ICF Concrete & Rebar

[@hamdig390]

Thank you so much .. that is enormous amount of help !!!

[@teramusicofficial-musicfor6465]

Great information mate. Have a great day

[@Challenged1]

Thanks for watching!!!

[@AnN-py2em]

Thanks, great information. Hope to do my own someday.

[@Challenged1]

You can do it!

[@RobertHeron]

nice job!

[@Challenged1]

Thanks!

[@gregp4935]

Just saw your video. I am convinced that ICF are the way to go. Since I am also building in the Missouri area which is prone to tornadoes and probably won't have much luck building a basement for protection ICF would probably be my answer. What did you end up with height on your basement and your first floor?

[@CelBloxICF]

A high quality ICF block should be rated to withstand winds up to 250 mph. One trick to increase your wind resistance is to use spray foam in to insulate your attic. With this technique a wood truss roof can withstand up to 180mph. You set the floor and ceiling heights at just about any height you like.

[@Challenged1]

My basement came out to 8'8" and the main floor is 10' minimum with different vaults throughout Having that high of ceilings in the basement really doesn't make that area feel like a basement.

[@gregp4935]

I appreciate both replies. Next challenge would be to find a competent ICF Builder. Southwest Missouri is very hilly and Rocky so and ICF would give us security along with noise reduction and Energy Efficiency.

[@Challenged1]

@@gregp4935 That makes sense. I have family in the Kimberling City area on Tablerock that I visit every year. Even though I can't justify it, I've always thought building an ICF cabin on Tablerock would be pretty neat.

[@FelixRusu]

@Garrett Glaser I found your ICF videos very informative, even after 1 year of watching and reading everything i could find on this subject, thank you for sharing all this info, keep it coming! Don't you need to first install the joists and hangers to have a floor system above the basement to be able to start stacking the main floor blocks and then brace those walls, before the second pour? So you need to wait before installing that floor then another week or whatever it takes to stack the main floor, then repeat. With a 9-10ft basement wall, then another 10ft main floor (and optional 14-16ft for some areas such as Great Room walls), i assume its very hard or even a bad idea to attempt to pour such a tall wall in one go, although it would eliminate that cold joint.

[@Challenged1]

You are correct on all accounts.

[@CelBloxICF]

There is a much easier way to do your floor joists. Use and 8" block in the basement with a taper top block on your top course. Then switch to 6" block. This will leave you with a nice 4" ledge of concrete to just set your floor joists on.

[@Challenged1]

@@CelBloxICF This is a good idea. If a person does this method, they must know they need to use top chord load bearing trusses, otherwise they will have to build a bulkhead to hide the tapered portion of the upper wall. Also, they will most likely need to support the walls from the outside while building the walls (which is a real pain). Most icf bracing is 10' long, which usually is as tall or taller than most walls. You definitely want to have the bracing support that brickledge or else the block will want to rotate when filled with concrete since more weight is placed on one side. Another factor to consider is you will want to build your walls one course higher than the bricklege since basement pours need to stop in the middle of a course. You need to ensure that brickledge is completely full of concrete.

[@CelBloxICF]

@@Challenged1 Correct! This is a very well informed response! But you are referring to using a brickledge block rather than a taper top. The method your referring to is actually the strongest known way of constructing an ICF building. Many people even pour a 3" slab on top of their top chord bearing trusses. That's how strong it is! A taper top block has an internal taper and does not change the outer dimensions of the block. That's why you must switch to the smaller block size as you move up. It's not quite as strong as brickledge but it is much faster.

[@Challenged1]

@@CelBloxICF Ah, yes, I forgot about that style blocks. How much weight are the taper top blocks rated? Having such a small lip of engagement with the trusses, I would have some concerns.

[@shenoyglobal]

such a good information!... for a garage level and 2 more floors along with terrace on top with hollow core floors.. typically what is the rebar size recommended and is the wall thickness 12 inch recommended? i know this is a civil engineering question once the plans are generated but wanted to know your experience.. (this is in a miami dade county) high hurricane area and flood zone

[@Challenged1]

Totally location dependent and county code specific. I'm not well versed on the hurricane standards, so not much help

[@jaysondixon16]

How do you feel about using helix mixed into your concrete as a substitute for Rebar. I plan on building my home off the coast of SC so we do get hurricanes

[@Challenged1]

I would be comfortable using it for flatwork, but not walls subjected to lateral forces.

[@CelBloxICF]

CelBlox ICF is Miami-Dade Certified for Cat 5 hurricanes with just normal rebar.

[@jaysondixon16]

@@Challenged1 ok thanks

[@bkucinschi]

I wanted to ask Garrett the same question when I saw your comment. On Helixsteel.com they boast you can eliminate rebar by adding helix steel fingers to the mix, like 9 lbs/cy. Apparently there were some commercial applications where they did either reduce the amount of rebar or completely substitute it.

[@Challenged1]

@@bkucinschi In reference to ICF, keep in mind that the rebar actually helps keep the blocks in place prior to filling with concrete. Without it, the walls can tumble pretty easily with even a small wind. So I would say a person ought to use some rebar even if they are using helix just so the blocks survive until the day of the pour.

[@scottcraig1047]

How about using gfrp rebar? No. 4 can be purchased in 100 meter coils, so you could eliminate a lot of overlap splices vs. 20 ft straight pieces. The price of fiberglass rebar seems to be coming down, and is about the same as steel.

[@Challenged1]

Should work fine as long as your inspection agency allows it

[@sergeyc5528]

I saw some people using a runabout which basically is a pipe on the end of the hose that turns the flow of concrete 180 degrees before it exits the hose. Probably can make it yourself. What do you think about it?

[@Challenged1]

I was pretty much subject to whatever the pumper truck operator provided. The concrete comes out at such force, I'm not sure I would be able to control the hose with a 90 on the end. I just don't have any experience using one.

[@ppainterco]

@Challenged1 Any thoughts on using fiberglass rebar? I’ve read it makes a stronger wall and is lighter to handle. The con is you need to order bends for corners.

[@Challenged1]

I have no problem with it, but many jurisdictions don't allow it per code in place of steel

[@ppainterco]

@@Challenged1 I just looked at Menards prices, and another con of fiber glass is that 20’ lengths are about 2x the price of steel.

[@karenwilkey6512]

Have you compared fiber mesh concrete to using rebar? Would you consider one superior over the other? Know anyone who has used the mesh?

[@Challenged1]

I have not used it, so I can't say too much about it. The rebar helps hold the icf blocks in place and adds a ton of rigidity before the concrete is placed

[@davidgoodwin2500]

You use a #4 rebar throughout , was # 4 enough for the lintels

[@Challenged1]

Combo of 4's and 5's depending on the span

[@richardheinen1126]

How long after the first pour do you have to wait for the second pour? Around my area we talk in bags, 5 bag mix, 6 bag mix etc. what is the conversion from psi to bags? Oh and what do you think about fiberglass rebar?

[@CelBloxICF]

5 bag is comparable to 3000psi

[@Challenged1]

I would wait 7 days to place any sort of significant weight on the first pour. Normally, it takes a couple weeks to get everything ready for the 2nd pour factoring in cure time for the first pour (assuming we are saying the basement course is the first pour and the main floor is the 2nd pour). I don't know much about fiberglass rebar, but as long as the tensile and sheer strengths are equivalent to steel, then go for it. As far as the bag strength, that would be a question for your concrete supplier. I don't know the equivalents.

[@dustinabc]

How long between "lifts" would you recommend? (I'm guessing that might have been what was being asked here)

[@jb6044]

More pictures please, will help the entertainment value. :)

[@Challenged1]

Lost most of them due to a hard drive crash

[@JoeDuarteScientist]

A big reason to go for stronger concrete is to increase insulation at the same total wall thickness. Standard ICF blocks don't have enough insulation and use cheap Type II EPS, so being able to use a 4-inch concrete core instead of 6-inch would be a win, assuming you added two inches of insulation, either with yourl ICF vendor's official add-on pieces or standard continuous rigid foam boards (or mineral wool to have better fire resistance on that side of the wall). I don't like the culture of the construction industry when it comes to always doing the bare minimum. There's hardly any progress or innovation, very unlike almost any other sector. No one ever seems to want to build anything extraordinary or great. Using modern concrete would open up a lot of possibilities for the structure. For example, we don't actually need these crazy roofs with all these rafters and joists, certainly not *wood* rafters and so forth. We know how to build a lot better than that, with materials strong enough to support themselves. It would be cool to have a strong, thin concrete roof made of Ductal or EMC concrete. Fiberglass would be interesting too. We need to rethink roof design anyway if we want to knock down the cost of solar. If you used fly ash, I'd be surprised by a 3,500 psi result. I've never heard of fly ash resulting in such a low value. We can buy 5,000 and 6,000 psi mix at Home Depot, and I didn't think it used any fancy pozzolans. Like you said, the curing will be better than average in those forms, so I wonder if your true value is much higher than 3,500. I didn't know that we had to wait a week between levels. Why can't we just pour the whole wall and let it cure all together? I thought ICF would be super fast, like steel frame.