Green Dream
Rooftop greenery guards against water damage and bland meals

The Green Dream: Vertical Garden John B. Carnett, PopSci’s staff photographer, is using the latest green technology to build his dream home. Follow his progress in each issue, and visit popsci.com/greendream for tips, videos of the build, and John’s blog. Peter Bollinger

What’s a green home without actual greenery? I wanted my eco-friendly house to feel more connected to nature, so I turned the flat stretches of roof into gardens. Rooftop flora is not only scenic, but it can also protect a home against temperature extremes, absorb carbon dioxide, and triple the life span of a roof.

The first thing to know about building a green oasis on top of your home is that dirt is heavy, and it gets even heavier when wet. Before I did anything, I consulted an engineer to figure out the maximum load my roof could handle. Standard green roofs hold four inches of soil and weigh 15 to 20 pounds per square foot. The deeper the soil, the more options for planting, but four inches is plenty of depth to grow a wide range of flowers and herbs.

The next step was prepping the roof for proper drainage and waterproofing. First I put down a tapered layer of insulation to channel excess water into storage tanks on the ground. Over that goes a layer of deck paneling secured to the roof with foam adhesive. These panels provide a hard surface for the garden and keep wayward roots from reaching the roof. The final layer is a special weatherproofing rubber.

With the roof fully protected, I was ready to add soil. Some people toss dirt over the entire roof, but I opted to load it into a patchwork of trays. Containers are easier to install and easier to remove should the roof require repairs. Many companies deliver trays fully loaded with lightweight soil specially designed for green roofs and mature plants. Although these are convenient, some cost up to $20 per square foot. By buying the trays and soil in bulk and loading up the trays myself, I was able to reduce the cost to about $5.50 per square foot.

The fun part—actually planting things—starts this spring. Look for all the details on that in the March issue.

Next month: Save copper with wireless light switches

The Specs

House: 3,500-square-foot, four-bedroom contemporary
Location: Greenwich, N.Y.
Project: Building a green roof
Cost of materials: $15.50 per square foot for entire project
Time to install: Six days
Eco-advantage: Creates wildlife habitats, absorbs CO2, insulates roof

What's Inside: A Green Roof:  Peter Bollinger

  • SOIL A four-inch bed of lightweight dirt is plenty to support herbs and wildflowers.
  • RUBBER Sheets of thermal polymer called TPO protect against temperature extremes and UV damage.
  • ROOF BOARD A fiberglass mat creates a hard, deck-like surface. It also thwarts mold and wayward roots.
  • ADHESIVE Sticky foam secures the roof board to the insulating panel below.
  • TAPERED INSULATION A layer of insulation installed at a slight pitch helps drain any excess water.
  • ROOF PANEL The garden’s foundation is an 11-inch-thick roof panel made of recycled expanded polystyrene that can support up to 70 pounds per square foot.

Already Have a Home?

Four Ways to Green Up Your Greenery

  • E-YARD GEAR Nearly 17 million gallons of gas are spilled annually refilling yard equipment. Ryobi’s new battery-powered chainsaw, string trimmer, leaf blower and hedge trimmer recharge in an hour, without a wasted drop of fuel. Plus, there’s no worrying about changing spark plugs. Available this month.
    $100–$120; ryobitools.com
  • ECO-INSECTICIDE Based on plant oils that protect against insects, this natural insecticide from EcoSMART won’t harm people or pets. Spread the granules, which are infused with thyme, eugenol and sesame oil, over the lawn to kill more than 100 kinds of insects, including ants and mosquitoes. Available this spring.
    $13/10-pound bag; ecosmart.com
  • A REEL MOWER
    Gas-free mowers struggle through tall grass and twigs. The Fiskar Momentum uses a 6.9-inch-wide cutting wheel with 4.5-millimeter-thick blades to generate twice as much power as other reel mowers while requiring 30 percent less force to push. Lift the blades up to four inches with the touch of a button. Available this month.
    $220; fiskars.com
  • SMART WATERING
    Dial in specifics about your lawn’s environment, like soil type, climate and water requirements, and the Intelli-Sense irrigation controller calaculates an efficient watering schedule. The system uses daily updates from NOAA satellites and other weather data to trim your water use by up to 45 percent.
    Starting at $325; toro.com

John B. Carnett, PopSci's staff photographer, is using the latest green technology to build his dream home. Follow along as the project progresses on his Green Dream blog: popsci.com/green-dream

Want to learn more about the environment, solar energy, sustainability, and more? Subscribe to Popular Science today, for less than $1 per issue!

16 Comments

Question on winter and freezing temperatures. If you have just 4 inches - what happens during the winter, the ground will freeze and aren't you now under a block of ice? Does that still have an r value or can you rapidly grow some rye grass about 3 months before the snow so that you can have a bed of "hay/straw"? You then till that in come Spring. But then 4 inches, you can't really till either. Have you thought about going deeper and what does that do to the load on the supports? Oh and careful mowing...one wrong move and you'll walk off the roof with the lawnmower in tow.

It's incredible how people is going more and more for the Green way of life.

Amazing post BTW.

UsdBot | Forex Robot

I would even consider installing another fail-safe layer below the waterproofing just in case the water proofing fails. Some sort of a drip pan would work. The last you would want is water damage to the livable area below. But wonderful design - nice job

www.waterdamageout.com
www.purocleanhomerescue.com

For those of you working with kids and wanting to get them excited about plants and gardening, Have them grow a TickleMe Plant before installing your roof top garden. This is the plant that will close its leaves and lower its branches when tickled. Our school (k-12) has found it a great way to excite kids about nature. If you haven't grown a TickleMe Plant yet, search TickleMe Plant to see a video of the plant and get your supplies. Its the only houseplant that moves when you tickle it.

www.sensitiveplant.com

I am interested in knowing how significant the support structure changes would be to enable your builds roof to support enough soil depth for a more traditional " Kitchen Garden " ? I live in Northern Michigan ( TC ) with a climate very similar to yours. An elevated garden eliminates some of the " pest " control issues.

It would be fun to see ideas for adding irrigation from a gravity fed ( watertower ? ) source. Possbly supplied by wind pump or rain collection. Automation is a wonderful thing and mother nature invented it balancing vegetations needs against available resources.

How are you heating the house ?

Being in the Real Estate industry I am constantly surrounded by talk of the "green movement". This of course is really cool!
www.massrealestatenews.com

Have a good start.
Have a good end.
www.eluxuryin.com/

Sure, the green actions are imperative to implement! The problem of environmental protection does make us headache. Propaganda is not enough. We should make some contribution to the green dreams in our minds. For example to advocate green consumption, to promote the green industry, construction and eco-home. The idea of installing a rooftop garden here is constructive and creative. I would like to have a try and am looking forward to March issue.
http://www.louisvuittonbagmall.com/Louis-Vuitton-category-1-b0.html Louis Vuitton

Reading all this makes me want to go and put a vertical garden on the top of my apartment building. It seems like a smart way to go green, but it’s probably really time consuming as well as expensive too.

www.360rugs.com

The concept of green roofing is so fascinating, but in realistically, it can be very expensive. Personally, when greening my home I prefer to use polyurethane foam insulation. It’s so much greener than fiberglass and much cheaper than green roofing.

Reading all this makes me want to go and put a vertical garden on the top of my apartment building. It seems like a smart way to go green, but it’s probably really time consuming as well as expensive too.
www.promdresspicture.com

لأولئك منكم العمل مع الاطفال والرغبة في الحصول عليها متحمسون النباتات والبستنة ، ويكون لهم زراعة النباتات الدغدغة لي قبل تثبيت الحديقة الخاصة بك سقف أعلى. وهذا هو المصنع الذي سيغلق أوراقها وأغصانها أقل عندما مدغدغ. وقد وجدت مدرستنا أنها طريقة رائعة لإثارة الاطفال عن الطبيعة. إذا لم تكن قد نمت وأنا الدغدغة النبات حتى الآن ، والبحث دغدغة النبات لرؤية شريط فيديو للمصنع والحصول على اللوازم الخاصة بك. في محطة البيت الوحيد الذي يتحرك عند دغدغة ذلك.
http://www.autonewstoday.net

Läst allt detta gör att jag vill gå och lägga en vertikal trädgård på toppen av min lägenhet byggnad. Det verkar vara en smart väg att gå grönt, men det är nog riktigt tidskrävande och dyrt också.

www.CARS-WEB.ORG
www.CARZ-INFO.COM
www.freshcarnews.org
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Pour ceux d'entre vous travailler avec les enfants et le désir de les enthousiasmer sur les plantes et le jardinage, les faire pousser une plante TickleMe avant d'installer votre jardin sur le toit. C'est l'usine qui fermera ses feuilles et ses branches inférieures lorsque chatouillait. Notre école (k-12) a trouvé un excellent moyen pour exciter les enfants sur la nature. Si vous n'avez pas cultivé une usine TickleMe encore, de recherche TickleMe usine pour voir une vidéo de l'usine et obtenir vos fournitures. C'est la plante d'intérieur que ce qui bouge lorsque vous chatouiller.

www.autocar-today.com
www.auto-carz.net
www.AUTOCARZ.ORG
www.thaicarnews.com

Vorrei anche prendere in considerazione l'installazione di un altro strato di fail-safe sotto l'impermeabilizzazione nel caso in cui l'impermeabilizzazione non riesce. Una sorta di una ghiotta avrebbe funzionato. L'ultimo che si vorrebbe è un danno acqua alla superficie abitabile di seguito. Ma meraviglioso design - buon lavoro

www.wedding2know.com
www.weddingplusz.com
www.thaicarnews.com


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