Load capacity on flooring?

[Sigarms]

Doing a quick search coming up with nothing. Does anyone have a direction they could send me in if I'm looking at what my max load capacity (lbs per sq foot) would be on my first floor (over basement)?

I'm looking at something that will be about 8 square feet, coming in about 180 lbs per square foot.

Don't think I'll have a problem, but would rather be safe than sorry.

Thanks

 

[kennyd]

Search the term "live load span" in Google. You will find charts like THESE.

 

[dmccarty]

Dang that is a heavy gun safe.

The tables are only going to help so much since they are designed to deal with the "normal" live loads in a house which is around 40 pounds per square foot. And it sounds like you might be dealing with more of a point load instead of the live load which is reflected in the tables.

If you want to play structural engineer here is a website with the equations. :laughing:

Structural Beam Bending Equations / Calculation Supported on Both Ends Loaded at any Location   - Engineers Edge

You might get a guestimate by looking at the joists under the Big Heavy Thing and figuring out how many of them will be carrying the load. The total weight would be spread over those joists. You should be able to get a real structural engineer for a few hundred dollars at the most to look at this and tell you if it is ok and if not, propose a solution.

Later,
Dan

 

[orezok]

Get 10 of your closest friends to come over and stand REAL close together. If you don't fall through the floor, you're OK. :laughing::laughing:

 

[Sigarms]

Search the term "live load span" in Google. You will find charts like THESE

Thanks for the link. I have some homework to do.

Dang that is a heavy gun safe.

Not as heavy as some of the other ones I was looking at:thumbsup:

If you want to play structural engineer

Not only no, but heck no. Math wasn't a forte of mine, but some would tell you I have common sense, something I've found that the PE's I deal with don't always have.

Get 10 of your closest friends to come over and stand REAL close together. If you don't fall through the floor, you're OK.

The question is how long would we have to stand there

How about "what's the heaviest gun safe you have on a first floor that hasn't gone through the floor?"

 

[2manyrocks]

Is your first floor framing open so you can see what kind of framing you have or is it all hidden from view? If it's open, that makes it easier to know what you have to make the calculations from the species/material span tables and also makes it easier to add more wood if needed.

 

[Sigarms]

If it's open, that makes it easier to know what you have to make the calculations from the species/material span tables and also makes it easier to add more wood if needed.

Open.

I'll be adding more wood no matter what.

I have no clue what I'm doing with wood, but my FIL does, and lucky for me I helped him out on his oil furnace

 

[/pine]

adding solid blocking between (perpendicular) the joists will help distribute the weight...

I would just double (or tripple) up the joists with 1/2 plywood flitch boards glued in between under the load..

 

[2manyrocks]

Are your basement walls framed 16" OC or are the joists sitting on a plate on a block wall to start with? You will want to get your framing done first as that weight is going to make it harder to install any reinforcement afterwards.

 

[dmccarty]

Since you won't play PE I will. :laughing:

You did not mention the span of the joists. A simple solution could just be adding a beam under the joists with the heavy load and putting a post(s) under said beam. Course the unsimple part is what the post(s) is resting on handle the weight and what size post(s) do you need? And should the post be metal and not wood. Which is cheaper? Will the post(s) be in the way in the basement?

A coworker years back was having a foundation and floor problem in a new house. He paid a couple hundred dollars max for a PE to look at the problem and provide a design for a fix. The fix was a 4x4 in the crawl space under the floor joists with a proper footer. In your case I would be concerned about a 4x4 working due to the height of the basement and/or you will need more than one. A metal post I would bet could handle the load cheaper than a few wood posts.

A load baring beam and post(s) could dramatically change the load capacity of the floor. But will it be enough? And which would be cheaper, beam/posts or beefing up the joists? Mr. PE would know and save time and effort. This really depends on the length of joist span, the joist size and where the load will be placed on the joists.

I bought the NDS, National Design Specification, years ago when designing our house. I AM DANGEROUS. But since I KNOW I am dangerous I used a PE to build our house.

Later,
Dan