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I have an 8" thick interior concrete foundation wall that I'd like to cut a 6.5" wide x 16" tall opening through. The wall is between an unfinished basement and a crawlspace and will be used to slide in an LVL beam to shore up joist deflection in the floor over the crawlspace. Will need to make two of these openings and was thinking of renting a rotary hammer drill and drilling a series of 1/2 holes around the perimeter and then chipping the rest out. Crazy idea or let a professional handle it?
 

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why not a supporting column OR steel bracket bolted to the wall instead ? a pro would likely use a diamond chain saw,,, you can also use a 14" blade on a demo saw but no, your idea's not crazy
 

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Ayuh,.... They're now rentin' those diamond blade chainsaws at my local equipment rental shops,.....
 

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Ayuh,.... They're now rentin' those diamond blade chainsaws at my local equipment rental shops,.....
My rental place does too....They make you buy the chain @ $250 and then rent the saw for another $225 and then +,+ and+ and your into it for over 500, in my zip code anyway.
 

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You can end up with a fairly clean looking hole if you first cut the profile with a diamond blade in a circular saw--then drill and chop----clean up the ragged edges with a diamond blade in your angle grinder---

Dust can be kept down if someone trickles water on the blade while cutting--plug into a GFCI outlet to keep from getting electrocuted.
 
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a diamond-segment chain for only $ 250 is cheap but its probably genl purpose segs ! gas saw ? the guys have noted several ways to do it - in atl, it would be $ 450 to hire a pro
 

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Discussion Starter #7
Thanks for the tips!

I do plan on using a bracket at the far end of the wall. The reason for the through hole and not a bracket on the one side is the weight and length of the beam. The inside dimensions of the wall are 16'4" and an LVL that is 5"x16" will weight about 315 lbs. Trying to get that into a bracket two brackets could be bear, especially when the crawlspace is 4' tall.

The midspan support is another option, but then again it'll require digging and pouring concrete footers. We do have a radon barrier and such in there, so would rather limit the time in the crawlspace.

One interesting tidbit I got from a basement company is they use preformed footers (2'x2' if I recall correctly) that are just set on the floor. I think they level the area somewhat and just set it on the ground. Seemed a bit fishy to me.

The chainsaw version sounds good, but does it do a plunge type cut? There is a joist and drywall on top of the wall so can't go from the top down.

Stadry, that was pretty much on the money from a pro to do it. We have a second crawlspace that could be made into a cellar, and for a few hundred more they would cut an opening into it. Good discount if they came and did both at the same time. But that's another project in a long line we have going on.

Thanks again for all the help!
 

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Thanks for the tips!

I do plan on using a bracket at the far end of the wall. The reason for the through hole and not a bracket on the one side is the weight and length of the beam. The inside dimensions of the wall are 16'4" and an LVL that is 5"x16" will weight about 315 lbs. Trying to get that into a bracket two brackets could be bear, especially when the crawlspace is 4' tall.

The midspan support is another option, but then again it'll require digging and pouring concrete footers. We do have a radon barrier and such in there, so would rather limit the time in the crawlspace.

One interesting tidbit I got from a basement company is they use preformed footers (2'x2' if I recall correctly) that are just set on the floor. I think they level the area somewhat and just set it on the ground. Seemed a bit fishy to me.

The chainsaw version sounds good, but does it do a plunge type cut? There is a joist and drywall on top of the wall so can't go from the top down.

Stadry, that was pretty much on the money from a pro to do it. We have a second crawlspace that could be made into a cellar, and for a few hundred more they would cut an opening into it. Good discount if they came and did both at the same time. But that's another project in a long line we have going on.

Thanks again for all the help!
Ayuh,.... For yer mid-span support, there's no reason not to clear, 'n level the hardpan there, 'n use a precast piece,...
I've use the round ones a few times, easier to get into place than a square piece,...
2' x 6",...

I stopped at the rental shop just down the road today, 'n asked 'em this question,...
They rent the big Stihl concrete saw for $140. a day,...
Ya pay $17. per .001" of chain wear,...
The Max wear fee is $500., as that's their cost for a New chain,...
Bein' a Contractor, he said they sell brand new $300. chains(aftermarket), that I could buy, 'n run on his saw, for the $140. per 8 hour day,...
1/2 day rate is available to Me, not sure otherwise,...

He did say, that cuttin' clear concrete it was reasonably efficient, money wise,...
'course, rebar cuts harder than concrete, so there's lotsa variables,...

It handles pretty much like a chainsaw, a plunge cut is always Tough to do, 'n kick-back is always a risk,...
You can start on a steep angle, 'n go to a plunge after ya got a pocket started,...
Start mid-cut, 'n work yer way up, 'n down,....
The bottom of the pocket might be a tough cut no matter how ya do it,...
Maybe score it both sides, 'n Wack it with a BFHammer,...:wink:
 

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Discussion Starter #9
Ayuh,.... For yer mid-span support, there's no reason not to clear, 'n level the hardpan there, 'n use a precast piece,...
I've use the round ones a few times, easier to get into place than a square piece,...
The leveling part I understand, but what would clearing entail?

From what my wife has told me (she bought the house years before we met or were married), there was dirt/fill in there initially, but gravel was added to get the slope right due to some water issues that have been resolved...

As for the precast pieces, any suggestions on suppliers or brands?
 

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didn't know there were ' brands ' for those - just be sure its got 2 mats of steel - 1 @ 90* to the other + 4" between them,,, if you get a 2' x 2', the rebar should only be 20" long so you get 2" of conc ' cover ' on all ends

as noted, plunge cuts are more dangerous tho not as much as wood
 

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The leveling part I understand, but what would clearing entail?

From what my wife has told me (she bought the house years before we met or were married), there was dirt/fill in there initially, but gravel was added to get the slope right due to some water issues that have been resolved...

As for the precast pieces, any suggestions on suppliers or brands?
Ayuh,.... Ya get 'em at the nearest concrete prefab plant you can find,....

Ya want the native soil, dug back to be flat, true, 'n level,...
Sit the pad directly on that,....
 

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Unfortunately I have no idea how far down the native soil is though. I could be digging 6 inches or 6 feet!

The reason for the beams are to shore up the joist deflection for bathroom floor tile. The bathroom is 5' wide x 12' long and the 12' section straddles the main beam of the house. The floor joists are 2x10's that span 14' and 14.5' to the front and back of the house. Based on deflection, best case scenario is one could be okay for tile, the other isn't. In case anyone is wondering, the issue with the deflection is that the joists sitting on the beam are going to act like a lever and put tremendous upwards force.
 

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That beam pocket does not need to be perfect---although a ragged looking cut will worry a future home buyer---

Always use steel shims under the beam----
 
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