Blocking Help

evolve · 11-11-2007, 05:38 PM

Hi All,

I posted this in the flooring forum but haven't had any responses to a couple of my questions. Hoping I might get a little better response over here.

I've ripped out the subfloor in my laundry room and half bath due to water damage. To put the new subfloor in I plan to add blocking to support it where I don't have an existing joist to work with (along the edge of the wall parallel to the joists). I'm working with 3/4" OSB and 11 7/8" I-Joists. Blocking with full height I-Joists is going to be difficult because there is a lot of plumbing to work around. My question is, is it sufficient to block only the flange of the I-Joist or should I be blocking with full 11 7/8" I-Joists? What is the proper way to do this?

Many thanks.

Ron6519 · 11-12-2007, 05:12 PM

You would need to install something akin to the vertical support the I-joists give. The minimal flange blocking would be inadequate for this application.
Ron

evolve · 11-12-2007, 08:41 PM

Thanks for the reply Ron. Sounds like I need to block the entire height of the I-Joist? Any tips for working around all the plumbing?

Check out the attached image. This is a small example of what I'm dealing with. I've got water hoses coming in for the washer and another one that heads off into the adjacent bathroom. There is also one, not shown, that goes outside to the sprinkler system. There are also electrical and coax cables to deal with but those should be simple to work around. The major thing in this case is the water hose running into the bathroom. It runs parallel with the joists. Any tips for dealing with this? Can I run it under the joist

This is really just a small example too. In the adjacent bathroom, where I need to replace subfloor as well, there is the toilet and sink plumbing to work around. On the other side of the room the main water line comes into the laundry room and then branches out to the washer, sink, toilet, hot water heater, outdoor faucet, etc. etc.

Anything I can do to keep from having to disconnect all the plumbing? Can I notch the edge of I-Joist? (probably not but thought I'd ask -- specs say no).

Thoughts appreciated, thanks!

evolve · 11-15-2007, 04:48 PM

Bump.

Anyone?

I had a contractor come out and look at it. He said he would just work around the plumbing as best as he could, use a jig saw to notch, and block the **** out of it. He also said that he'd use steel to reinforce it if need be. Any thoughts on this?

Thanks

Ron6519 · 11-15-2007, 05:31 PM

It looks like you could just connect the last two I joists together across the top, sort of like a ladder. Take 2x4's every 16" and insert them, vertically, in the web section. They'll sit proud of the 2x3 web top to give vertical support to the 2x3 ladder under the subfloor. You just go around the pipes inserting the 2x3 ladder where needed. That should give you enought support for the bath floor.
Ron

evolve · 11-15-2007, 10:53 PM

Something like this?

Ron6519 · 11-15-2007, 11:14 PM

The lower board would be vertical, against the OSB. The top 2x3 or 2x4 would rest on it, sort of like an inverted "U". The two vertical pieces would support the horizontal cross piece. You would install these inverted "U"s along the area needing support. The bottom part of the web(other 2x3) would support the vertical members.
Sorry, but I can't provide illustrations. A picture would be worth..., well you know.
Ron

evolve · 11-15-2007, 11:58 PM

Ahh, I think I understand what you are saying. Except I think I maybe missed the bottom piece.

evolve · 11-16-2007, 12:07 AM

Is it OK to be using solid lumber. I read that it's best not to mix I-Joists with solid lumber when blocking because they expand and contract differently.

Ron6519 · 11-16-2007, 11:39 AM

Quote:

Originally Posted by evolve

Is it OK to be using solid lumber. I read that it's best not to mix I-Joists with solid lumber when blocking because they expand and contract differently.

The difference would be the vertical "2x" material. Then use plywood built up in layers. I don't know what issues would arise using these few pieces of wood. I'm just a remodeling contractor, not an engineer.
Ron

evolve · 11-16-2007, 03:31 PM

Here's a couple of links regarding I-Joists and solid lumber.

http://www.apawood.org/pablog/index.cfm/2006/10/3/Help-Desk-Question-What-are-the-Risks-Involved-with-Mixing-Solid-Sawn-Lumber-and-Engineered-Wood
http://www.apa-europe.org/Languages/...ts/warning.php

47_47 · 11-16-2007, 03:53 PM

Not an engineer, just a woodworker. Lumber shrinks and expands along the thickness and width, not the length. I would use 2x material for the uprights and laminate plywood for the horizontal.