

How dreadful the ³/₄ inch tongue and groove or the--ouch-- 1 ¹/₈ inch OSB (I've never seen that)  are to lift may play a part in your decision.

When I'm in shape the three-quarter stuff isn't too bad.

[hobbiest]

3/4 weighs about 85lbs a sheet.  Don't know about 5/4.  Installed a 3/4 osb TG floor on 1700 sq ft tract home yesterday.  24" OC joists, bit of flex, even with glue I wouldn't trust it.

[Amanda_931]

Would plywood work better?  

5/4 sheets of OSB are probably over 100lbs, but maybe not by much.  (would a 1/2 inch sheet weigh 15-20 pounds?)  The prospect of having to shove them around would make me think hard about 16" OC joists.  (they too could probably be smaller and lighter than wood spaced at 24")  

I've seen joists put in with 12" spacing--more thermal breaks, but it didn't matter much under the circumstances.

Particle board was a whole lot heavier.  And it broke every time you looked at it crosswise, swelled up permanently if it got wet. And back in the 70's it still got used as subfloor.  Because when it was dry it was so nice and smooth.

On the other hand the plywood at that time had an odd number of plies, almost certainly worked better that way.