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Head Grunt
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Discussion Starter · #1 ·
Never worked with i-joists much so i have a question pertaining to squash blocks. Quick scenerio of the job 1st. Building is 40'X60' on piers next to a lake, fella buys the place and has a contractor assess the structure and then remodel the inside. The building was originally a dance hall from what i have been told. There are 20 piers total, 16" wide and 32" long, 5 piers to the long of the building and 4 to the wide, average 10'-12' apart depending on direction. Sills are tripled 2"X8"s all the way around and there were 3 main beams running the long way on the piers of tripled 2"X8"s. The rest of the joists were 2"X8" every 16" on center. The contractor came in, stripped the walls, rewired and plumbed. They put new 20' 2"X6" floor joists 16" on center right over the old floor centered on the old joists, filled them with 2" aluminum faced foam and then sheeted with 5/8ths plywood. The walls were padded out with 2"X4"s and insulated, drywalled and painted. All new windows and doors installed, new kitchen cabinets, appliances, showers, sinks, furnace, etc. House wall done except carpet, final attachment of plumbing to well and septic and propane lines. What happened???? The old floor joists started to break and some collapsed.

So, now i have taken the job on to tear out the old and new floor joists and i have chosen to fabricate a new center beam using PT 2"X12" with 2"X4" on top of that with 3/4" PT plywood in between, the lumber being tripled and plywood in between glued, nailed and screwed and a 2"X6" pad underneath for more height. I have begun raising the building up and padding under the sill another 2"X6" also. When the previous contractor started his new walls he put in a new 2X6 sill against the existing wall and framed upward from that. So now i am padding out the old sill with PT 3/4" plywood and PT 2"X10"s to catch their 2x6 sill and support the new walls better. This gives me 16.5 inches now from the bottom of the old sheathing which i cut flush to the drywall and to the top of the pier. I am now installing 20' long 16" tall i-joists to go from my new main beam to the old/new sills. This gives me 1/2" off the piers which are also all covered with 1/2" PT plywood as i go and the top of the i-joist comes right to the bottom of the old sheathing that i have cut off.

Now after writing this book i would like to know if i should be installing crush blocks as i no longer have a load bearing wall on the ends like i normally would have? Also so should i install crush blocks where some of the interior walls do set on the i joists as the do have some load on them? The way i have done this i will be resheathing the floor with 5/8ths advantech to match what they have so much of the load will redistributed. The joist hangers i have do not offer room for 2"X wood. The flange is only 2.5" so i can only use 1" or smaller blocks. I was thinking of using 5/4"X6" PT decking for blocks if i need them. Also the joist hangers are not predrilled for blocking either, what would be the best way to attach the blocks then? I was thinking of glueing them and then screwing them together sandwhiching the i-joist.

I can show pics of what i have done thus far so you have a better idea.
 

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Head Grunt
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Discussion Starter · #4 ·
Thanks, i am going to my supplier today anyway so i will ask while i am there. I am picking up some of the sheathing today so i can start sheathing the floor so we have some walk area and a place to put more materials out of the weather "snow coming". I would rather put the blocks in now if needed then be crawling around in the dirt and in the dark trying to put them in later.
 

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My rule of thumb is
1.Under any point loads.
2.Under any load bearing walls.

Exterior walls generally don't need them (excepting point loads) because the rim joist is there to resist the compression.
 

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Head Grunt
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Discussion Starter · #7 ·
It seems to me that you're combining squash blocks and web stiffeners. Check out the TJI framing guide: http://www.woodbywy.com/downloads/9030.pdf . A couple of pages in there show the two side by side.

Never seen ply squash blocks - only dimensional or engineered rim board.
Thanks for that info, my supplier actually had nothing for info and was calling in to their supplier for the info. Yes, it appears i was misunderstanding web stiffeners with squash blocks when referring to the ends of the i-joists in their hangers. From the reading i do not need the stiffeners on the ends but i will be installing stiffeners on the sides where i have walls sitting on them for the extra support.
 

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Is there some reason that you didn't use an LVL or an engineered center beam, cost, availability, couldn't fit it due to existing structure, size not right. Just curious as to using the built up beam with all it's components? It seemed like a lot of work to assemble the center beam if an option was feasible to use a single piece, it might have just weighed a ton and been impractical to install it. Just wondering.
 

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Head Grunt
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Discussion Starter · #10 ·
Is there some reason that you didn't use an LVL or an engineered center beam, cost, availability, couldn't fit it due to existing structure, size not right. Just curious as to using the built up beam with all it's components? It seemed like a lot of work to assemble the center beam if an option was feasible to use a single piece, it might have just weighed a ton and been impractical to install it. Just wondering.
Actually i ordered LVL's for the center beam which the HO was ok with but then backed out and requested i build one out of PT. I assured him they were somewhat moisture proof and i was covering all the piers with 1/2 PT plywood so they would not be making contact with any concrete but he still refused. Now i am stuck with the LVL's, luckily i can use them on my own home.
 

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Woodchuck... As everyone suggested, when working with TJ's, there is some specific MI and eng considerations with those... and pretty smart to review them.

They are an engineered system.... web stiffners have specific requirements, as do squash blocking.

I could not really understand your application,.... but the MI on joists is relatively simple/understandable.... seems to me to get more complicated with rafters.

I love them... but everytime I encounter their use, it just takes 20 minutes to understand the application assembly.

Best
 

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Head Grunt
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Discussion Starter · #13 · (Edited)
Is there a permit on this or you just winging it?
HO pulled permits for this, house has been under permit since 2007
HO is also an insulation contractor himself. He is in kind of a pickle with this home. He spent big bucks for the property for its 200+ ft of lake frontage, 4 place tennis court and this building. He spent big dollars in having the building remodeled only to have the floors collapse under it. So, does he have me rip out the floors and joists, replace with new and better, raise the home up another 2' and then build new enterance way and lake front deck or call it a loss, tear it down and go through the hassle with Town, County and State agencies to build a new home? We all know being so close to the lake he would have to relocate the home, deal with wet land issues, replace the septic to new specs which is already new but never used and is now grandfathered in and go through who knows how many other regulations? Mind you, when this is finished it will be just a seasonal rental so he can recoupe some of his money lost already.
 

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Head Grunt
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3,270 Posts
Discussion Starter · #14 ·
Is there some reason that you didn't use an LVL or an engineered center beam, cost, availability, couldn't fit it due to existing structure, size not right. Just curious as to using the built up beam with all it's components? It seemed like a lot of work to assemble the center beam if an option was feasible to use a single piece, it might have just weighed a ton and been impractical to install it. Just wondering.
I could not use a one piece beam either. I am doing the home in sections so i am adding to the beam as i go. Kind of a PITA as i have to be sure i keep all joints staggered for strength and keep it straight and true as i glue/screw it together. IMO it is just about impossible to remove all the floors and keep all the walls suspended on jacks so a new one piece beam could be slid under and jacked up to pier height and slid in place. I am already finding the walls trying to kickout as i raise the sill for padding and shimming. I feel if i try to raise the whole building with no floors at all the walls will give outward under the load.
 
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