2x8 floor joist?

Started by CjAl, June 16, 2012, 06:08:35 PM

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i am wondering if i would be making a mistake using 2x8 on 16" centers for my floor joists. they will be spanning 9' 1.5". it meets the span table requirements i looked up. #3 is rated for 9'6", #2 is 12'something.

i was planning to use 2x12 but i am thinking i would like to use pressure treated but i would need to use a smaller joist to be able to afford it.  im not sure what grade is used for p.t. but it has to be better then #3 isnt it? 

even though it meets minimum requirements i just wonder if i will find it too springy. i run about 350lbs and i hate a springy . yaya i know, diet.

alex trent

Seems to me that if the table says 12 feet and you have 9'6" that is plenty good. I bet you can find out what the grade of the PT wood is where you buy it.  I bet it likely is #2.

I do not think this is early "minimum requirements"...you have 30% less than the allowed span.

If I could do one or the other, I would use PT and 2x8


ya i need to find out the grade of pt at lowes. i am sure its 2 at least but i like to assume the worst at #3 and thats 9'6" with my span at 9'1.5", thats minimum. i am building the story and a half but i put a third beam down the center to add more footings and carry a ridge beam load

i have a parkers do it best lumber 4mi from my lot and lows about 20mi. i will have to check both when i get home. we have so many termites and ants i would really like to go PT. i have a 16' oak log i dropped to have cut into beams. i left one on the ground and withing a few months the ant hills and termits have just about covered it 


just looked it up. my local lowes carries #2 prime treated 2x8x10 $9.68. thats not too bad.

boy does the price jump from 2x10 to 2x12!! they are double in price. over $20 ea for 2x12x16. i need 18 of them for my beams. . . ouch. wish i could have used 2x10 for that. i could have got brackets for 6" rough cut and used 4 rows of 2x10 cheaper then 3 rows of 2x12 plus 3 sheets of plywood for filler


The word "prime" in the line "#2 prime treated 2x8x10 $9.68" means nothing. It's #2 and that is the usual. I don't think I've ever seen something labeled #3.

Look at the oak log as being "bait" for the termites. Leave something like that laying around and when they go for it poison them.  Commercial bait type termite products do just that... a series of stations around the building perimeter with plain wood bait sticks. Inspect once a month or so and then drop in the poison sticks when the stations show activity.
Just because something has been done and has not failed, doesn't mean it is good design.


our lot was cleared with a mulching machine just before we bought it so right now there is LOTS of decaying roots to be eaten. i am hoping the termites taper off a bit eventually