Posted by Derek Leavitt on Thu, Aug 06, 2009 @ 08:18 AM
Cool roofs are not tricky. They are what they claim to be: roofs
that are cool in temperature. So although the concept is simple, the
result is a very powerful tool for architects in the growing need and
desire for greener buildings.
1. The Basics
Cool roofs stay cool by doing two things:
a) reflecting heat from the sun (called solar reflectance).
b) quickly re-emitting any heat that is absorbed (called thermal emittance).
In essence, the goal of a cool roof is to reduce the amount of heat entering the building. As
seen in the diagram below, these two properties, solar reflectance and
thermal emittance are what determine if a roof is technically cool.
Diagram courtesy of the lovely people at the Cool Roof Rating Council.
2. Cool Roofs Are Not A New Idea
There's a lot of technical jargon you can get into when it
comes to cool roofs. Leave that to us architects. In principal, cool
roofs work because:
Get it? White roofs absorb less heat than dark-colored roofs. A cool roof only absorbs 10-15 percent of the sun's heat versus 90 percent heat absorption for a traditional dark roof.
The
beauty of cool roofs is that they're a low-tech concept. Long before
the days of electricity and air conditioning, warm-climate areas used
light colors in their buildings to reduce heat gain. I think I even
wrote something about this last year called Environmental Architecture in Greece.
In Santorini, Greece, cool roofs (and walls) are not a new idea.
However, since people don't always want white roofs, some smart
scientist types have figured out a way to have cool roofs with
darker colors by utilizing special highly reflective
coatings. Cool roofs are versatile, coming in all types of materials that can be applied to a home just as easily as to an office or industrial building.
3. Cost
Inevitably, the first question we get after we describe a green
feature to a client is "That's great, but is it more expensive?" Thankfully, for
cool roofs, the answer is "not really." The added cost for a cool roof
can be as little as 15 percent. This minor increase is far outweighed by
the projected 20 percent or more savings in air conditioning cost (source). Besides, knowing you have a cool roof and are helping the environment will make you feel warm and fuzzy
inside.
Compared to other green building features with high upfront costs, such as solar panels, cool roofs are an affordable option.
4. It's Not Just About You
Don't be selfish when selecting a new roof. Having
a hot roof not only increases your cooling costs, it also affects the world around you through an ugly phenomenon called heat island effect.
Diagram of Urban Heat Island Effect, courtesy of Lawrence Berkeley National Laboratory
Heat
island effect occurs as result of the numerous heat-absorbing surfaces
that cities contain such as dark colored roofs, streets and seas of
parking lots. This effect overheats urban areas, increasing the demand for air conditioning and electricity. Another not-so-fun aspect of heat island effect is that it's known to increase smog
formation.
5. For Remodels Too
Whereas many green building features are better suited for new construction or extensive remodels, cool roofs are a viable option for any remodel or simple re-roofing.
On our recent remodel of the Fashion Square Car Wash, we specified a cool roof to reduce the air conditioning loads and heat island effect from the surrounding paved areas.
The re-roofing of the Fashion Square Car Wash started out looking very similar to a typical roof. So far, not very cool.
That's a little better.
Now there's a cool roof.So in this case, the roofing was pretty standard, but in the end it was covered with a white coating to increase its reflectivity.
6. Location, Location Location
There is a fair amount of debate
as to whether cool roofs are beneficial in all climate zones. For us here in
Los Angeles and other warm climates (hey Texas, Nevada and Arizona), it's a
no-brainer:
cool roofs work. The worry in cooler climates is that cool
roofs don't allow for thermal gain in the winter. The good news is that
there are numerous studies that have shown that cool roofs are effective in just about any climate.
Potential net energy savings from changing roof reflectivity. Savings are measured in dollars. Note that the net savings are the savings of cooling energy use less the penalties of heating energy use. Image courtesy of the Heat Island Group.
If you have any thoughts on cool roofs, feel free to leave a comment or send us a fancy form message.
Posted by Derek Leavitt on Tue, Mar 17, 2009 @ 11:33 AM
So, is now a good time to start a building project? While it is a scary time, there are opportunities abound for those that have the courage and means. I am no fortune teller, but I can dish out a bit of what I've heard and experienced in the last few months. Of course I'll also throw in some invaluable gut intuition.
The Bad
- Banks - Lending is tight. Really tight. As a banker recently told me, "our current appetite for lending is small." He went on to say that the easiest type of loan to get these days is for an owner occupied building. That is their way of saying if you're building it for yourself to occupy (a home, remodel or commercial building) and you qualify, you may have some of their money.
- Uncertainty - The development attitude in the recent boom was build it and they will come. This is not the case anymore. You have to be careful what you build, for whom, and at what cost.
The Good
- Cheap Land - The price of land seems to be back to where it needs to be to make development projects work again. People assumed that the ever escalating price of new homes and condos was all developer greed. It was not. High land prices and construction costs dictated high sales prices.
- Foreclosures - OK, foreclosures are bad. Someone loses, banks fail. This is one of the main reasons we got into this mess, right? I get it. Now for the bright side. Foreclosures can be opportunities. The cheap real estate they offer allows for new opportunities - a quick condo flip, land for your new home, the chance to develop a small project, etc.
- Cheaper Construction - The price of materials and labor have fallen due to demand reductions. Almost all material prices have been in decline since the summer of '08. Contractors are hurting. Less work for them means they will take on projects for smaller overhead and profit percentages. Quality contractors are also taking on smaller jobs that they wouldn't touch a few years back.
- Cheaper Soft Costs - It pains me as I write this, but the bad market has also lowered the costs of architects, engineers and all the other people that get you to the point of construction and beyond. Why? They are also hurting.
- Faster Permitting - We do a fair amount of architecture work in Los Angeles, and the difference at City Hall these days is astounding. What used to be a four hour wait to submit for plan check is now a four minute wait. In our experience, their processing times are much faster as well.
- Time - Time is the typically bane of the architect and owner's existence. Building projects take time. They have to be designed, coordinated with consultants, documented and permitted. All this adds up to a long process that can be quite burdensome. Now, however, this time factor can help with some of our major negatives. Banks will start lending again. The market will recover. So when you think of a building project, think about the time involved. Many projects take about a year to get to permit/construction start (when you need that construction loan), then the construction can take another year (when you move in or need those prospective buyers.) So ask yourself where you think things will be in one to two years.
- Emerging Trends - Major slowdowns are often times of reflection and change. This is very true in the building biz. Of late, I've seen a strong desire for smaller, more efficient, green buildings. This trend comes both from awareness of climate change and our financial need to do more with less. I like this trend and think that it'll bring about some very innovative and evolved projects.
Do you have any thoughts on this? Questions?
Posted by Derek Leavitt on Wed, Mar 11, 2009 @ 12:00 PM
One of the major components the energy efficiency of any building is insulation. Insulation is critical to maintaining comfortable indoor temperatures by either keeping the heat in or out of a building.
Green Insulation
As sustainability gains momentum in the building industry, new products are available that rethink insulation. One of these is recycled denim insulation. Yes, old jeans. One of the leading manufactures of this green product is UltraTouch.
It even looks like your old jeans. (images from UltraTouch & Victor Insulation)
Don't Eat the Pink Stuff
UltraTouch Natural Cotton Fiber Insulation is targeted as a replacement for traditional fiberglass insulation - the typically yellow or pink soft looking stuff you see between the studs during construction. Yes, you're probably also picturing the pink panther. If you haven't had the pleasure of handling traditional fiberglass insulation, don't. It's not pleasant stuff to to touch (itchy) or breath (can cause respiratory problems). I definitely wouldn't wear pants made of the stuff. UltraTouch on the other hand is made of safe, easy to handle, recycled denim.
UltraTouch comes in rolls and is easily installed.
Product Info
So aside from this obvious point that it the product is safer for people to install, here are a few other interesting factoids:
- The insulation is 85% post industrial recycled fibers.
- Has acoustic ratings approximately 30% better than traditional insulation. Less outside or neighborly noise.
- The cotton fibers are treated for fire resistance - Class A rating.
- No VOC concerns - those little particles you don't want to breath.
- Good mold resistance.
- Obviously helps with LEED certification points.
Cost
A common question, as with most green products, is does it cost more? Well, yes, it does. How much more depends on the size of your project and the construction market. However, the short and long term benefits of this product far outweigh the upfront costs.
At Modative, we are now specifying this or similar products instead of traditional fiberglass insulation. If you are concerned about the cost, we're happy to help you compare the cost of this green product to traditional insulation.
Posted by Derek Leavitt on Thu, Oct 02, 2008 @ 09:40 AM
I just returned from a vacation in the Greek islands and discovered some amazing historic examples of designing for the environment. The trip began on some of the Cyclades islands: Paros, Ios, and the better known Santorini. These islands contain the type of architecture one often pictures when they think of the Greek Islands; white painted flat roofed structures with minimal blue trim. These collections of white boxes stand out beautifully against the often barren brown landscape and deep blue color of the Mediterranean sea. This clean and practical style stuck with me as almost modern in appearance. Created only for pure function. No decoration necessary.
The Cyclades Islands: Santorini
This style that became so common among the Cyclades islands changed dramatically when we reached our final destination of Samos located in the lesser known North Aegean island chain. Samos, less than 80 miles away from the Cyclades islands contained structures with pitched tile roofs and much less white paint.
The North Aegean Islands: Samos
Intrigued by this dramatic difference in the architecture of these islands I asked a tour guide/ archeologist for an explanation. She explained that the reasons for the difference was simply climate.
The Cyclades islands were very dry, hot islands, so the buildings had flat roofs that could collect the minimal rainwater they received for reuse. This is especially important when you are on a small island with no other viable sources of water. These buildings were also all painted white to reflect rather than absorb the summer sun. The structures also had small windows to keep the heat out. Time inside these dark interiors is minimized by spending time on outdoor shaded patios.
Designed for Dry: Santorini
Samos on the other-hand has a much higher annual rainfall, which was evident by the abundant vegetation on the island and the fact that it rained most the time we were there. This is why the roofs are pitched; to get the rain away from the structures. This milder climate also explains why the windows were larger and the buildings were not all white.
Designed for Rain: Samos
This beauty of this contrast is that it shows how buildings had to be designed to their environments in the days before electricity and easy transportation. The buildings were not designed to a particular style to maintain a common appearance but to their particular microclimate. I love the sustainability of these simple design moves. Although the process of making our build environment more "green" involves utilizing innovative technologies, these simple lessons from the past have much to offer the design community as to how to move sustainability forward.
Posted by Derek Leavitt on Fri, Jan 11, 2008 @ 08:57 AM
Having our office a block away from the historic Helms Bakery complex in Culver City/LA means hardly a day goes by without walking past its parking lot which features a solar array shading device. Utilizing photovoltaics (solar panels) to shade parking lots is a great idea to begin with. This device, however, built in 2003, takes it a step further by having the panels also provide power for an electric car charging station.
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Imagine arriving at work daily to have your car charged up for free in an environmentally friendly way - seems perfect right? The only problem is that electric cars, for the most part, are nowhere to be found. The movie, "Who Killed the Electric Car?", clearly illustrates some of the circumstances behind the electric cars' demise in the 1990's. As the green movement grows, hopefully the electric car and its numerous possibilities will be revived.
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As I walked by the solar charging station a few days ago I noticed a car parked in one of the charging spaces that clearly illustrated this problem.
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