We have started to explore larger projects with our development company in Philadelphia that include shared off-street parking lots with a common driveway. This provides a new opportunity to explore more sustainable pavement options than the traditional blacktop used in most projects. Part of our research, as always, is devoted to finding the best mix of sustainability and cost so that we, and others like us, can actually have a chance of implementing something new on a for-profit project.

First, a bit of quick background on how Philadelaphia’s Water Department is actually encouraging projects to use permeable pavement in larger projects. In Philly, the city requires projects that exceed 15,000 square feet of area to develop an approved Stormwater Management Plan. Typically this involves large underground detention basins and extensive piping. There is also a lengthy design process typically associated with the Philadelphia Water Department.

Fortunately, the PWD provides incentives to builders to fast track their design and approval process for stormwater management if they can satisfy the needs via “green” methods. This typically always includes some type of pervious paving surface where impermeable would typically be installed and a method of delaying roof runoff from entering the city sewers (think green roofs or giant rain barrels).  Yea Philly!

OK, now on to the different options available in pervious surfaces that you can drive a car or even a large truck over. We’ll cover the main types that we have run across and you can tell us what we’ve missed in the comments. All of these systems are installed in a similar fashion. There is often a bit more excavation and up to a foot of crushed stone or gravel installed prior to the paving surface in order to help facilitate collection and storage of large rainfalls without the surface experiencing flooding. Simple, smart and effective. Read on and enjoy my rating system.

Porous Asphalt (Blacktop)

That's a fancy stream of water!

Porous Asphalt, or Blacktop as the kids say, is one of the more popular options out there as it seems to be the most cost effective and widely accepted. After all, it looks pretty much like normal blacktop and asphalt is king for most of our roads and parking lots.

Cost – $
Maintenance – Lots
Porosity – ~176″/hour
Ability to Grow “Green Things” – 0 out of 5
Overall Sustainaearthgreenfriendliness – D+

The Asphalt starts out strong with low cost and effective porosity, but quickly loses points for requiring a lot of maintenance, zero ability to grow anything, being nasty and a strong contributor to the urban heat island effect. Don’t get us wrong, it’s much better than standard asphalt. We’d just prefer one of the other alternatives a bit more for smaller projects that don’t include thousands of miles of roadways.

The maintenance we are talking about is a biannual cleaning with a giant commercial vacuum type device to keep the voids in the blacktop from getting clogged over time. Sweeping or pressure washing won’t do and may only contribute further to premature clogging. Check out the National Asphalt Pavement Association for more info.

Pervious Concrete

Oooooooooh!

Pervious Concrete is the same concept as porous asphalt, except it’s concrete. It’s very easy to order and have installed by a skilled flatwork contractor, even if they have never used it before as it is basically normal concrete with no “fines” in it. This is how it remains open to water infiltration. A benefit over asphalt is that is will result in a much lighter color that will not contribute to the urban heat island effect as much. It is still concrete though and comes with the carbon footprint associated with concrete if you’re counting carbon points on your project. A bit costlier to have installed than porous asphalt, it is a choice we prefer if options are limited.

Cost – $$
Maintenance – Lots
Porosity – ~480″/hour
Ability to Grow “Green Things” – 0 out of 5
Overall Sustainaearthgreenfriendliness – C

One way to reduce your carbon footprint with any concrete order is to insist on local or even reclaimed aggregates and push for the highest amount of Fly Ash and/or Slag which are both reclaimed waste products. Pervious Concrete also requires the same biannual sucking that porous asphalt recommends. Check out PerviousPavement.org for more info on Pervious Concrete.

Pervious Block Pavers

Most commonly seen permeable concrete paver

There are many different types of Pervious Block Pavers popping up on the market now that the concept of saving the earth is gaining popularity again. The most commonly seen permeable paver is shown to the left and creates a hexagonal shape of concrete around a central pocket where grasses can be planted or simple gravel can be filled in.

Cost – $$$
Maintenance – Some
Porosity – Varies
Ability to Grow “Green Things” – 3 out of 5
Overall Sustainaearthgreenfriendliness – B+

That tire is really working up a sweat.

Since the popularity of this interlocking concrete paver had increase, more varieties have hit the market that look more like traditional pavers. An example is shown to the right. These pavers have less open area that is usually created either at the corners or by spacing the pavers on all sides to allow for infiltration. This type of paver can not grow anything in the voids, but is typically filled with gravel. It’s a nice option for those that want the traditional paver look with boosted functionality.

Tbe biggest deterrent to these types of pavers is the cost. Not only are the pavers themselves pricey, but the cost of install is typically much higher than the other varieties of permeable paving due to having to lay individual, small blocks by hand. There can be some maintenance with these pavers as they may individually settle or become misplaced after some use. They may also be damaged easier than a uniform pavement by snow removal in the winter. There are too many suppliers of these products for me to point to one source, but Google can help you out if interested in more info.

Drivable Grass

Drivable Grass with grass, sand, gravel & mulch filler

Drivable Grass is a specific product manufactured by the Soil Retention company. It’s kind of a unique product that we recently stumbled across at Greenbuild that I felt deserved it’s own category. The product melds a bit of the benefits of the other products into one system.

For starters, is comes in 2′ x 2′ mats that are much more affordable to have installed than the individual pavers. It also has a much larger exposed area (61%) for greater infiltration and more room to grow grass or ground cover in if desired. Also, unlike the traditional hexagon turf pavers, this system does not isolate the plant material into individual pockets. This allows the plantings to remain cooler and receive more uniform watering. These benefits result in a greener parking surface than most of the alternative plantable systems.

Cost – $$
Maintenance – Very Little
Porosity – I couldn’t find a spec. Sorry.
Ability to Grow “Green Things” – 4 out of 5
Overall Sustainaearthgreenfriendliness – A

Currently, this is our top choice to use in a few of the sites we are looking to develop in Philly that have shared parking areas. It looks like the cost will be less than permeable concrete and we will get the added benefit of creating a green space in the parking lot that requires much less maintenance than other systems which will reduce the HOA fees for the home owners. All good things so far.

Plastic Grid Systems

Yes, you can drive on these plastic cup things

Cost – $$
Maintenance – Very Little
Porosity – Lots
Ability to Grow “Green Things” – 5 out of 5
Overall Sustainaearthgreenfriendliness – A

Last but not least are the plastic grid varieties of permeable paving systems. Some of these get extra points for being made of recycled plastic and being fully recyclable themselves. We have done the least research on these systems, but the install seems straightforward and it can result in a fully sodded surface if desired. The main issue we saw was that it is recommended for light or occasional use parking lots if you want to maintain the grass on the site. If anyone has any experience with this type of product, please speak up in the comments.

Conclusion. That’s all I have. Contribute below.

We just got back from Greenbuild in Chicago and are a little more tired than expected. That is probably because we had to lug this sweet piece of hardware back with us . . .

That’s right, the 100k Project actually won the USGBC’s national award for LEED for Homes Project of the Year. We are very grateful for this recognition and hope to make it the first of many. We also hope to parlay this win into an actual speaking engagement at Greenbuild next year.

We are thankful (a fitting emotion this time of year) for everyone who worked on this project. We would particularly like to thank ISA for their architectural expertise and complete buy in to our crazy ideas and Magrann Associates for getting us through the LEED process and making sure we did what we needed to do for that Platinum rating. We also want to thank all of you out there following along, commenting, suggesting, critiquing, encouraging and just generally making us feel like this project was worth doing.

We will post more info on this award as it comes out, but for now, you can see the profile that was posted at Greenbuild in PDF form if you are interested. Thanks again and stay tuned. This is still just the beginning.

The wait is finally over. The LEED for Homes Platinum Certification for both homes in the 100k project has been received. After a variety of delays including, most notoriously, the replacement of an incorrect bath exhaust fan, we have finally received official notice from the USGBC that both the 100k and (poorly named) 120k have acheived the highest status in the LEED for Homes rating scale.

We see this achievement as official proof that green building can be done for less. The 100k House reached this goal for less than $100 per square foot in hard construction costs and has proven itself to be a stylish, comfortable place to live (just ask Courtney). While we have slightly increased our construction budget for future homes, we see this success as a key foundation of our long term goals.

Did we make mistakes? Of course. Are there things we intend to do better/differently in the future? Naturally. But, we are still proud of our first project and would like to thank all of those who helped us make it a reality.

This milestone does not mark the end of the 100k project. We are currently gathering utility data and other long term project results that we will be sharing in the near future. We continue to learn from this project as we move forward with our construction efforts, and we will use the lessons to constantly improve our building methods.

We would like to extend a special thank you to MaGrann for guiding us through our first LEED for Homes process. The paperwork was occasionally painful and the process wasn’t exactly smooth, but they stuck with it and helped get these homes the recognition they deserve. Hopefully, our next LEED project (the Skinny Project) will progress more smoothly with equally impressive results.

Questions and congratulations will be heard in the comments.

I’m not sure how we’ve forgotten to post on the Construction Waste Management done for LEED for Homes on the 100K House project? Let’s do a little recap here for all those interested. First we will briefly go over the LEED requirements and credits, and then we’ll take a look at the methods we used and the results.

LEED for Homes Waste Management Requirements

Prerequisites – Construction Waste Management Planning

1. Investigate and document local options for waste diversion from landfills including cardboard packaging and beverage containers the end up on the site.
2. Document the diversion rate for construction waste. Separate demo from new construction portions of a project if applicable.

Credits – Construction Waste Reduction

Reduce or divert waste from landfills to a level below the industry norm via either of the two options below:

1. Reduce construction waste – Generate 2.5 pounds (0.016 cubic yards) or less of net waste per square foot of conditioned floor area. See chart below for score.
2. Increase waste diversion – Divert 25% or more of the total materials taken off the construction site from landfills. See chart below for score.

100K House Construction Waste Management Results

We decided to go with the second method of verifying our diversion rate in order to gain our points in this section of LEED for Homes. It’s actually quite easy in Philly to do this thanks to a company conveniently named Construction Waste Management. All of the charts and pics that follow in this post are courtesy of CWM’s final report to us.

The beauty of this company and others like it across the country is that nothing changes on the site for the contractors. They deliver a standard dumpster to your site, you throw your trash it in like normal and they come take it away when it’s full. They then take the cans to an offsite location where they sort all of the material that can be recycled before sending off the remaining trash to the landfill. They even send you a lovely record of all of you dumpsters used per project which is exactly what the LEED folks are looking for in terms of verification for these points.

Here is our summary chart from Construction Waste Management:

This chart represents the aggregate total from three cans we used on the 100K House project. Since we diverted over 75% of our waste from landfils, we earned 2.5 points for this section in LEED. That’s just half a point from the maximum 3.0 points that can be earned for diverting over 88% of your waste. Not bad and I think a full point higher than we accounted for in our initial LEED checklist.

Construction Waste Management Images

To finish up this post, we thought you guys and gals might enjoy a more detailed look into the Construction Waste Management company’s operations. There are many similar companies sprouting up all over the country and their rates are often lower than traditional waste companies as they have an extra stream of income from selling the recycled materials they claim from construction sites. So it’s greener and cheaper! That looks nice in print.

Example of a dumpster being emptied for sorting offsite at CWM

Wood is sorted and made into mulch


Plastic is baled and sent to a recycling center


Steel is stockpiled and then shredded


Cardboard is recovered, baled and sent off to be recycled


Drywall scraps are pulverized

As we near the completion of the 100K House project, we need to start thinking about our landscape design. As always we have to consider LEED reqs and points, modern design and budget. We are talking to a few local landscape designers in the area interested in the project. Due to budget and time constraints, we may not be able to go all out on design this time, but hope to make continual improvements going forward.

To keep things simple, I’ve compiled one list of only the points we are going after in the Sustainable Sites section of the LEED for Homes rating system. The fact that our site is so small makes a lot of these items pretty easy to accomplish. At the same time, the erosion controls are a bit out of place and possibly the only thing on the entire LEED checklist that we might not do if it weren’t for LEED.

LEED Landscaping Goals

Prerequisite: No Invasive Plants

1. Add mulch or soil amendments as appropriate.
2. All compacted soil must be tilled to at least 6 inches.
3. Do not use any conventional turf (technically less than 20%).
4. All plants must be drought tolerant.
5. If sidewalks are replaced, use white or gray concrete or any material with a solar reflectance index (SRI) of at least 29.
6. Design lot to be 100% permeable (no hardscaping). This includes permeable paving and even hardscaping that is designed to direct all runoff toward a permanent infiltration feature (on-site rain garden or rainwater cistern).
7. Plant one tree or four f-gallon shrubs to reduce erosion.
8. Install rainwater cistern to manage runoff from the roof.

Again, these are only the goals for our project. There are other ways to get points in this section of LEED that I did not go into here.

As far as the design, we will most likely have a very simple layout that contains a lot of decorative gravel rather than traditional turf. We are using our favorite residential landscape designer in the US as inspiration – rosenlof/lucas. We spoke to them a few times, but the distance makes it difficult for us to work with them both logistically and philosophically. The image above is from their site. It’s well work the visit to their site to get inspiration for modern and affordable landscape design.

In an interview a few weeks ago I was asked what our premium was for building LEED Platinum. The reporter had done some research and found that the highest level of LEED for Homes usually carried a 15-20% markup and wanted to know what the added cost was for our project. It was a difficult question since we don’t have a non-LEED version of the house with which to compare, but eventually I said, “Um . . . I guess . . . negative 5%” (an estimation of my interview articulacy). I went on to explain that, with the average new home built in Philadelphia coming in at a minimum of $125 per square foot in hard construction costs and our, admittedly more sparse, home hitting $100 psf, I figured that number was defensible.

The next question of course is why? Why do production home builders and established developers, people who have been building homes for many years, have to spend 15% more to get to LEED Platinum while us rookies are getting there at a discount? It was a question I had no concise answer to until a few days ago when an acquaintance, who wishes to remain anonymous, gave me a piece of her grandmother’s wisdom in explanation . . . “It is because they’re polishing a turd.”

OK, so it’s a bit harsh. Turd is, maybe, an unnecessarily rude word to use to describe what are often pretty nice homes, but the concept is sound. Most of the builders and developers reporting high premiums for pursuing LEED are still trying to build the exact same home they have always built. They are simply adding features to make that same house energy efficient, healthy and sustainable. This addition gets expensive.

Builders, successful ones anyway, often have a basic home that they build over and over. They know how it goes together. They can build it quickly and inexpensively, and most importantly, they know it will sell. When they are suddenly faced with the need to “go green,” they are understandably reluctant to make significant changes to the design of their proven house. Location, interior fixtures, numbers of bedrooms and bathrooms, square footage and window placement are all tested and successful specs. The familiar methods of construction they use are easy for them to estimate and well known to every sub-contractor and laborer on the site. There is, in their minds, less management and less risk.

So, they polish the turd. Rather than redesign the house that has been successful for them in the past, they add solar panels, geothermal systems, high end interior fixtures, extra insulation and other green features. The house gets greener. It gets certified, but it also increases significantly in cost. Since the features are add-ons and extras, the price rises as each one is tacked on.

To avoid these extra costs, one must start the home design process with affordability and sustainability factored into every decision. One simply can’t, in most instances, build the same home in the same place using the same techniques and expect to accomplish those goals. For example, one can’t:

• build on arable land 20 miles from the nearest amenities.
• build a 5000 square foot single family home.
• have more windows than walls, particularly on the north and west side.
• add a garage.
• have giant spa tubs in each bathroom.

And so on . . . Of course, one can do some of these things and still get a LEED certification, but it is going to take some expensive turd polish.

Well, all that said, I am nothing without the wisdom of your comments so . . . What do you think is the single biggest stumbling block for established builders trying to move toward affordable green? Why is there a premium on LEED? What process would you recommend to a developer trying to make the change to sustainable building? Who would you suggest the developer involve?

My apologies to the linguistically sensitive among you for the prevalence of a certain scatological aphorism throughout this post. You may scold me for that in the comments as well.

In preparation for our open house this weekend, I created a quick document with a bulleted list of all of the LEED for Homes points we are going after to achieve LEED Platinum in the 100K House. It is basic, but I thought I’d post it here since we haven’t spoken of the checklist in a while. Feel free to ask questions in the comments and I’ll try to address them as best I can.

ID Innovation and Design Process – 7 Points

1. Integrated Project Team 1
2. Design Charrette 1
3. 3rd Party Durability Management Verification 3
4. Innovative Design Credits

• Education & Awareness – Going above & beyond reqs 1
• Electricity monitor / phantom load prevention system 1

LL Location and Linkages – 10 Points

1. Site Selection 2
2. Preferred Locations
   • Infill lot 2
   • Previously Developed 1
3. Existing Infrastructure 1
4. Outstanding Community Resources / Transit 3
5. Access to Open Space 1

1. Very High Efficiency Fixtures & Fittings 6

EA Energy and Atmosphere – 23 Points

1. Exceptional Energy Performance (HERS) 23
2. Efficient Hot Water Distribution 2
3. Pipe Insulation 1
4. Appropriate HVAC Refrigerants 1

MR Materials and Resources – 9.5 Points

1. Off-site SIP Fabrication 4
2. Environmentally Preferable Products 4.5
3. Construction Waste Reduction 1

EQ Indoor Environmental Quality – 13 Points

1. Enhanced Combustion Venting Measures 2
2. Enhanced Outdoor Air Ventilation 2
3. 3rd Party Performance Testing 2
   
4. Enhanced Local Exhaust 1
5. Better Air Filters (MERV 12) 1
6. Indoor Contaminant Control During Construction 1
7. Preoccupancy Flush 1
8. No Garage 3

AE Awareness and Education – 2 Points

1. Enhanced Training 1
2. Public Awareness 1

94 Total Points Targeted
136 Total Points Possible
83.5 Points Needed for Platinum (based on our home size)

Working through the LEED process on the 100k House project has made me think about the ways in which the government is and should be involved in sustainable progress. LEED is, of course, a voluntary certification program. There are no laws requiring its use (in residential building at least), and no government incentives for adhering to it. It is a great tool for organizing a building project and has growing marketing clout, but LEED doesn’t have the power of legislation behind it. Lacking that it grows slowly and is vulnerable to other watered down “green” certification programs that are easier on the builders and developers that choose to use them.

The solution could be to legally require LEED in some segment of new residential building projects, but is that the role of our government? Should legislation trump the natural workings of market forces or should we allow the demands of consumers to be the sole factor deciding the future of sustainability? There are those on both extremes of this argument, but I believe the solution, as usual, lies somewhere in between.

One of the key, but often forgotten, purposes of legislation is to educate. Even the smartest among us (and most of us aren’t the smartest among us) can’t possibly be educated in enough topics to understand the effect of . . . well . . . everything. The government, on the other hand, is in a position to collect the combined learning of a great many people and share the important information with its citizens.

Sometimes this dissemination of information can be done through pamphlets or a detailed white-papers but with over 20% of us functionally illiterate (beware of boring PDF) and a far greater percentage functionally disinterested, it is a long shot. Other times, television can be a useful tool to disseminate information, but then you’re competing with Two and a Half Men and sensationalist news stories. Try talking about mitigating the effects of energy loss through better insulation against thermal bridging when, one channel over, a man has kissed his girlfriend to deaf (that’s right I said deaf).

Legislation can be a solution to this problem. If something is important enough to be incorporated into law, more people will be inclined to find out why (or at least listen to their TV explain it to them). When the government outlawed lead in paint, many of us spit out our mouthful of paint chips, scratched our heads and said “What? Lead is bad for you?” Now, the unpleasant effects of lead are fairly common knowledge.  People often lack the information to choose actions that are in their best interest, and legislation is sometimes the most powerful means of delivering that information.

Of course, there is bad legislation. There are laws that teach us the wrong lessons. I won’t go to far into those since I try to avoid what some might call “politics”, but I’m sure we can all think of a few recent examples. There is also, I think, a balance between laws that are proscriptive and laws that are educational. Proscriptive laws tend to ignore the potential of the market and demand obedience without room for thought or debate. Educational laws leave space for innovation and evolution. This is more difficult to judge as it has to do with intent, but I will return to the LEED example to try to explain what I mean.

A proscriptive law might be, “All new homes built in the US must be LEED Certified.” This law ignores the market entirely and attempts to effect change simply through force. It ignores conditions which will damage its effectiveness such as a shortage of expertise and an inability among the majority to understand the necessity of such a law. This law’s intent is not educational. It does not lead by example. Rather it demands immediate, blind adherence which kills creativity and threatens market stability.

A better law might be, “all new homes built using federal funds or subsidies must be LEED Certified.” This law leads by example and, in doing so, educates. The market is still free to act, but the requirement signifies the importance of what LEED embodies. This law also recognizes that LEED may not be the best standard in the end and allows the market room to pursue other ideas. With a proscriptive law, other ideas are weakened or killed.

Now, I am aware that what I am saying is already happening. Many government agencies are requiring LEED certification for their buildings and there has been a good deal of legislation in the commercial market. However, I stuck with the example because I think there needs to be more of a push in the realm of home building. Weaker programs are being developed to allow “green” certification in less sustainable projects, and the consumer is in no position to judge their merits. Most are simply not educated. LEED is not perfect but it could be a great tool for moving us toward perfection.

I’m sorry for the length of this post. I tend to go on a bit, particularly when I don’t really know what I’m talking about. I am no expert on legislation, but I hope that by putting these thoughts down I might draw out someone with that expertise. So, come on out green lawyers and political pundits. Tell me how I’m on the right track or how I’m raving like a lunatic. Either way I want to hear your opinions on the best way to educate the public on the importance of building sustainably and the way in which legislation may or may not be involved in the curriculum.

Let’s get the comments rolling and remember . . . disgree with class.

Now that we are getting close to groundbreaking I guess it’s time to take a quick look at the LEED for Homes Checklist to make sure we are still on target. Originally the goal for the project was only Silver, but since meeting with MaGrann for our design charrette and preliminary rating, we realized that Platinum was as very achievable goal. Shocking on such a small budget, but true.

After pulling up the original spreadsheet that MaGrann filled out for us, I realized that we have made a few changes and upgrades that should allow us a few additional points. After completing a full review of the LEED Checklist, it now looks as if we have a ten point buffer to obtain the Platinum rating! This is still dependant on the home being classified as a two bedroom home which should not be a problem, but is not a certainty given our open floorplan and almost complete lack of doors (at one point I wanted a curtain on the bathroom to eliminate all doors).

Due to the home’s small size, it gets six whole points knocked off of the Platinum threshold, which takes the target score from 90 to 84. Currently, the 100K House’s point total is at 94 which gives us our ten point buffer. We could screw up any number of things and still get Platinum. That makes me feel better as I am imagining a few things will not go as planned.

For a review of the project’s LEED process early on, check out some of these previous posts:

• LEED Design Charrette Today
•  Results of the LEED Design Charrette
• LEED for Homes Basic Process and Fees
• LEED for Home Rating System

Ten point buffer! Double digits! How ’bout them apples? LEED only for the wealthy? LEED can only be done for a premium? Please! C’mon!

On Wednesday we received our HERS rating evaluation based on our final design from MaGrann Associates who is handling our Energy Star and LEED certifications. We have been working with MaGrann and Zero Energy Design to make improvements to our envelope design and mechanical systems since our initial HERS rating came back much higher than our target score of 50 or 50% more energy efficient than a standard code built home of the same size.

The target of 50 helps us achieve two major goals:

1. We will be eligible for the energy efficient builder tax credit from the Federal Gov’t for $2,000. This will pay for the solar thermal system along with the Federal solar incentives.
2. A HERS rating of 50 will give us the points we need in the Energy section of the LEED checklist to obtain our goal of LEED Platinum certification.

MaGrann took our updated mechanical design and actually used some more conservative figures in order to make sure we had some slack if we needed to make minor adjustments at the last minute due to budget. MaGrann also calculated the potential energy use and cost of the house based on our design and I was happy to see that their calculations matched those that Zero Energy Design came up with a few months ago. The total utility bill including both gas and electric is estimated to be around $1,300 a year or just over $100 a month. Since we will be occupying the home for its first years in use, we will be able to compare actual figures to these estimates.

These results are a big load off of my mind as I can finally shift my research focus from the mechicals to the other design and LEED details of the project that still need to be nailed down. Have a great weekend and stay tuned for more geeky research related posts in the coming weeks on ventilation, finishes and green landscaping.