Welcome to all of you, and thank you for logging in for our presentation today. I'm George Spence, as Brenda told you, and this is the PCI presentation, Total Precast Concrete K-12 School Case Studies. As Brenda explained, this is a registered AIA course, and we have four learning objectives today. We're going to learn how to do total precast schools using insulated wall panels, low bearing, and double-T floor and roof systems. We'll examine design, detailing, and look at life cycle cost. We'll use case studies showing energy savings and cost savings using total precast. We'll include an infrared thermography study, and we'll talk about the sustainability resilient aspects of total precast. We'll also take a look at the energy codes. First, there's numerous advantages for using total precast concrete construction for K-12 schools. I've listed about six of the more important ones. One is speed of construction. The end date is always the same for schools when the students start back, so any delays in the construction schedule have to be made up, and precast facilitates accelerating the construction schedule. It's proven cost effective against other building systems, and we have aesthetic versatility. We'll show you a wide variety of options for the design team. A very important aspect, it facilitates building on tight job sites. Replacement schools or tight job sites, restricted job sites in urban areas. Total precast with insulated wall panels is a very energy efficient system, and precast concrete is durable. Well, one might take a look at these benefits and say, why aren't all the new K-12 schools built with total precast? Of course, there's several reasons for that. Inertia, bias, politics, tradition. My granddaddy bricked them, my daddy bricked them, and I'm going to brick them. Laying these reasons aside, a comfort rational school facilities designer might also think, everyone claims to have a better mousetrap, and this probably contains a lot of marketing hype, and I'm going to discount this information somewhat. Well, to increase our credits in these benefits to a very high level, I plan to offer a convincing set of case studies in today's presentation. I'm going to start with the easy one, durability. Concrete and total precast concrete is durable. I did this school in 1973. I live about three blocks from it, and I can see it from my house. My kids went to school here, and this is a recent photograph. It looks as good today as it did 43 years ago when we turned it over to the school. It had required no repairs. I've walked it annually or fairly often with the facilities people just to check on it, and their policy is on the caulking. About 80% of the original caulk is still serviceable in place. When they found damaged or failed caulking, they would replace the damaged area with the new caulking. Another thing they like about it, graffiti sometimes winds up on school walls. They built their own sandblast equipment, and they easily, quickly remove it the next day. This school system currently has a two-year contract to renovate every classroom one-by-one in the two-year period, putting in new modern LED lighting, replacing old 70s fluorescent fixtures, and make another upgrade to the interior. However, not one single dollar was required in the contract to renovate or repair precast. This is the most famous concrete building in the world. It's been functional occupied space for about 2,000 years now, and the precast concrete on this high school has the same attributes. It's my opinion that if the owners of the building keep the roof repaired and the weather envelope maintained, this building will last at least another several decades and perhaps even 2,000 years. Precast has other advantages, too. It's fire-resistant, storm-resistant, and earthquake-resistant. If it's in a seismic zone, we design the connections and the panels for seismic conditions. Look at the architectural options of wide variety. We can do virtually any color, form, or texture. We can mix all colors of limestone. For schools in particular, we can cast in a brick veneer. This is five-eighths-inch thick. It's a real brick fired, made with the same clay the brick manufacturers make a full brick, and fired and delivered to the plant for casting the panel. If you're in a historic district or city, we can make historic compatible designs and execute them in precast. Here are some of the options. We can, of course, do reveals. I mentioned the brick veneer, which is popular with schools. This is a sandblast finish, which is a popular finish. This is retarded, which a chemical kills the cement on the surface, and you wash it out, and it has a much brighter... The stone shows through with this original reflective surface. Using a form liner to make stone block patterns. This is a form liner to make a real pattern that was bush hammered. We could do any brick pattern, running bonds, Flemish bond stack bonds. We can do any kind of mortar joint pattern. We can do a raked to grapevine, whatever the designer requires. We can buy the form liner with that mesh joint. We can do, as you can see here, multiple patterns. I want to point out that this is not 2,000 or less PSI mortar in the joint. It's 5,000 plus, and usually it's about 6,000 plus concrete in the architectural precast and structural precast panels. The big advantage, for some mortar leaks, you put weeps inside and have to keep them maintained, and they'll do a lot of trouble, but 5,000 PSI plus concrete is impervious to water penetration, so this wall will not leak. Here's an example of some architectural details executed in precast. We've got arches and cornices and columns and column capitals. It's a very handsome gymnasium from McEachern High School. We can also do sleek modern designs, precast lenses, almost any design the architect has in mind. Let's go to a typical construction of a school. This is a typical classroom wing, low-bearing, thermal-efficient panels. I'll show you how the panels are laid out. In this particular case, they were 12 feet wide and 45 feet tall with three-punched window openings. In this case, two panels made this classroom 24 foot wide. We can go 24 to 28 feet wide with two panels. This particular classroom has 19,000 square feet, and it was erected in eight working days. Here's a drawing of a section to a typical classroom. We've got low-bearing insulated walls on the two exterior sides, and then we make one of the columns and beams down one of the corridor walls, and then an infill with either non-low-bearing masonry or metal studs and drywall. There's a reason for this. We can do a solid wall or double-loaded corridor walls, but to add flexibility for future changes in moving doors around, moving classrooms around, having the non-low-bearing partitions facilitate flexibility in the future. Inevitably, the principal comes in and wants to move a door around or change some detail. But it's not required to be vertical low-bearing panels. In this case, we've got columns and beams. The spandrels are actually L-girders that pick up the double T floor load and roof load, so we can go horizontal designs and different ones layout. Here's a before and after. You can see the two spans of double Ts and a column and beam line down one corridor wall, and once it's finished out, it looks like any other normal school facility. Here's a case in the main entryway and hallway with the columns and beams infill block being finished out for the final finishes on it. In this case, on the media center, we designed the double Ts to be erected on a slope, and this allows a much more spacious, higher ceiling in the media room. One of the important things in a total precast school design is early up in the shop-drawing phase to have complete coordination with MEP. It's very important that we put any inserts for hangers or any punch openings, penetrations for MEP to run through the precast. Holes can be cut later, but it's a much more difficult process, so it's imperative to get it on the shop-drawings up front. Here's some more shots of construction. You can see the insulation in the wall panel. The backside of the panel is a hard trowel and painted with brick veneer on the face. In this case, this is a total lower bearing precast panel with insulation. The architect wanted to put some accent stone on it, so the stonemason just shot tie wires into the precast and laid up the stone by hand. In this case, classroom, they used metal studs and drywall for the demising walls except concrete block wall on the entryway. Notice that we do cast electrical boxes into the precast walls and run the conduit up above the ceiling line. In many cases, the electrician actually comes out to the plant and pulls the cables. All he has to do is wire the panels in when he gets to the job site. Here's some more interior views. We also do the precast stairs in the schools. This is a case of a monumental stairway at the entryway that's all precast. Notice in the gymnasium, most gyms have a span that exceeds the economic limits to precast double T's. We can perhaps do this span, but it gets to where steel joists are less expensive. But all the low bearing walls are precast. In this case, this is a precast wall. The reason it's a precast wall is the theater is behind this. These panels are low bearing and go up to the parapet in the theater. The back side of the wall is at the corridor. You can see it makes a very handsome precast corridor wall when it's painted out. Let's change to accelerated construction schedules. Newton County High School is a 365,000 square foot facility. It's one of the largest schools in Georgia. It was erected in 90 working days. That meant we were turning over 4,000 square feet per week of functional space to the contractor. He was able to get his MEP and glazing and other trades started inside. It was a two year schedule and he had a lot of work to get done too. The fact that we could turn over so much space each week to him kept him and his other trades busy and working. This is Tucker High School. This aerial photograph is the entire school campus. The design team tried to get Tucker to buy a larger tract of land and move the school and start over. The first school was built here in 1919 and it had been replaced twice. The people of Tucker said, no, this is where the school needs to be and that's where it's going to stay. It's a two phase project. The first phase was to build these two classroom wings, four story and two story, and keep the existing classrooms occupied. We had one year to do this. We were able to set up two cranes on the site and work coming off the road without disturbing the students and erect the precast. The yellow box shows the entire size of the job site. We started March 3rd in 2009 and finished May 29th in 2009. We were turning over, in this case, we had such a tight schedule we were working extra time on it. We turned over 20,000 square feet per week of functional space to the contractor in this case. This was a design build job. The contractor got us on very early in the job with the design team and we helped put the project together and work out the schedules. Notice that we erected the precast within a foot and a half of the occupied classroom areas. Twin Rivers Middle School is about 232,000 square feet. We erected it in three months and we were turning over 3,800 square feet of precast per week on this job. You can see the crane in the three story classroom sitting in the footprint erecting. Here's an interesting observation. I took the picture at the bottom from standing on top of the three story classroom. The site has a middle school. This middle school total precast built on one end and the school board on the other end built a new high school. Both jobs were lit in August the same year and both jobs had to be completed two years later in August in time for school to start. The contractor on the high school just barely made his deadline. He had to really rush at the end to get the high school ready. However, the Twin Rivers contractor was able to turn his total precast project over in six months earlier than the August deadline. It gave the school plenty of time to move in and set up and get their operations going. I mentioned tight job sites is another advantage of precast. If you have a very tight job site, it's going to be hard to access and no lay down area. It's a flag that you should take a look at the total precast. In this case, the high school football stadium is on the east side of the project. There are academic buildings on the north side and the west side. All the lay down areas we have for the entire job is this little triangle here. We had to bring loads in and the claims in the footprint started at the north end and erected the gymnasium back this way out. Here's another one. This is a replacement school. The Wheeler High School was obsolete and they decided to replace it on the same site where it was. In the meantime, over the years, more modern buildings that were still serviceable were built all around the old high school building. When it was torn out, we had to come in and erect just an expansion joint between the precast walls and the old building. This wall is this building up here. We erected it back on the road. Back to our high school, we had two cranes on the job. We had two roads in the site, one turning off the main road and one coming in the back side. We added the two-story addition, like I said, up against the occupied classroom. The yellow shows the entire job site. The campus is so small, we had to even add this 200-car parking deck up against the property line. You can see this road is up against the property line. We built a precast parking deck up against the four-story classroom. Let's talk about energy conservation. Energy conservation is an important part of sustainability and resilience. This is a widely accepted definition of sustainability and resiliency out there. I've defined it for our purposes. Sustainability is our capacity to endure, and resiliency is our ability to adapt. One of the most important things about sustainability and resilience is energy conservation. This is a U.S. energy chart that shows that about half the energy used in the United States goes into buildings. More than industry, more than transportation. For us in construction, there's a small 5.6 percent of the energy goes into construction. That would be embedded energy spent building the building. Unfortunately, a good portion of that is solid waste that goes to the dump, which all of us need to work on reducing the embedded energy to the best we can. But the big slice of the pie is building operations. Life cycle assessment studies have found that in a 50-year life cycle, the energy to operate the building is 96 percent of all energy, the total energy of the building that goes into the life cycle. Only 4 percent of it is for construction. So for the opaque enclosure, the most important thing to do, obviously, is to insulate. As far as sustainability, precast we use local materials, all shipped not within 500 miles, but usually within 100 miles or 50 miles. The closest quarry and cement plant and sand sources. We do use recycled steel for our reinforcing and for our precast strands are made of recycled steel. We use additives such as fly ash and other non-cement fillers to reduce the amount of cement in our concrete mix and still get proper strengths and concrete properties. There's no junk waste. Here's Tucker again with a load, pulls it off the road, the crane picks the panel up, puts it on the building, the truck leaves empty. There's no waste and no side disturbance. Concrete has low embodied energy, especially compared to steel, glass, aluminum, other construction materials. At the end of the life cycle of this building, it can be recycled. All the steel can be recycled and the concrete ground up into aggregate. It's resilient because of the energy efficiency of insulated panels. It has reduced heating and cooling costs, which future-proofs it against higher energy costs, which everybody expects, and climate changes, which we don't know how to predict. It's also flexible. As I mentioned, this school has all the interior partitions are non-load bearings. They could be stripped out of a new floor plan made up. They could be converted to office space or a data center or easily converted for other usage. We've talked about the durability. It's robust, fireproof, stormproof, and low maintenance. This is the cover of ASHRAE 90.1, the 2013 edition. It comes out every three years. 2016 is due out this fall. This is not the energy code. It's the national model energy code. States and local code authorities sooner or later adopt all parts of the 90.1. Some states are still on 2004. Some are using the 2007 edition. But sooner or later, what ASHRAE does, and this usually becomes code in most areas, and it's also the basis for LEED and other – Green Globe, Build America, Energy Storm. It's real easy. What it does, it also gives you the R-value of different opaque systems to build a building, and it's easily accessible. ASHRAE designs the United States up into eight energy zones, and let's just take, for example, Energy Zone 3, and all we have to do is go to the table Energy Zone 3, Climate Zone 3, and go to Table 5.5.3, Climate Zone 3, and it gives you the R-value for different building elements. For instance, R-25 for a roof, that was R-15 for decades, and in 2007, they moved it up to R-20. In 2010, they moved it to R-25. Notice the lowercase C-I abbreviation. You see this several times in these columns. This stands for Continuous Insulation, and I'll get into the definition of Continuous Insulation in a minute, but what we're interested in is precast walls. Precast has, by ASHRAE's definition, thermal mass, and we're also doing a Continuous Insulation wall panel, and notice that we have an R of 7.6 C-I required for minimum insulation, and you'll also notice that's the lowest number in this table, R of 7.6. There's a reason for that. These R-values, ASHRAE and the Department of Energy have a lab where they test different building materials and building systems, and what this table represents is what they think is the most cost-effective insulation for these types of wall roofs, opaque enclosures. This R-value for insulation is based on steady-state test, however, if you do a dynamic thermal transmission analysis of concrete, where you set it up to test for 24 hours where the temperature goes up and down, it has an effective R-value, that kind of test, of about R-5 or 6, whereas the concrete itself only has about R-1, so effectively, if you add that to the R-7.6, you've got about an R-13 wall in place. Continuous insulation, this is the definition in 2013, is insulation that is uncompressed, and uncompressed was added in 2013 for the simple reason that you've got a metal stud wall with a vat and put a duct or a drain pipe in it and it presses the vat flat. The R-value there is zero, so it's no longer continuous insulation. It's continuous across all structural members without thermal bridging, in other words, you can't put solid zones or metal sections to the wall to hold the wall together, other than fasteners and service openings such as louvers and vents. The way we achieve this, we run the insulation continuous with a front wife and a back wife, and when we have a lifting point or a connection, we'll indent, recess the insulation, it's still continuous insulation, and when we figure the R-value of this panel, we take into consideration, let's say, two inches and four inches areas in the panel, the old way was to put solid zones in here, and that's forbidden if you're going to have continuous insulation, because solid zones will reduce the R-value by as much as 50 percent in the panel. When we get to a window opening or a door opening, we also neck down the insulation where the window subcontractor has a place to mount the window frame and also a shoulder to do the caulk it out and make sure it's weather tight. At the request of some window subcontractors, we'll put in a wood blocking for a nail strip rather than continuing the insulation at the edges, still is considered continuous insulation because of the high R-value of low conductance of wood. When we turn a corner, we of course turn the insulation in the panel where it meets up with the insulation in the adjacent panel, and then to make it continuous insulation, we come back and put insulation in the joint, either foam or mineral wool, and then caulk out both sides where it's protected from the elements. In the roof, we turn the insulation out of the panel where it corresponds to the insulation in the roof deck. So what we wind up with, we think, is an ideal panel. It's insulated from edge to edge and top to bottom, and by ASHRAE 90.1 definition, it meets the requirements for thermal mass. We can make it load-bearing. We actually, with this system, we can make it a composite panel where the 8-inch panel acts like a, with 4 inches of insulation, acts like an 8-inch solid panel structurally. 5000 PSI concrete is impervious to water penetration, and all these panels are above 5000 PSI. It qualifies as an air barrier, as long as it's caulked out effectively, and it's an effective labor barrier. Block and brick cavity walls have some of those traits, and you can draw on paper continuous insulation on the architectural drawings, however, when you get out of the field, the mason invariably knocks a hole in the insulation of every tie wire, every shelf angle, every window opening, every door opening. So in practicality, you do not have continuous insulation, and we've got some thermal imaging I'm going to show you to verify that. And when you go to metal studs in bed, you've got even bigger problems. ASHRAE has a knockdown table, R19 is only worth R7.1. This is a thermal image in a school, you see the computer, it's inside the computer desk, and the walls are a nice, warm, pleasant temperature, but every time you get to a metal stud, it's a heat sink to the wall, and the heat is rushing out of the building. One of the goals of all designers is a net zero energy building, and before LEED, before ASHRAE, before Columbus, the Native Americans of the desert southwest had designed their own net zero energy building. They found out with their Adobe HUD, if they made the wall about 18 inches thick, the heat wave through that wall takes about 12 hours. So when the sun is shining on the exterior wall at noon, it's midnight before that heat gets inside, so inside is warm at night, and by then, heat is being radiated back into space in the clear desert skies, and it reverses the cycle, so by the time you get around the noon, it's cool inside. This works around the clock and works in all seasons, and incidentally, this Adobe HUD has been occupied in space for about a thousand years now. Researchers have found that 16 percent savings for thermal mass in climate zone three versus standard metal frame steel buildings in the desert southwest, the savings are in the order of 25 percent, so it's still active in that climate. It's active in most climates, and helpful, except if you lived in Miami, you probably wouldn't want to live in an Adobe HUD. It'd be pretty hot. There's two advantages for thermal mass. The first is the time lag, the Adobe HUD effect. It takes the peak energy for the building and transfers it to a later time, and in most areas, you can buy off-peak energy from the utility company and save money on your utility costs because you're buying it off-peak. The other advantage, it dumps down the energy required to heat and cool the building. That's because you're working against the average rather than the peaks, and so you have a savings of energy required. A third advantage, if you rerun your energy study, you can reduce the size of the HVAC equipment, reducing the upfront investment in the cost of maintenance for a smaller unit over the life of the job. I mentioned that precast is effective for vapor barrier. It is a pretty good vapor barrier. The 8-inch panel, what we usually use on the K-12 schools, has a permeance of about 1.0. In most climate areas, that's sufficient. If you're in a hot, humid climate or have extreme cold weather, you may want to add a vapor barrier. We can do that by adding a polyethylene sheet inside the panel up against the styrofoam or by the styrofoam with a polyethylene sheet laminated to it and bring the permeance down to 0.03 for 10-mil polyethylene, so we can design it for whatever the requirements are for the climate zone it's built in. Don't forget to seal all penetrations and joints to make sure it's a vapor barrier. We also check it to make sure that we don't have sweating inside in winter or outside in the summer. What we check is the dew point against the temperature gradient in the panel. As long as the dew point is well below the temperature gradient, there will not be any condensation. We check it for wintertime where it's 30 outside, 70 inside, dew point stays well under the temperature gradient and there's no sweating inside. In the summertime, a typical 90 degree day with 70 inside, the dew point still stays below it. Of course, if you do have a problem, all we have to do is add the vapor barrier. Let's get into our case study on energy efficiency. The basis of the study, the Twin Rivers Middle School has, as I mentioned, a three-story classroom wing, a full middle school built from scratch. It's built by Gwinnett County in Georgia. Here's the layout. On the right-hand side is a three-story classroom area and on the left side, gyms, media and cafeteria and so forth. It was built by Gwinnett County, which is the largest school system in Georgia. It has a school population of 160,000 students. It owns 115 K-12 facilities, a big school system with a lot of schools. Gwinnett County worked with me for this study. First thing we want to do is compare apples and apples. They have, for new schools, they have a standard size of high school designed for 3,000 students, middle school for 1,800 students, elementary school for 1,100 students, so we want to compare Twin Rivers with other middle schools. Furthermore, we checked the energy usage and high schools use more energy as you expect and middle schools use more energy than elementary schools. Again, we want to make sure we compare middle schools for middle schools. We've selected three other schools to compare to Twin Rivers in the Gwinnett system. All four schools were built within three years. All were built to the same building codes. All were built to Gwinnett's standards for middle schools. All of them have almost identical square footage and have about the same student body. We're going to take one year of energy use for these four schools and compare them. First, we pull all the middle schools in the system, the energy usage, and the units here are 1,000 BTU per square foot per year. We'll use that same unit all the way through this analysis. It turns out Twin Rivers, the total pre-K school, has the lowest energy usage of any school in the system. The free brick and block schools have a pretty good, they're way below the school average for middle schools. They're not bad. They're obviously not as good as Twin Rivers. We compared them and it turned these numbers and we found that the brick and block cavity wall schools use about 17 to 20 percent more energy than the Twin Rivers middle school. The next thing we did, we hired Atlantic Southeast Infrared to do an infrared thermology report on all four buildings. Let me say a few words about infrared thermography before we go forward. First, infrared, by definition, is invisible. So to visualize the temperature gradient, the thermographer picks the highest temperature and lowest temperature in an image, in this case, the highest temperature was the walls in the lobby inside the building and the coldest temperature was the sky, clear sky over the building at the lowest temperature. And then he uses an algorithm to spread the visual spectrum, pixel by pixel, between those two points. So you have red, orange, yellow, green, blue, indigo spread and it gives you a visual representation of the temperature in the image. In some other background, you need a good delta T, so the best time to do it is a little cold weather. You can see this on nights that were below, about freezing in February of the year. And you got to do it late in the evening because you want all the solar gain from the day to dissipate and not influence it. And it needs to be a windless night or very low winds because wind currents cause distortion in the thermal image where it's not reliable information. With that in mind, we started with Twin Rivers and I'll show you this is going to be the same layout for all four schools. We started inside, took an inside thermal image and there's a photograph of what the wall looks like. And then we went outside for the corresponding area and this is the outside thermal image with a photograph of the outside. I'm just showing you one, but the demographer took numerous readings on the walls. Another thing it can do is take the inside readings, the outside readings, the averages and it has a program to compute the observed R-value of this wall between the thermal image inside and outside. So this is Twin Rivers and you can see the wall has a pretty uniform temperature. There's not much variation in here, 76 down to 74. And when you go outside, you got the same thing. It's a very uniform heat flow through the wall, even temperatures on the outside. So the demographer has a reading scale. He rated Twin Rivers very energy efficient and he had an observed R-value of R18.6. Very energy efficient. Next we went to Gwinnett and this wall is pretty uniform on the inside. The temperature is pretty steady. This hot red spot over here is some kind of a cabinet up against the wall which caused that to be red. That's the highest temperature in the room. So the walls are a real uniform color. They're about 75, 76 degrees. And when we went outside, you can notice that the control joint in the brick block, the insulation is missing and it's a soldier course and the insulation is missing. So it's got some... It's not really continuous insulation on the outside. Nonetheless, it was rated energy efficient. Not very energy efficient like Twin Rivers, but energy efficient and had an observed R-value of 15. The next school, Lanier, inside, this is hot up at the top and cold down at the floor and I'm guessing this is more circulation problems than problems with the wall. Anyway, it's not a very good temperature pattern for the comfort of kids inside. And when you go outside, it's got similar problems. You got some thermal flow that... uneven thermal flow through the wall. So it's not continuous insulation. It nonetheless was energy efficient and had an observed R-value of R13.2. In the last school, Tricholm, you can see middle school, inside wall is pretty uniform in temperature, nice warm wall for the comfort of the students inside. When you go outside, you see the same similar problems where you don't have continuous insulation and there's thermal leaks through the wall. It was still rated energy efficient and it had an observed R-value of R12.7. So putting the R-values in the chart, you see that it runs from R19.2 for Twin Rivers down to 12.7 for Tricholm and I also put in for comparison the energy use, 1000 BTU per square foot in the adjacent column and charting it out, you can see easily that as the R-value goes up, the energy required comes down, as you'd expect. Our conclusion from our studies of these four middle schools is that insulated precast walls perform significantly better than brick and block cavity walls. Using Twin Rivers is another example in Gwinnett County. This is public bid information, available to the public. It bid for $23,180,000 and using the square foot, that's about $100 a square foot for the school. Terry Gladden was the Director of Facilities and Operations at Gwinnett at the time and he said that the total precast, and they know what schools cost, being as big of a constructor school as they are, that it was 10 to 15 percent less for the multi-story brick and block schools in the Gwinnett system. In other words, if it's a three-story, a multi-story, then it's cost-effective and less expensive than other construction systems. Gwinnett believes in that practice, their practice is to design multi-story compact designs because it minimizes roof area and exterior wall area, which minimizes heat loss or heat gain and also maintenance. So Gwinnett has built, in the past, in the 21st century, over 60 schools and in the last eight years, they've built six total precast buildings and all of them have been multi-story. It includes an elementary building, which was on an urban area and the only way that they could expand the school was to go up. We've done middle schools and high schools for Gwinnett County, and they have some sort of general guidelines that a single-story building, it's more economical to go brick and block, although there's no reason we can't do it in the precast, we're not cost-effective. But on the multi-story schools, freeing up, total precast is cost-effective. The more stories, the more cost-effective, and the reason for that, as the mason goes higher, he charges more per square foot for his masonry work. As precast goes higher, we're putting up larger panels for less erection cost and our cost per square foot goes down. So our conclusion is that total precast schools are significantly more cost-effective on multi-story schools compared to brick and block and other building systems. This completes our program, but I want to just quickly review that precast is proven cost-effective. Speed of construction is a very important element in K-12 schools because of the deadline for opening up the school for students. I hope I've convinced you that our precast design is thermal efficient, and we have plenty of aesthetic versatility available for the design team. It's durable, low maintenance, and it facilitates building on tight job sites. So just keep in mind, if you've got a tight job site, it's a good time to call in the precast for some advice on how it can be built. And we believe that total precast schools are sustainable and resilient. Thank you for your time, and I think Brenda, if she has some questions, I'd be happy to answer them now.

total precast construction

K-12 school

case study

energy efficiency

sustainability

durability

cost-effectiveness

thermal efficiency