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Is weight a problem when putting sub floor over old subfloor for bounce fixing?

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  #1  
Old 02-05-17, 06:16 AM
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Is weight a problem when putting sub floor over old subfloor for bounce fixing?

The room is 16 Feet by 11 feet the house is from the late 1800's so it is full dimension 2x6x16 inch floor joists and there is a good spring to it.

I was just going to take 3/4 inch plywood and screw/glue it down over the original planks to get rid of the bound and strengthen the floor. Should I be worried about the weight of doing this?

My wife would prefer I pull up all the old pine planks and add cross bracing them put down the 3/4 plywood.

I cant imagine there is a huge weight difference in the 2 methods.

What should I do?
 
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  #2  
Old 02-05-17, 06:38 AM
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Welcome to the forums! Have you checked the unsupported span of the floor joists all the way across the house? Often installing piers and wedging them tight will help with bounce. Adding subflooring won't necessarily stop it, but may be necessary to install certain floors like tile.

If you do decide (after checking the span) to install plywood over the planks, do not glue it down, and do not hit the joists with your decking screws. If you do as your wife says, you will be installing two layers of 3.4" Advantech rather than one as 3/4" is barely sustainable for a subfloor. 1 1/4" is ideal. I would also screw my planks down to the joists prior to installing your Advantech or plywood. It will help keep squeaks down.

Edit: I didn't answer your question. With proper support as the piers will afford, the weight won't be a problem.
 
  #3  
Old 02-05-17, 06:50 AM
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It will be 16 feet unsupported. The Master bedroom has the same foot print and the living room which is directly below it and there is no support beams or anything in the living room.

Trying to figure out the most cost effective way to take the bounce out of the floor.

Sistering seems difficult, unless I can use less than a 16 foot 2x6 because I dont see getting such a long board in the house.
 
  #4  
Old 02-05-17, 06:55 AM
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Are you saying you have 2x6 spread out 16' on a second story without central support?
 
  #5  
Old 02-05-17, 06:57 AM
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What's under that floor?
Crawl space, basement, another room?
If it was mine I'd be adding a center beam made of doubled up 2 X 6's with new footings to split up the span, 100% sure way to spot the bounce and lift the sag out of the middle of the room caused from the undersized floor joist.
 
  #6  
Old 02-05-17, 06:58 AM
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The Room is 11 feet by 16 feet. There is a support wall where under all edges of the room.
 
  #7  
Old 02-05-17, 07:01 AM
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Living room is under the bedroom
 
  #8  
Old 02-05-17, 07:02 AM
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Daniel. Is this a second floor room without support under it? Of course the walls give support, but a 2x6 cannot span 16 feet. Is there any central support?
 
  #9  
Old 02-05-17, 07:05 AM
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No there is no support in the center of my living room, holding up my bedroom.
 
  #10  
Old 02-05-17, 07:06 AM
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I've got to agree with joe... if your floor joists are 2x6 and they span 16', adding more subfloor is not the answer... crossbracing is not the answer... only adding a beam under the joists at 8' will stiffen that floor.
 
  #11  
Old 02-05-17, 07:10 AM
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Adding a beam, is impossible as you can probably tell. So we may just have to live the with the bouncy floor....Considering the house is in the neighborhood of 140 years old I double the floor is going any where.
 
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Old 02-05-17, 07:12 AM
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Why is adding a beam not possible? It is done every day.
 
  #13  
Old 02-05-17, 07:19 AM
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Do you mean adding a structural post coming out of the center of my living room? Or a engineered beam spanning the 16 foot length. Both are impractical considering my living room doesnt need a remodel. I can gain access to the floor joists from above if I remove the original subfloor.
 
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Old 02-05-17, 07:25 AM
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No, you can use either a single or double LVL in 11 1/2", supported on either end to the floor and then beyond to the ground with proper footing. The support will need to be a dimension of no less than 3", so 4x4 or doubled 2x4's will need to be attached. Can you post pictures of the walls perpendicular to the joists? http://www.doityourself.com/forum/el...your-post.html
 
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Old 02-05-17, 07:38 AM
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Beams are horizontal. Posts or columns are vertical. You need a beam under that floor, the posts that hold each end would be concealed in the living room walls, with the post load finding it's way down to a footing, foundation, or another suitable load bearing beam.
 
  #16  
Old 02-05-17, 07:40 AM
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Without moving a bunch of stuff these are the best pictures I can get. Included 2 picture from below.
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Last edited by chandler; 02-05-17 at 07:52 AM. Reason: space pictures
  #17  
Old 02-05-17, 07:55 AM
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OK, the below pictures are what we are looking for. What we are looking for is a place to put a post in order to hold up your beam. So far not nice. You have an opening and a door positioned just where the post needs to go.
 
  #18  
Old 02-05-17, 08:07 AM
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And obviously sistering all the 2x6 joists will do nothing to help the structure of the room?
 
  #19  
Old 02-05-17, 11:38 AM
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I rememberd that there was a small patch in the floor that I can pull up. I was able to measure the floor joists and they are 2x6.5 inch rough cut.
 
  #20  
Old 02-05-17, 11:42 AM
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I would expect you should locate one column at the base of the stairs... beam would sit on that (with support below column to foundation) other end is ??? Can't get any sense of direction from those pictures. But it would create another cased opening just like the one in the middle photo, just 8' away at the bottom of the stairs.
 
  #21  
Old 02-05-17, 11:55 AM
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If you sistered each one with a 7 1/4" 2.0E Microlam LVL you might be able to have a solid floor. Or 3.5x6.5's... it would be quite expensive, and they would need to be brought in through an upstairs window with a lift. And they still would probably be slightly overspanned if you went strictly by their span tables.
 
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