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# Dead Load on wood subfloor

#1
10-28-09, 06:47 AM
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Dead Load on wood subfloor

My house is 9 years old, I want to put a 500lbs safe in my walk-in closet on the second floor in the corner against 2 walls. One of the wall is a load bearing(outside) wall, the other is a partition wall and the safe would only straddle one joist running along the width of the safe. The safe foot print is 27"w x 23"d. I calculated the load at approximately 116 psf. Will my floor hold this safe up or should I turn it 90 degrees so it would be sitting on 2 joists but would only be against one wall?

Thanks;

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#2
10-28-09, 07:28 AM
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Hi Marty, not an engineer, but there are a couple of details that may help others answer.

The outside wall, are the joists running parallel or perpendicular to this wall. What I'm looking for is the length of the joist and position of the safe over that joist. Also, is the joist a 2x10 or 2x12 or an "I" joist. My experience is that even a 2x12 will sag over time if a weight such as a cast iron tub is placed in the middle of it. I can provide pictures if you would like .

One of the pros should be able to give you the dead load capacity, but you and I standing on that foot print should not fall through the floor.

Bud

#3
10-28-09, 08:02 AM
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The Joists are running perpindicular to the outside wall. I don't know the size of the joists.

#4
10-28-09, 08:25 AM
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If they are running perpendicular, then you are connected almost directly to the load bearing wall below. What is directly below this footprint?

Also, if the weight turns out to be ok, you could consider a metal plate under it to span the two joists and allow you to choose the preferred orientation.

Bud

#5
10-28-09, 10:52 AM
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The safe will be sitting directly on the subfloor(plywood), there is a carpet there now which I will remove from just under the safe. I am just wondering, does the subfloor run under the wall? If not, how is the edge of the plywood attached?

I will attemp to provide some drawings.

#6
10-28-09, 11:12 AM
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I am having a hard time posting a picture, how do I post a picture?

#7
10-28-09, 11:20 AM
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http://forum.doityourself.com/electr...your-post.html

Pretty complete instructions here.....

#8
10-28-09, 12:14 PM
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#9
10-28-09, 04:28 PM
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#10
10-28-09, 08:43 PM
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Floor joist loads are rated on;
1. the thickness and width of the wood;
2. the total span, from bearing to bearing;
3. the species of wood, a lumber stamp in ink on the side somewhere;
4. just a picture under the area from 6' away....
Be safe, Gary

#11
10-29-09, 12:53 PM
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I will try to getting into the floor tonight and take pictures.

#12
11-06-09, 05:11 PM
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My first inclination would be to say no, you should put the safe there. Especially on one joist. Most floors are rated for 40psf of live load and 10psf of dead load. The safe is only about 4.5 sq ft. and weighs 500lbs. 4.5 sq ft of @ 50lbs of required load (50x4.5ft.) = 225lbs. Of course running it across two joist would be better and close to the bearing will make a difference also. I am NOT an engineer, and you should consult someone who can run the calculations correctly.

#13
11-06-09, 05:33 PM
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Hi Door Guy, I was looking at those numbers and I must have the wrong idea as to what and where they apply. My 200 sq ft living room with 10 guests totaling 2,000 lbs would be more than twice that live limit. And at 10psf my wife will definitely have to toss some of her junk .

Is there a source of those numbers as they apply to different floors?

Bud

#14
11-07-09, 07:29 AM
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Hey...some of you might want to bookmark this Maximum Span Calculator for Joists & Rafters

Doesn't really calculate loads..but you might find it helpful in the future...

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