Metal roofing, a very green product

Metal roofing is a very green option for several reasons. First of all it can be designed with almost no waste. Most roofing materials have at least a 10% waste factor. The elimination of waste means less materials purchased and less waste to dispose of. What little waste there is, is 100% recyclable. Metal roofs last longer meaning less maintenance over it's lifetime, it is likely the Melad's will never have to replace this roof in their lifetime.     

The one thing that creates more work and by more I mean a lot more, is the chimney sticking up out of the roof. This one feature of the  house turns 4 pieces of metal roofing into 35 different pieces that all need to be custom fabricated to correctly flash round it. It takes more time complete than the rest of the roof along the south side. The rough plumbing and electrical has been completed. On to the siding, HRV, solar chimney and heating system next.

Tom Pittsley

Solar chimney? What is it? and some really important steps to insulating a foundation

We are using a passive solar cooling technique in this home that is referred to as a solar chimney. A solar chimney is a little hard to explain but I will do my best. To fully understand how a solar chimney works you need to know a little bit about building science and the term commonly referred to as the " stack effect". The stack effect is what happens within a home when warm air is allowed to escape from your roof or through your attic. Something we try hard to stop in most homes by air sealing the attic space. The pressure created from the stack effect causes air to be drawn in from other places in your home, commonly your basement or a leaky envelope and windows within the home. Not something you want to do on a normal basis. The higher the point in which the air escapes the higher the pressure gets.

   This home uses the stack effect to our advantage. We are building a box located on the roof of the home. This box will not only contain the wood stove pipe but a whole house fan system as well. This box ( chimney) will be uninsulated and covered with a dark siding material. The heat created within the chimney will want to rise and escape from the vent pipes located on top. When the insulated (R-38) doors to the whole house fan system are opened, this will create negative pressure within house. In this home we are able to control where the air entering the home is able to come from. We have placed windows low to the ground on the north side of the house that need to be opened to allow the chimney to work. This will draw cooler air in from the north, fully shaded side of the house. If the system does not provide enough natural ventilation the whole house fan can be turned on to really move the air through the house. While not enough research has been done on solar chimneys to fully calculate how much cooling effect this will have on the house. It will be interesting to see how well it works next summer. What I did feel was the effect it will have on the building when constructing it. The last piece of the chimney was the top and when I was placing it I had to hold it down and could feel the air trying to escape, it wasn't even a warm day.

Foundation insulation, important steps!



  Foundations in most homes have little or no insulation at all and it has a negative effect on the whole house. Most basements here in the northeast contain the mechanical systems of our homes.( heating, domestic hot water and cooling) When these spaces are not conditioned we loose a percentage of our energy to this location. Conditioning this space for most homes means running a de-humidifier to control the moisture and consuming a large amount of electricity in the process. In this home we are using a better approach that includes insulating the foundation on the exterior from the footing all the way up to the sill of the home. We are using a product called Geofoam that is made of high density EPS, 2" thick with an R-11 insulation value. While building codes here in MA require you to insulate your foundation most builders stop this insulation at ground level, leaving a large hole in the homes thermal envelope. It does create additional work ( insulation, stucco and flashing) to do this but the result is a much better home in the end.

The other area of the foundation that needs attention in the basement floor or slab.

In this home we also insulated under the entire floor of the slab and up the side of it as well. This is commonly referred to as a thermal break, we have stopped or slowed the movement of thermal energy from moving through the basement floor. Along with this we place a 6-Mil vapor barrier under the concrete to stop the movement of water through the slab also. This eliminates the need for an energy hogging de-humdifier.

      When attempting to reach the standards for passive solar homes, all energy uses need to be considered. From the top to the bottom, no details is to small to overlook and in the case of the foundation,

it is no small detail.

 To finish off the foundation insulation, we simple cover it with a stucco and flash to top of it. Once again a little more work but in my opinion well worth the efforts.

Stay tuned

Tom Pittsley

tom.pittsley@nextsteplivinginc.com

Solar windows are really heating up

I did a little video of the windows in action over the coarse of a day. It was pretty impressive to see just how well they work. They video gives a better explanation of how the windows work as a system to not only capture and store the suns energy, but also how to control it as well.




I can't wait to see how well they work once the doors are installed.

Some other things that have been going on on the site is the interior framing, that was completed earlier this week. Along with installing the vapor barrier and insulation under the basement floor. Yes we not only insulate the exterior of the foundation but we also insulated under the basement floor and up along the sides of the concrete, eliminating a thermal break in the envelope of the building. Combining a highly insulated thermal envelope with air tight construction is what make a passive solar how possible. The higher the insulation level the lower the energy costs needed to control your indoor environment.

  This coming week we will be installing the solar chimney. What is a solar chimney? Stay tuned and find out.

Tom Pittsley
tom.pittsley@nextsteplivinginc.com

Our Solar windows are in !

The new solar windows for the house went in last week, just in time for the Green building tour this weekend. It was a tough week to say the least with 4 out of the 5 previous days filled with rain, around 4 inches. On Tuesday morning we finished installing the last of the SIP's roof panels, by Wednesday noon the roof was papered in and weather tight. At the end of the day on Friday, 19 of 21 the solar windows have been installed.

On Saturday they finally got some sun and started to show their stuff, as the windows reached around 110F by 4 in the afternoon. We left one window with the shade down fully to see how much of a difference the exterior solar shades make. The results were pretty impressive as the window with the shade down only reached 70F. Saturday was not exactly a warm day with a morning low of around 40F and a daytime high of only 63F, a slight breeze blew through the house as the other windows have not yet been installed. I can't wait to see how well they work once the house is buttoned up. Here are some IR images of the window at 4PM one with the shades up the other with the shade down all day.  These solar windows are unlike anything you have ever seen. The windows contain 4 layers of glazing, two cavities filled with argon gas, a couple of lowE surfaces and a 1-1/4" layer of clear gel. The gel acts as a thermal mass, storing the thermal energy within the window itself. The combination of glazing gives the window a U-value of .2 nearly 50% better than an energy star rated window for insulation value. Here is were it really differs, these windows have a Solar heat gain coefficient of .72. This means that 72 % of the solar energy is transferred through the outer layers of glass. This energy is then captured right at the point of entry into your home, within the gel. These windows are very heavy, about 250lbs. per unit, (26-1/2"x77-1/2") Each window contains about 170lbs of mass, this means for each degree above room temperature these windows go you have stored 170 Btu's of thermal energy. Raise the temperature to 110F like we did last Saturday and the thermal energy stored is 6,800 Btu's per unit. We have 13 windows that contain thermal mass within the window, this means we stored 88,400 Btu's of thermal energy in the windows of the home, over the course of one day. That is about equal to one gallon of oil burnt in an 80% efficient boiler or about one thermal of gas.       So, that's great right? but what about cooling? Notice the shades in the photo above. These shades are integrated right into the window frame and retract up into itself. The final arrangement of the controls is still being worked out but here is how they are designed to work at this time. The windows all have home run wiring back to the control panel, custom built for this project. The windows are then broken into groups according to location within the house. These groups are then controlled by a thermostat placed within the each zone. If the zone gets to warm the thermostat will send a signal and shut the shades. The really cool part is the remote control that gives the homeowner total control of each individual shade. When these shades are left closed the SHGC drops to .14 making this a energy saving window on the cooling side as well. I will post some more pictures and videos of the windows in action over the next few weeks. Stay tuned Tom Pittsley tom.pittsley@nextsteplivinginc.com

Lots of good stuff happened this week

Tuesday morning National Grid showed up to turn our power on, what a great day. After the last few weeks listening to the generator running it was nice to have have peace and quite. Well not exactly quite, with the compressor, saws and nail guns all day long but still much better than listening to the generator.

Some of the other things that happened this week.

I picked up the first 4 of our solar windows, man are they heavy. These windows have 4 layers of glass, with a 1" thick layer of clear gel encapsulated between 2 of them. Each of these 2'x6' windows weighs about 250 pounds, it's a good thing I have a one ton truck. These windows capture and store the suns energy within the gel layer and then radiates it into the house at night. They also have an exterior solar shade that retracts up into the head of the window that shuts the suns energy off when it's not needed. If you have the chance come by and see them for your self at the tour next weekend.
   
 We finished the last couple of wall panels on Monday and the rest of the week prepping for and installing the roof panels. Installed our triple 16" x 48' LVL ridge beam and got more than half the roof panels installed. only one week left until the Green building open house tour, next weekend and still a lot of work to do.

Tom Pittsley
tom.pittsley@nextsteplivinginc.com

Structural Insulated Panel (SIP's)

 What are SIP's and what do they do? Structural insulated panels, are a wall system that has been used for decades but has the misconception of costing more. If you take the cost of the materials alone, then yes they cost more if you add in the savings for labor and waste then the cost is about even. The panels themselves are comprised of expanded polystyrene insulation with two skins of Norboard laminated to them. Making an incredibly Strong and straight panel system that can be interlocked to create a highly insulated and air tight shell of the house. Let's take a typical stick frame wall system that is used to build virtually every home in this region. (New England) 2" x 6" wall framing with R-19 fiberglass batt insulation. When you factor in the thermal bridging of the wood framing the total R-value of the wall system is reduced to about R-13.7 ( ORNL whole wall calculator) SIP's give you an total wall R-value of about 22.25 nearly double that of a typical home. The other really big factor is the air tightness of the SIP's envelope, something that is essential when constructing a passive solar home.

     The process of prefabricating the panels reduces the time spent building the home and reduces labor costs by about 30% if designed properly. Notice I say if designed properly, I cannot stress enough how important proper design is essential to getting it right and reducing costs. One guy I know said he built a home with SIP's and hated it. i asked why and he said that cutting in the windows and doors was a very messy and time consuming process. I couldn't believe it, I had never heard on anyone fabricating the panels in the field. I wouldn't even consider doing this. While sometimes changes need to be made in the field, which is fairly simple, the thought of cutting out all the windows and doors would be daunting if done in the field. The panels we are using come from Branch River Plastics, a company located in N. Smithfield RI less than 50 miles from the job site and are totally fabricated to exacting dimensions. This makes installing the panels a breeze and virtually eliminates waste in the job site.
     No dumpster needed
   This is one of my personal goals when building a home. No dumpster! Yes we have some waste but with careful attention to detail this can be dramatically reduced and materials can be chosen that are easily recyclable. On our current project we will not be using a dumpster reducing operating costs even further.

When you combine the reduction in labor and waste, add the increase in insulation value and air tightness, SIP's are one of the best methods to build better homes. While this is just my opinion, it was formed through years of personal experience and research. I spent 18 years building with the old method and the last 10 using alternative materials and have found no other product that can increase your home efficiency without adding significantly to the costs of building better than SIP's.
 We are also using the SIP's for the roof of the house increasing the homes efficiency by another 30% of traditional methods. When all of the factors are combined you end up with a home that uses about 40-50% less energy to heat and cool than a traditionally built home. My last project built in Middleboro MA using a SIP's envelope along with passive solar design, efficient heating and cooling, that house heated last winter for only $341, my goal is to make this one even better. We will continue to track this homes performance long after the project is completed, to ensuring that we are reaching our goal of building the most efficient homes possible.

Stay tuned
Tom Pittsley
tom.pittsley@nextsteplivinginc.com

Some things make a home efficient

Some of the small things that have a big impact on energy savings
       
It all starts with the foundation

              There are tons of details that go into to making a home and it all starts with the foundation. Have you ever though about your foundation and how little insulation is has? Even new homes, built recently fall short in this area. Current building code requires that all foundations be insulated, the common practices used leaves something to be desired. Most homes built today have insulation on the exterior of the foundation but for some reason builders stop the insulation at grade. This creates a large area of your home that is subjected to the elements with almost no protection. Did you know that the concrete of your foundation only has an insulation value of about R-1? That's less than a window. One of the things we do is to insulate all the way up to the sill of the house. This results in your foundation being fully protected to an insulation value 12 times greater than traditional methods. Along with this we also insulate under the concrete floor of the basement and up the sides of the basement slab. These things combined have not only a big impact on your homes energy usage but also contributes greatly to the comfort within the home.

     I do know why traditional builds don't do this, it's simple. Costs! It isn't a huge cost but most builders are not willing to spend the extra time, money and effort to do this, but this is just one of the things that differentiate us from most builders. As a company we understand the implications that not doing this will have on your home and the costs to you the homeowner, having to heat and cool this home.

On to the framing next

Tom Pittsley
tom.pittsley@nextsteplivinginc.com