The chairs are here. You can come up and check those out. We’ll show you the grid. This is the tie-wire system that Duane can talk to you guys more about afterwards if you all want to see how that works. But the bottom line is, that allows you to tie those vertical bars, splice them to the dowels and tie them to the horizontal bars. That little device down here, this is a snap-tie.
This is a pretty common thing used in standard concrete block work…poured concrete. We use it to attach our bracing positions. It’s typical. But as somebody asked earlier, you can use ICF bracing, you can use pole bracing if your mason has that and would like to use that, it works as well. Duane’s got the can of foam. This is the adhesive that holds it together. This is an EIFS adhesive. It comes out of this gun. And typically – we’ll lay a couple of block for you and then we’ll put a window up and I’ll talk to you a little bit more about what this is and we’ll show you the bond beams over the windows, the lintels, the headers, and that type of thing.
Okay, you want to lay some block? We’re not going to fully glue this one so we can get it apart more easily when we’re done. If you fully glue this, in about in the heat today, in about 10 minutes, you won’t be able to get them apart. Probably less than that, more like five minutes. Now, you can see the – the dimentional tolerances are really important with this type of product because you don’t have a mortar joint to make up any differences. You can use the spray foam to make up slight differences, but it just comes out of the can that quickly. So, on your horizontal, when do you pour the concrete or the grout in that horizontal joint between? You pour it all as soon as you stack this all the way up to the floor heigh.
So it’s going to flow not just vertically, but horizontally. It does. Yeah it goes back to that mix design, that 8-9 inch slump, and the vibration. And you’re only having to move 5 inches between cores. The core is separated by 10 inches edge to edge and you’ve got concrete flowing from both directions. You’ll pour the actual windowsills first, because you might have a longer distance for that to flow underneath. How tall do you build before you start pouring that? You’ll go a maximum of about 14 feet, and then you’re going to go ahead and pour that concrete. Then you’ll start pouring it in 4-6 foot lifts.
So your mason is going to keep the wall plumb level and straight while you’re stacking these blocks, and it utilizes that mason’s skill set already. They’re good at doing that, but he can double up on the number of helpers.
A normal masonry crew for laying CMU block is one mason and two helpers. On this type of system, they’ll do one mason and four helpers, because the guy can just bring block as quickly as he can. They’re following their string line that’s already in place, and the true mason, the really skilled labor, is reduced by quite a bit. Your aggregate labor rate goes down quite a bit, and you get that wall in quicker. So you put those rebar chairs there, he’s going to tie the bars to the chair.
I see you have a chain saw, but do you have a skill saw up there to cut it with? If you’re cutting through the narrow portions?
Typically we’ll use the electric chainsaw. It’s the best tool for cutting the meat out of the center of the block. Duane’s already made some lentils for over the window we’re going to put in here. And this is typically how we do it; we’ll cut out this meat to some degree, and then this we’ll fill with concrete. We’ll put more bars in here and we’ll put a little cage in there to give it more strength. Neel showed some good photos in his presentation. You’re building a concrete beam, so with this base block and the center cut out, you can turn it vertically and get a deeper beam by cutting this out and leaving the foam down in this half.
You can span up to a 30 foot opening fairly regularly with this block by adding a little bit of steel and cutting out the block using that formwork to your advantage to get a bigger beam to span the longer distance. How much block can you cut out? Well, you can cut all of it out if you need to, but then you’ve got to shore up around the outside. Any time you remove the center part of the meat and you leave these shoulders here, you want to put some shoring on the outside.
So that has to be reinforced? Yeah. Before you pour, you want to reinforce that on the outside. We’ve got some job photos that can show you that. You want to talk about that window buck? Yeah this is one of the styles of window buck that you can use. The stay-in-place wood, this was designed to stay in place. We put the lag screws in a full installation, we’ll have these all the way around, they’ll get locked in the concrete and hold the wood in place. You can build it removable and just coat it with form release, and then after the concrete is cured you remove the wood and then you’ll just have the concrete surface all the way around. Hollow metal frames work well too.
We leave the bottom of the cell open so you can pour through above. You’ll want to set these in place as you get to the windows to build a wall around them. We made this conveniently sized for our demonstration, but they don’t have to be, that was my point. You can set this window anywhere. These block are 32 by 16, but you don’t have to run on a 16-inch module. We can cut makeup block out of this very easily, you can cut your hole anywhere you want to put the window, so you’re not restricted in that way to either window height or spacing. We’ll go ahead and put some up on this side.
You pour so quickly. His question was, is the installer going to mix his own concrete, or is he going to order it? And, he’s going to order it, because the walls go up very quickly. We had a 3900 square foot single-story office completed recently, and it took a couple of weeks to stack the block and get the rebar in it, and they poured it from start to finish they poured it in under 3 hours, and most of that time was spent waiting for the Readymix trucks, so it goes very quickly, and that’s even going in lifts and vibrating in between setting the roof bolts and all that good stuff.
We’ll do a full bead like this, about like that, and you’ll do a full bead all the way up and down with that, set it, and you do the stretcher and the header joints with glue. In 10 minutes you won’t be able to get it apart. David, when you set that low-rise foam, do you have to wait and let it get…when you do the full install, before you set the block right away? Not at all. You know, a good illustration, this is almost zero expansion. It expands right out of the gun, so if I do that right there, that’s at its final volume already. It’s going to set up at that size, so you don’t have to let it develop or anything like that. You can do it and set it just as quickly as you’d like. It makes for easier inspection holes and things like that.
Clean outs at the bottom on the pour day, or you can come out, say your inspector wants to see that all of the bars are tied together and all of the rebar is in the wall, you take a hole saw like this on a cordless drill, come up to any of the joints or intersections of the wall, drill through that, take your piece of foam out, spray a little bit of this, inspect it, spray a little bead of this around it and pop that patch back in, and in 10 minutes, you can be pouring the wall. [Inaudible] You don’t want to get it on your fingers? It doesn’t hurt, and it won’t hurt you, but it will be on your fingers.
For weeks. Yeah, a couple of weeks, and fingernails until they grow out. I’ve had experience with that. Just like you’ll have yellow nails for quite a while. That’s the top half, the top snap-tie for our bracing. We’re going to get up into the tree with this one, it looks like but, we’ll show you how kind of a typical bracing is done, and you can start to see these cores starting to form up.
So we’ll do this and then we’ll put one over the window just to show y’all how that goes, and you can imagine there are a lot of different structural configurations you can use with this. We’ll use those to attach the bracing point, and the cool thing about those snap-ties is, after the concrete is poured in the core, you bend them back and forth, and they actually snap off back in the core, so you don’t have steel right up against the surface of your wall.
Normally we’d set a bigger cage of rebar right here in a lintel going over a window or door. Duane’s going to make it corner block for you. You can cut this with an electric chainsaw, or any hand woodworking tool. We found that this saw works better for making precise corners, but what you’ll see is you don’t have to order corner block with our system.
You can take a standard block and turn it into a corner piece, and not lose any square footage in the wall. We’ll take half of that and flip it over. It’s best to glue this on a pretty flat surface, I have no idea how flat this surface is, but you come here with the same spray foam right here, stick those together, and that forms a corner block for you. You can shore up the outside like that, let that set for about 15 minutes and give it a couple of good jabs in the core, and that will hold together, that block will be more than strong enough to withstand the pour once it’s formed up. And so you can set that, he’s got to core set the corner, and we’ll get that going. We’ll let it set, and then you guys can pick it up and play with it a little bit. You want to put the bracing on? Yeah. So the strength of the core in the long-term is going to be in the concrete.
Long-term, the whole strength is in the concrete. You’ll notice, when this wall is finished, it’s going to be pretty substantial, but we don’t account for any of that in the design of the structure of the system. It’s purely formwork that stays in place with insulation, fireproofing, sound dampening formwork. These are just some kind of standard strong-backs that we put on the outside of the wall. We put them on both sides to link those two sides up. These just act to connect the two together through the wall.
And then on one side or the other to kind of develop that and give it some strength. I’ll talk about some attachments while Duane’s finishing that up. This is a Bautex Wall Anchor. We also sell this item, it’s the same material, the ABS plastic that they have in the stringers in standard ICF. We could embed these in the block as a screw position, but you don’t need them in most cases, so we just send a box of them if you need them. Just put them where there’s a core, tap it through the wall with a hammer, and you’ve got a position to screw to. That being said, on the interior for things like sheetrock and so forth, you can screw and glue sheetrock straight to the inside of that without those anchors.
So screws will hold them just long enough for the adhesive on the sheetrock to set up, and it’s the same adhesive we use to put the block together and is also approved as a sheetrock adhesive, so you can use it for both applications, you can come in later and screw to that. It’ll be locked in the core, you’ll see it here, it’s secured there, he’s going to show you how to core out a hole if you need to. You can inspect it very easily, very quickly, if your inspector wants to check all of the joints and so forth. That can be glued back together later, or you can put connections in those positions.
You can put embedded bolts, J-bolts, you can use pocket connections; we’ve got a lot of details on our website on how to do different connection types. We integrate with almost any flooring or roofing system out there on the market, so you don’t have to use a specialty system with us. You can use whatever you’re used to using. This is a masonry anchor, you can use really any off-the-shelf brick tie. For cavity wall construction, you just cut in before you pour, find the core, which is easy to find the cores because it’s delineated by all of the grid lines, and then there’s one down the center. So you want to make sure you get it in a core, and that’s how you install a brick tie.
Then you come back, pour the concrete, that gets locked in place, you spray your air and moisture barrier over the wall and then install your masonry veneer. Fire resistance, I talked about that. This bead here, expanded polystyrene bead by itself, it will melt and it will burn, but when we encapsulate it in the concrete like we’ve done with this block, you can put a flame directly on the block and it won’t catch fire. If you did this with a standard piece of ICF, or standard piece of foam insulating material, you’d have melting and fire on your hands pretty quick.
This will glow red, it will stay like this pretty much as long as I’d like to do that. And that cementitious shell around the foam protects that block from flame, so it won’t catch fire. You get a little bit of smoke development. Our smoke development test, we rated a 20. You need below 450 to pass that test, and below 250 gives you an NFPA Class A product, which we are. Do you guys have any other questions? It’s hot out here. We’ll be sticking around and answering them. Whatever you’d guys would like to ask.