Summertime is all about getting together with friends and enjoying good food and drink in the great outdoors. The choices we make can reduce our impact on that outdoors and global warming without getting in the way of our enjoyment of the event.
We’ll start with the beverages since that’s where the guests (and hosts) will likely start. I was interested in finding out what was the most environmentally benign beverage and called my local recycling coordinator who wasted no time in telling me that tap water was my best choice. So I refined my query, I had heard that recycling 30 beer cans saved the equivalent of a gallon of gas - how many beer bottles, I wondered, would be equivalent to 30 beer cans. He did some research and we ran the numbers and it turns out that 385 beer bottles has the equivalent embodied energy of 30 beer cans. He pointed out that there was some minimal adjustment needed to account for the transportation cost of imported beer so this calculation was most accurate if applied to domestic beer in both bottles and cans. Ah-ha! I said, this gives me an environmental rationalization for buying that nice local microbrew! Maybe even to buy it in kegs and keep a kegerator in the garage! Actually he replied, the kegorator idea is a no go due to the carbon footprint of the refrigerator (regardless of the impact of the increased beer consumption) However, if you consider that there are 22 shots of bourbon in a bottle that likely has the embodied energy content of two beer bottles this gives you an environmental justification for drinking bourbon on the rocks or mint juleps. If a single beer can equals 12.83 beer bottles it is equivalent to six bottles of bourbon in terms of its carbon footprint. As a dedicated environmentalist I found his logic irrefutable.
But what about the kids? We needed to get them off the cans and plastic bottles that impart bisphenol-A into soft drinks, but “let them drink tap water” was not going to fly. We decided we’d have less of an insurrection if we made up a sun tea and fruit juice concoction. (And the cost works out to our advantage as well.)
The main course? Certainly not pork barbeque, though as a North Carolina boy I run the risk of getting my tires shot out for saying so, I’ve seen first hand the environmental cost of factory pork farming and one of the major precepts of sustainable cuisine is to eat less meat and more local vegetables. Lamb, even that shipped from New Zealand, has a low embodied energy content in comparison to grain fed pork and beef. Of the factory farmed meats, chicken has the lowest carbon footprint overall considering both embodied energy content and methane production. We can make points on both carbon footprint and embodied energy content by preparing meat and vegetable shish kabobs on the grill with range fed lamb tips or chicken thighs and local farmers market vegetables and Yukon gold potatoes. In general our goal is to reduce meat portions to less than ¼ lb per person by filling in the plate with delicious local vegetables and starches.
For the sides we’ll keep the theme going and instead of hitting the local grocery for tubs of coleslaw and potato salad we’ll sauté up some summer squash and onions and make up a great green salad with ingredients from the farmers market.
As for dessert I’d say the best thing to do is ask the kids what they want and make it happen. It is summer after all.
| The Menu | |
| Not-so-green | Much-more-green |
| Canned Beer | Mint Juleps or Bourbon on the rocks |
| Canned Soft drinks | Iced sun-tea sweetened with fruit juice |
| Shrimp cocktail | Salted nuts, cheese and toast, carrot sticks |
| Barbequed pork sandwiches | Lamb or chicken shish kabobs with local vegetables and quartered Yukon gold potatoes |
| Cole slaw and potato Salad | Fresh local salad with vinaigrette dressing |
| Dessert, whatever the kids want! | |
Recommended links:
http://www.oberlin.edu/recycle/facts.html
http://lifeandhealth.guardian.co.uk/food/story/0,,2097255,00.html
http://www.independent.co.uk/environment/climate-change/ten-readers-ways-to-cut-your-carbon-footprint-460822.html
http://health.msn.com/health-topics/cancer/articlepage.aspx?cp-documentid=100200558>1=31025
One of the biggest advantages of working with a design-build company such as Chandler Design-Build is that we have a track record of building our own designs and we have a data base of the cost breakdown on the houses we've built in the last eight years. So when clients ask us what something is going to cost we have comparable data somewhere in our system that can give us a good idea of what it's going to be. The issue is generally just the effort of measuring up and inputting the data and assumptions on ever-changing 1/8" scale pencil drawings we are working with in the preliminary stage of the process.
In the past that meant poring over the drawings with a scale and making guesses as best we could. While there is still a lot of "educated wild ass guessing" involved, we have recently added a tool to our system that improves both speed and accuracy.
It's called "Digital Take-Off" and it's one part of a design and construction management system from Digital Canal Corp. In many ways it's similar but superior to an older piece of software called "PlanSwift" that other builders may be familiar with.
The screen shot above shows what the interface looks like. I've just imported a digital photograph I've taken of a plan Beth is working on. It's drawn on a piece of thin trace (you can see the drawing below it on the table bleeding through) with no dimensions or indications of finishes or construction; it's got loads of offsets and 45 degree angles. To bring it into the computer I just lay it on the table and shoot a photo of it and drop the image into the client's folder in our computer.
The next thing I do is take a distance that I know on the plan, in this case the width of the living room and, to "set the scale," I drag my mouse across the distance I know. It asks me to type in the known distance, 22 ft. here, and the scale is set for the entire drawing.
I've set the tabs on my software to correspond to the questions my estimating worksheet asks me; Heated SF down, up, ext wall perimeter, interior wall cumulative length, number of windows and such. Pulling to the "Heated space down" tab, I drag my mouse around the perimeter of the building.
Once I have the shape I want I click the plus sign and I get an accounting of the area, (too big, we're trying to keep it under 3,000 sf) perimeter and other information that I can either cut and paste into my estimating software or export to Digital Canal's estimating package, Bid Builder, which is part of their software suite.
As I click through the tabs they prompt me to remember to measure, count, and export all the different elements I'll need to prepare a preliminary estimate for the house.
When counting items such as windows or fixtures it leaves a mark so you will know if you've left anything out or counted anything twice. Right clicking allows you to undo the last few points you've selected. It has a roof pitch converter so when you want to figure out how many roof shingles to order you can enter the pitch of the roof and it will tell you (you still need to add for ridges and valleys) Once the house is under construction the software will help with lumber and flooring take-offs and even figure rafter lengths and counts for you.
I bought Digital Take-Off at a special price the last day of the international builders show and they immediately assigned me a sales rep who has since sold me on "special deals" for their CAD software, Solid Builder, and the estimating component, Bid Builder. I'm not sure what the regular price on any of these items is since they are always doing specials. If this is something that would help with your building projects call Monty Alexander at 800-449-5033 ext 139, tell him I sent you. I have their CAD software which I got to replace Chief Architect and have started experimenting with it and will post about that here soon. He also made me an offer I couldn't refuse (thanks Monty) on Bid Builder so I'll be diving into that sometime soon as well.
I've been building custom homes for over 30 years, and I've framed more than my share with a crew, swinging a hammer myself back before we had these new fangled nail guns. Along the way I've grown somewhat particular about how I like things done and I've worked off and on with the few framing crews who could wrap their brains around what has come to be known as Advanced Energy Framing advocated by Joe Lstiburek (pronounced Stee-brick). As I've gotten increasingly involved in the green building movement I've searched ever more vigorously for a better way to build homes especially when it comes to keeping the framing dry and reducing lumber waste and impact on the landscape at the building site. Here's why I've settled on Table Framing as a solution that fits my business.
There are a number of new wall alternatives on the market these days. I like the thermal performance of Structurally Insulated Panels (SIPs) but worry about their performance in a hurricane and I like the simplicity of being able to fill my walls with pipes and wires at will and add the insulation later. Insulated Concrete Forms (ICFs) are a really fabulous innovation and I'll probably continue to use them extensively for high performance foundations and for all our radiant slab applications but I do worry about the embodied energy content and cost of the concrete and steel and I'm, again, not thrilled about the need to remove the insulation (and concrete in some cases) to install pipes and wires. Aerated Autoclaved Concrete (Hebel) block is a fascinating material but many people have expressed concerns about it's permeability to water vapor and its lack of compressive strength. I look at the flashing systems used to install windows in AAC and have serious concerns about moisture intrusion. I'm personally appalled that anyone can seriously advocate steel framing as a green building system when we have so many better uses for recycled steel and wood is such a renewable and low embodied energy content resource.
So I keep coming back to wood Advanced Energy Framing, its economical cost, renewable source material, ease of access for wiring and plumbing and most importantly the ability to wrap the house with a durable and repairable water repellant membrane to manage moisture intrusion. I think it is the best of a number of imperfect alternatives. But I've been frustrated by the slowness of the site building process and the willfulness of framing crews who revert to the old "more wood must be better" way of building and end up wasting materials and time.
Table framing the walls off site minimizes lumber waste (computerized cut lists optimize lumber utilization and what little waste is produced at the plant is converted to wood I-joists and used in the next house) Building the walls indoors on a special table made for the purpose means all the walls are square and tight. Floor plates are marked by a computer pulling information directly from the blueprints, minimizing errors. Nail patterns are better managed and generally exceed code specs. When we ask for 3 nails in a 2x6 we generally get four. Code asks that plywood sheathing be nailed 4" oc at the edge and 8"oc in the field, we generally get 3" and 6" and the nails are placed by a computer driven auto-nailer. It's not dependant on the attitude and conscientiousness of the worker in the field.
But the biggest advantage I see is that I can build homes in densely wooded sites without needing to stockpile and protect large stacks of lumber on the job and without needing to manage all the piles of cut off lumber ends so my sites stay cleaner and safer and the jobs get a huge boost of speed with roofs going on faster and the interiors of the homes therefore being subject to much less weather damage.
I participate in third party green building certification through the NAHB and that system awards me points for lumber optimization and scrap reduction and for not beating up the jobsite environment. Take a look at the following images and you'll see what I mean about the speed and quality of construction. These images were taken between Thursday 3-13-08 and Wednesday 3-19-08. Six days from subfloor to tarpaper on the roof. By working off site we can schedule the walls to be built while the floor is being installed and have the roof trusses built and ready to go up as fast as the wall panels can be tilted up and made ready. We cut weeks off the build time and improve quality at no additional cost.
Table framing is not any less expensive than on site framing and it's not possible for every house but the improvement in quality and speed and reduction in lumber waste make it a better value from my perspective whenever we can make it work.
After the I-joists were hung from the mudsill and inspected we got to try working with a material that we've been hearing about for a long time but until now had not had an opportunity to try. Warmboard is a subflooring material that is 1 1/8" thick and has grooves for 1/2" PEX tubing routed into it in different patterns corresponding to different ways you might wish to lay out PEX to heat a floor. In terms of raw cost per sq. ft. it cannot compete with a radiant slab but it has some interesting properties that make it far superior to all other staple up radiant options and in some jobs superior to radiant slab a well. This was one of those projects where it really did make sense.
This project will have 2,300 square feet of heated space so we needed 83 four by eight panels which, including shipping, cost $17,325.04 delivered to the site. By comparison 83 pieces of advantech sub flooring with staple up tubing would have cost us much less but would not have given us the advantage of being able to use oak flooring with antique rugs and still heat the house with our choice of solar, wood, or propane derived BTUs.
If we had used regular plywood under the oak and stapled up ½" pipe underneath we would have had much slower heat transfer to the home than the tight contact aluminum sheet we get with the Warmboard. To compensate for this we would have had to kick the heat in the pipes up to 140 degrees which would have meant that the "cooled" water returning to the heat exchanger from the floor would still be at 120 degrees. This return temp is too warm to effectively heat with solar and even presents efficiency issues with a Rinnai demand water heater (it's harder to heat water that is already hot). We expect the cooled water returning from the Warmboard to be barely warmer than room temp which makes it ideal for use with solar panels and optimizes efficiency with the wood fired boiler and Rinnai demand water heater that will be our back-up energy sources after the solar.
The Warmboard folks provided right and left turn full and half sheets, straights, fillers, and an elaborate schematic showing exactly how each board fit in the scheme. When we were finished we had used every piece and had one straight and one filler left over. If we had come up short it would have been a week or more back order from their distribution facility in so I was pretty content to have a couple sheets left over even if they did cost about $207 each. It took us a day and a half to install all the sheets and another half day to rout out all the special grooves.
The next project was to install the pipe and again the Warmboard folks had provided a lay-out and calculated the length of each run and identified the locations of the manifolds. We used 3,000 feet of pipe for this project which added $840.00 to the cost of the system. We glued the pipe into the grooves with silicone to keep it from making noise as the warmth hits the system and rolled it in with a lawn roller as we set it out. This took a little over a day with all the constant vigilance to keep the grooves clear of dust and debris.
The folks at Warmboard provide an installation plan and, at $207.00 a sheet, you can't afford to make any mistakes. We had to pull up one sheet at the outset and decided to assign one person to be in charge of the plan. At the end of the job we had two sheets left over...
The stuff goes down like regular ply except that it weighs over 100 lbs per sheet. I thought it was smart that they marked the pipe locations on the underside of the sheets so if we need to cut or drill in it after the finish floor is down we have at least a chance of missing the pipes.
Toilets and other items that would necessitate re-location of pipe are located and grooves get routed in ahead of time to allow the pipe to dodge the hazard.
Additional grooves get added to link floor sections and accommodate for all the bays in this design.
We made a spool out of left over plywood and 2" electrical conduit to allow the 1000 foot coils of PEX to roll out evenly from between a couple of ladders. Vacuuming out the grooves was critical and tedious.
A very thin bead of silicone is laid into the grooves and a lawn roller filled with water embeds the pipe into it very quickly. On the tight turns we screwed nail plates down over the pipe to keep it from popping up. The manifolds will be in walls 36" above the floor to allow air bubbles to accumulate and be expelled from the system through air vents.
The final project was to pull all the manifold tails back under the floor and pressurize all the pipe to 100 psf before the walls went up. Since the walls were table-framed off site there was little assembly done on the deck and the walls were up in a day and a half so wear and tear on the pipe was minimized.
PEX or PEX-AL-PEX?
Warmboard is generally installed with PEX-AL-PEX tubing, a type of tubing that was originally developed to provide an oxygen diffusion barrier so radiant heat installations could be used with old-fashioned cast iron boilers and pumps. This tubing combines a thin, flexible aluminum core with an inner liner of PEX and an outer wear layer of PEX and a waxy lubricant. It has doesn't have the annoying "memory" that PEX has which makes that product want to spring back into the roll shape it came in. You can shape it to any shape you like and it will pretty much hold that shape. It also has a far lesser coefficient of expansion than pure PEX does which makes it less likely to wiggle and squeak when a slug of hot water hits it in a radiant floor application.
But PEX-AL-PEX gets stiff in cold weather and doesn't feed easily through holes and over obstructions. And it's significantly more expensive than plain PEX. (For this project it would have been $1,400 more.) PEX-AL-PEX pipe uses proprietary sleeve and ring fittings and any scrap shorter than 200 feet generally ends up in the landfill as we don't use this type of pipe in potable water supply piping. PEX pipe is the same pipe we use with potable water installations so it uses the same crimp fittings we already have and 100% the scrap pipe can be immediately recycled into the same house.
When plain PEX is installed in a radiant floor application such as Warmboard it must be continuously embedded in a 1/16" to 3/16" bead of 100% silicone caulk in order to bond it to the aluminum to prevent it from slipping and "popping". The pipe is pressed into the silicone with a heavy weighted roller so that it displaces the air between it and the aluminum which enhances heat transfer. This process has the potential to be messy and prone to operator error in that too much silicone will keep the pipe from sinking below the surface of the board and too little can lead to a noisy floor. Still, it really is no more difficult or time consuming that wrestling with the stiffer pipe and I chose to use this system based on the enhanced contact between the pipe and the aluminum combined with the cost savings and my prejudice against the stiffness and proprietary fittings of the PEX-AL-PEX.
We'll install the Rinnai water heater and the flat plate heat exchanger and get the system up and running to dry out the Warmboard before we start installing the hardwood and tile flooring. At this point we have the system pumped up to 100 lbs so we can rest assured that there is no hidden damage to the pipes.
Get the details from the Warmboard installation manual for PEX tubing.
This house is being built to accommodate aging-in-place design principles so one issue we wanted to achieve was a step free access from an entry that was to be a slab on grade patio.
Our solution was to hang the floor framing inside the ICF foundation using top bearing joist hangers.
The engineering team at PolySteel specified that we had to remove the foam from the top 8" of the area under the joist hangers to provide good support for the 2x10 mudsill.
We tacked 12" galvanized flashing to the bottoms of the treated mudsills and then tacked sill seal gaskets to that so there would be an air tight fit between the flashing and the top of the PolySteel. The top sill is strapped down every four feet with hurricane straps and the I-joists are isolated from the foam and concrete with galvanized steel patches to help keep termites from tunneling into them. (This is in addition to a low toxicity soil treatment and borate based insecticide mixed into the foam at the PolySteel factory.)
We ordered all the Joists precut to within about eight inches of their final length. The scrap would have fit into a single trash can.
With all the pieces precut at the supply house the floor was framed and ready for inspection in a day and a half. It fits into the concrete foundation like a cork in a bottle.
We’re getting started on the Rockwell Residence which will be our entry in this spring’s Green Home tour. It’s pretty extreme green for us, so I’ll be writing about the progress as it goes forward. We’ll be using Insulated Concrete Forms from Triangle PolySteel to do the sealed crawl space walls. There will be a unique dropped I-joist floor system to help the building sit low on the site and make the front door handicap accessible. The walls will be panelized and the roof will be a Cantilever Truss System so the exterior soffits will be the same elevation as the interior ceiling to help let in more light. The Sub-flooring will be WarmBoard heated by a combination of the solar hot water, an outdoor water furnace, and a Rinnai demand water heater.
Chapter one The PolySteel Sealed crawl…
The forms come off the truck.
The forms are so light we were able to carry them down the dirt driveway by hand.
Soil conditions were some of the worst I've seen. Giant granite boulders and soft black muck. The footings were engineered by by a soils engineer with extra concrete and steel. We built forms to get above the stone and mush and lined them with black poly as a capillary break to help keep moisture from wicking up into the concrete and into the crawlspace.
Once the footings are poured we laid out the shape of the foundation on the concrete with string and glued the first layer of forms to the concrete with spray foam. Brennen went around with a hammer drill and a 24" long concrete bit and set all the ½" by 18" steel pins to lock the concrete to the footings.
Steel in the forms.
Once we had the forms stacked up to finished height we tied in the rebar for the top course bond beam and the bent up the vertical steel and tied it all together.
Once the forms are set and loaded with steel we attach 2x10 bracing to the forms with long screws into the steel embedded in the foam. Then we braced down to grade and aligned the forms to the lay-out.
The day of the pour we were racing to beat an impending thunderstorm, the storm won but we were able to pour in the rain because we were pouring on top of concrete. Still it was cold and wet and concrete went everywhere. Here Bradley Yoder, our coach from Triangle Polysteel, shows us how it's done.
As the pour went on the rain subsided. We vibrated the concrete down into the forms and shoveled more and more into the top to keep them full. It was good to have a big crowd, and a special pleasure to have the home owner, Paul Rockwell, lend a hand in the big push.
Here Paul is running the hose from the concrete pump while Matt and Brennen vibrate the concrete down into the forms.
The next day, strippjng the braces and getting set up for the I-joist floor framing.
At the press conference at the International Builders Show the press kept on challenging the NAHB spokesmen about the differences between LEED for homes (known as LEED-h) and the new NAHB National Green Building Program (NAHBgreen). The responses centered on the word “mandate” but the definition of that seemed to float between referring to governmental mandates that all construction be “green” and issues with the number of mandatory items required for a home to pass LEED-h minimum standards. The alleged cost of these programs was also a source of great confusion and rancor. During and after the conference I kept reflecting on how wrong headed all the tension between LEED-h and NAHBgreen is and how it distracts us and keeps us from getting our message out which is all about transforming the market and the way people build and buy homes and the decisions we all make about remodeling and maintaining the homes we have.
Let’s get one thing very straight here. LEED and NAHB are on the same side. We are both focused on helping the market shift to recognize energy efficient and resource efficient building systems that result in well maintained houses that are healthier to live in than the status quo and use fewer materials to build and less fuel and water to live in and last longer.
There are significant differences between the two programs. LEED-h is focused on serving the “Top 25% of the Most Environmentally Conscious Builders in America”. It is a green building program for high end, high performance homes and, as such, its requirements are very rigorous and the standard of proof in terms of third party verification is very stringent and therefore more expensive. The “NAHB National Green Building Program” is aimed at every builder in America not just the top 25% of the greenest builders in America. Its standards of proof are designed to make the program meaningful and verifiable but not onerous to participate in from the builder’s or the verifier’s perspective. A pre-construction plan review, two site visits and a paper trail showing receipts and photographs of systems implementation are all that are required. Third party oversight and “consulting” are minimized. The system is designed to make it easy and inexpensive for builders to step up to green building best practices. In that builders are going to be using the Green Certificate as a marketing tool when they sell their products, the documentation has to be stringent enough to stand up in court if the builder is accused of “green-washing” by cheating on the certification.
I have been having all my homes scored to both LEED-h and NAHBgreen as well as to the North Carolina version of the NAHBgreen system that our state has modified to fit our particular climate and humidity and water conservation challenges. But I’m an NAHBgreen builder because I want to be part of improving the way America builds homes and I believe that NAHBgreen has a better chance of creating a market shift than LEED-h does.
If we want to make a difference we need to be able to build green homes for school teachers and factory workers and cops and the real life beer drinking folks who make this country work. Not just for the movie stars and Prius driving, granola crunching, chardonnay sipping, crème de la crème.
Ed Begley and Brad Pitt need homes too and I’m thrilled to think that they are building structures that push the envelope for zero carbon footprint LEED-h platinum excellence. But I spent some time talking with LEED-h builder Steve Glenn in Los Angeles the other day about how much it costs him to build one of these super-green homes and he’s looking at $400 per square foot for construction (not including land costs.) His cost for LEED-h certification is $5,000 - just for the report card! Maybe people in LA can afford that but I would have a pretty hard time selling it in Carrboro, North Carolina. My cost for LEED-h certification is only $3,000 here in NC for the same report card that Steve pays $5,000 for in LA but the NAHBgreen report card is $150 here and across the country.
If we care about making green building affordable and accessible then we are going to need a program that has an affordable level of entry and is accessible to the average builder. NAHBgreen is that program. But that doesn’t make us the enemy of LEED-h. They provide a very challenging program with a stringent verification; NAHB provides a very welcoming program with a lot of peer support and encouragement for new builders taking the first steps towards Energy Star and Green certification. The market is big enough for both programs and it’s going to take both to move our country away from the crises of out-of-control consumption we are in.
Builders and developers worry about government mandates and their concern is justified. Our local Orange County NC County Commissioners have made it clear that they want every home and building built here to be Energy Star and Green Certified in two years. The local Home Builders Association has made it clear that we will not buy in unless our National Green Building Standard is one of the definitions of green that are accepted by the county. Imagine if they adopted the LEED-h standard instead, and only the top 25% of the most environmentally conscious builders in America were allowed to build here. A move such as that would have a devastating effect on affordable housing in our county.
When I talk to builders about LEED vrs NAHBgreen, I find it is useful to compare it to a religion. In all too many ways it is an apt analogy. The LEED-h providers are like the high priests and priestesses of green, up in the fancy stone church on the rich side of town. The NAHB crew are the folks in the revival tent down by the river. You don’t need to take a bath and put on nice clothes to come to our church. But we’re both preaching from the same gospel. “Listen up Builders and Architects of America, there’s a better way to build homes that doesn’t cost much more but saves energy and water, and lasts longer, and makes for much less warrantee expense, and it’s a better way to do business, and it’s easy to get involved.”
The enemy is not the high priest mumbling in Latin up on the hill. The enemy is those who are still building inefficient, drafty and leaky, minimum standard homes that waste energy and water and cost more to maintain and will have a shorter life span than homes built with existing green building systems. But the goal of our program is not to attack those builders either, just to bring them into our tent and show them how easy it is to join our congregation.
