Kitchen Floor Joists and screws issue....
 

Hello,I am a weekend warrior that can't sleep (mod edit) at night because of something I did. I am getting a new floor installed (Porcelain tile) and decided to screw down the existing 3/4 subfloor really good by using 3 inch screws. I since have learned that this was way too big and that 2 inch screws would have been ideal. My question is did I ruin the joist's integrety now? They are 2X10s that are all sistered together. I only screwed down one side of the sistered joists but I now believe that I may have weakened the floor system to support the tile. Is it safe to procede with the tile installation?The floor appears to be very stiff when I jump up and down and no bouncing occurs, but I am sick to my stomach since I cant revearse the screw size obviously....Please help.

Hi and welcome to the forum.

Go back to bed and sleep well, you did nothing but a little overkill and did not harm the 2x10s one bit, I'm sure.

DM

Biggest way to ruin integrty of the joist is via notching it incorrectly or boring holes through it incorrectly. Screwing into it from the top with a 3" inch screw wouldn't weaken the joist.

Now, if you missed the joist and the 3" screw hit the gas/water line then you got issues.

no worries, enjoy your new floor.

thanks for the replies, but some details...
 

Thanks for the responces and the good news. There are no notches at the top or bottom (or holes cut out).

I dont want to sound like a worried sole about this, but there are people (local lumber yard included) that told me anything bigger than a 2 inch screw removes too much wood and weakens the joists. You guys are saying that I just paid a little more for fasteners and went overkill.
So, there should be no issues then to have a mud base added and porcelain tiles installed. Correct?

You should be good to go.

unless your 'screws' were 3/4" bolt head lag screws, I wouldn't worry about the joists below. *grin*

DM

I would take the advice of DM anyday over the advice from a lumber yard. Your floor isn't any weaker because of the screws.

Now the next question you need to ask: Is your floor (joist and subfloor) stiff enough for tile? That is a question you should ask in the tiling section. Be prepared to provided the floor joist sizes, species of lumber, floor joist spans, on many inches on center, thickness of subfloor and proposed tiling (CBU, Ditra, etc).

wood species...
 

I believe I have #1 doug fir spaced 16 OC (sistered as I mentioned). The span is about 14.5 feet.The actual size of the wood is 9 inches deep so maybe that affects the stiffness for tile. My builder blocked the joists as well which should help stiffen things up right?
I know that some 2X10 joists are closer to 9.5 inches. Wonder why that varies.

what's underneath this floor? crawl space? basement?

DM

full basement
 

We have a full 8 foot basement. It's a finished basement with sheetrock on the ceiling (where the kitchen is above). I guess that is added what to the joists as well. I was actually thinking about adding an i-beam or something like that until now after hearing you guys out. That wouldnt have been cheap so beers on me. hehe:thumbup:

:laughing::laughing::laughing::laughing::laughing:

Sorry, you may want to avoid getting any info from these sources.

BTW..... where are we meeting for beers? If you toss in some chicken wings, I will give you the real scoop.

Kevin

lumber yard
 

I cant tell you how depressed I was after speaking to the local lumber yard. They shouldnt let people speak who dont have any clue what they are saying. My house means everything to me. I still wish I would have checked into a site like this to find out more details on what fasteners to use. You could say I will be checking into this site often.

BTW: Beer and wings sure do go great together.

first off, screws move the wood... but they do not REmove it....
that should have been your first clue..... I'm surprised that a lumber yard would tell you that....

DM

Take it from this building inspector...You did your joists no harm! :no:

The best way to approach the typical lumber yard, box store or hardware store is to only ask where an item is located. Before you even enter the store, make sure you have the necessary information to make an informed decision. Google and you tube will more often than not provide what you need as far as technical info. Forums are also a good resource.

The internet does a better job at revealing impartial data. It creates a more diverse and comprehensive source of info and strategy than that which the local stores offer.

Not to be a pessimist, but the future of some of these stores should include no persons just a computer terminal and a self check out. It would eradicate the foolishness of the uninformed guiding the uninformed. :whistling2:

Kevin

building code and construction...
 

"The building code is a minimum standard, and merely meeting it instead of exceeding it equates to building your project to the worst standard that the law will allow". :)

This is a great quote and reminds me of my solar panel installation I did 2 years ago. The inspector told me that my ground mounted system ( a glorified deck on a 35 degree pitch) was over built and unnecessary. He refered to such things as the stainless steel lag bolts that I used and the 3000 psi cement I purchased for the sonotubes at the base of the ground moint for 4X4 posts. Why be sarcastic about these these things. I happen to live at a high point on Long Island, NY and winds can get pretty strong in the winters here.