Peabody Fine Architects

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Christmas update on the Fairfax Zero Energy House

We are getting near completion of the project, as painters are busy finishing walls and trim and we continue to await the arrival of the high pressure laminate paneling for the exterior. We are now told that that will be in the first week of January. All the areas on the exterior that are now black will be covered by a rain screen of 5″ wide horizontal panels in a simulated wood finish.

The rear sun protection canopy is now complete. The trim band at the exterior will be painted to match the recessed band in the stucco. The underside of the canopy will have the same HPL simulated wood strips that we will be using blow on the black area. That black area is also EIFS, but with a dark finish so that it will not be seen behind the simulated wood rainscreen.

Ditto the front entry canopy.

Above and below: interior trim going up at the stair opening, as seen from the front entry.

The upper stair hall. Railing yet to be installed. Clerestory windows above provide light to the interior of the house. One large unit will be operable by remote control to provide natural ventilation in spring and fall, taking advantage of the Venturi effect created by its height.

Phase two of the project is the garage. We now have the permit for that work and excavation will begin in January. It will be the foreground structure in the image below.

December 21, 2016
The Fairfax Zero Energy House: Mechanical system overview

The mechanical system for the Fairfax house differs from our earlier houses in several ways. We have zoned the house differently; we have taken a different approach to the heating and cooling equipment; and we have changed the ERV equipment.

This house is zoned from side to side rather than up and down. This decision had to do with the very different window configurations on the north and south sides as well as the room arrangement in the house.

The Rockville and Bethesda houses have a multi-zone heat pump with two ducted mini-split units: one for the top two floors and one for the bottom two floors. This house has three independent and very small (9000 btu) ducted mini split heat pumps. One unit handles the north half of the house; a second unit handles the south half of the house; and a third unit handles the basement space. We could have gotten away without the third basement unit, but there will be a computer room in the basement with multiple work stations, as well as large groups of people from time to time. The basement unit won’t run much, but when it does it will definitely be needed. This approach was a little more expensive than the multi-zone unit approach but it made sense in light of the fact that this will be a zero energy home. The efficiency of the independent 1:1 minisplits (23 SEER) is far superior to the multi-zone approach (16 SEER). The lower energy demand translates directly to fewer solar panels on the roof.

In the Rockville and Bethesda houses we used Zehnder energy recovery ventilator (ERV) units. In this house we are using the more economical CERV unit by BuildEquinox. A CERV (conditioned energy recovery ventilator) is basically an ERV with a small heat pump inside it. In addition to exchanging heat and humidity from the incoming and outgoing air streams, it conditions the incoming air. While a standard ERV may have 90% efficiency in the temperature exchange, the fresh air coming into the room will still be colder than the room air in the winter and hotter in the summer. With the CERV, the incoming air is at exactly the right room temperature. The other advantage the CERV offers is that it doesn’t run all the time the way an ERV does. BuildEquinox likes to call the CERV “an ERV with a brain.” Built-in software that can be accessed from an IPad monitors VOC’s, CO2 and CO, and turns on the fans when needed, saving further energy. Peter Schneider has had success with this equipment in his VerMod homes and we are following his lead here.

December 10, 2016
The STATE of PH in Multifamily

I was recently asked by a high-performance product sales rep whether I can forecast the near future for acceptance and adoption of the Passive House (PH) standard in our state and local jurisdictions for the affordable housing sector of development. This is a big question in our industry and I only wish I held the crystal ball. To put my response succinctly – I do not know, but I am hopeful. With this stated, one can first look back to see where we were, say 10 years ago when the energy codes were toothless, what we’ve worked through (deep economic recession), and witness at the national scale for PH in larger buildings.

Washington Square Town Homes project: insulated stem walls on one of the walk-up buildings

This past September, I had the pleasure to attend the annual PHIUS conference in Philadelphia. These conferences serve as very useful yearly status checks on how the PH movement is taking hold in North America. One of the breakout sessions featured a panel of representatives who are or have been directly involved with multifamily development, the implementation of housing finance policy or have spearheaded PH adoption in their respective local region. The panel featured Stan Salwocki of PHFA (Pennsylvania Housing Finance Agency), Mike Harsma of SDHDA (South Dakota Housing Development Authority), Chris Mahase of NYCHPD (New York City Housing Preservation & Development), and Linda Metropulos of Action Housing, Inc. of Pittsburgh. The panel offered a great volume of firsthand accounts and insight on the implementation of PH as well as the follow through of project teams working to bring them to market.

Pennsylvania

We would be remiss not to mention Tim McDonald (Onion Flats), Laura Nettleton (Thoughtful Balance) and Katrin Klingenberg (PHIUS) for their heavy-lifting in advocating for PHFA’s inclusion of scoring incentives in their 2015 LIHTC (Low Income Housing Tax Credit) Qualified Allocation Plan. As Stan Salwocki reported, in 2015, of 40 awarded projects, 7 of those targeted PH prioritization. And to follow that, for the 2016 round, of 27 awarded projects, 10 of those targeted PH. These ratios are astounding to us for the fact of how competitive the state-issued LIHTC program is, not to mention, how valued the additional 10 of 140 scoring points are to competing developers. All said, between these two LIHTC offerings, 850 new dwelling units designed to the Passive House standard will be available to low-income residents.

Peabody Architects is among one of the development teams in delivering one of the 2015 PHFA LIHTC projects. Through the Washington Square Town Homes (WSTH) project, PIRHL Developers and Contractors (Cleveland, OH) will deliver 54 affordable apartments to downtown Chambersburg, PA. The project is now under construction after long and deliberate design development and bidding phases. From our perspective, having designed and administered other Passive House projects of varying size and complexity, the project team has steadily become cognizant of the added responsibility to construct integrated and high-performing building. Getting to this stage even, is evidence that what once seemed to be a very high hurdle for production development, now really appears to be achievable.

WSTH: 12 townhouses go vertical (photo credits: Weber Architecture)

New York City

As Mr. Mahase reported, New York City has a tangible impetus for PH in their projects. We’ve all come to know that NYC has a unique model for leading in innovation and development. Currently, their policies are in the “feasibility and assessment” phase, much like PA. Sustainability by means of high performance buildings is a political issue for their mayor, framed by the 80 by 50 sustainability goal. The SustaiNYC program identifies Passive House by name as a tool to meet their long term energy goals. This is seen within NYCHPD’s recent affordable multifamily RFP. With many PH projects now in the pipeline and with demonstrated success (proven energy savings), city officials look forward to moving into the “incentives” phase where they plan to offset any premiums attributed to constructing better buildings.

Washington, DC

It is clear that DC government sees Net Zero Building development much as NYC does. Both DDOE’s Clean Energy DC report and the Sustainable DC Plan are evidence of the intention to lead by example.

Perhaps just as exciting, is that the District’s Department of Housing and Community Development (DHCD) has begun to incentivize net zero buildings and Passive House. Through both the PADD and LIHTC programs there are bonus points available to development teams using energy and performance-based standards on their scorecards.

excerpt from DHCD’s Green Building Overview

While 2032 seems like a long way off, let’s consider what this is saying. By this, it appears that the development and construction community should be warned to proactively prepare for significantly more stringent building codes coming down the pike. Considering the huge amount of underutilized, outdated, and unsafe buildings that exist in DC, this will be a large scale undertaking and we don’t think labeling it as a revolution is hyperbole at this point.

WUFI Passive energy modeling – beauty in the eye of the beholder

We look forward to continued updates on the progress of our projects and the STATE of PH in the world of multifamily.

December 2, 2016
The Fairfax City Zero Energy Home: Building Envelope Discussion

Our last post for this project was back in June, and we have come a long way. I want to focus in this post on our decisions about the building envelope.

The exterior wall framing of the house is 2×6 wood stud construction, filled with densepack cellulose insulation. Our original plan was to clad this frame with the ZipSystem sheathing we used on the modular Passsive House. That would then be covered with 5” of Roxul mineral wool batts and clad with a rainscreen of high pressure laminate panels. We liked the Fiberesin Stonewood panels because they were the most affordable. We proposed to anchor the rainscreen furring to the framing through the Roxul with special long galvanized screws – a system which has been used on the west coast, sometimes through as much as 10” of insulation. After adapting that to some degree so that our engineer would sign off, we got push back from the subcontractor who was going do the installation. In the end, we simply could not get installation costs down to a reasonable level.

We switched to the EIFS system we used on our Rockville Passive House, and will only be using the Stonewood for accent areas. Working again with AIrd, Inc. we asked them for the finest, crispest finish they could provide and they have not disappointed. They applied their “Limestone” finish with integral coloring over 5” of EPS foam. In the end we have a better product for less cost. One reason for that is we substituted ½” plywood wall sheathing for the ½” OSB ZipWall system. Instead of using tapes for our air sealing we now have the STO Stoguard liquid applied air water sealer over the entire wall, which is part of the EIFS system.

Here are some pictures. I’ll start with a sequence showing the various stages of clothing the building, then follow with some details…

Walls went up,

Scaffolding went up and walls were coated with Stoguard, the first component of the EIFS

EPS foam went on, the second component of the EIFS

The first coats of stucco went on

Final coats went on

The scaffolding came down

Window corner showing Stoguard covering Tescon Vanna air sealing tape. (The blue is temporary tape attaching the protective polyethelene over glass.)

Preparing the EPS panels for attachment to the wall. They comb the adhesive vertically to hold
the EPS off the wall, creating a drainage plane and capillary break behind it. Thicknesses of up
to 12″ of EPS can be applied this way.

The south canopy is put in place after Stoguard coating is applied over the plywood. Note the
high density foam spacers behind the steel which create a thermal break at the wall plane.

EPS boards after installation, before leveling

Leveling the EPS. It reminds be of the way wooden boatbuilders fair the hull with “longboards” –
boards just like this covered with sandpaper.

An EPS board after leveling and after the accent joint lines are cut in.

Rough stucco at a window sill

Finished product

EIFS work is now complete and carpenters are working inside applying trim and flooring. In a couple of weeks the another crew will apply the high pressure laminate rainscreen system at the indentation at the front door and at the projecting breakfast bay.

November 8, 2016
Our Team Wins Project for 8 Zero Energy Ready Homes in Fairmount Heights

The Prince George’s County Department of Housing and Community Development has just announced The Housing Initiatives Partnership (HIP) the winner in a competition to develop eight abandoned home sites. Seven of those sites are in the town of Fairmount Heights; one is in Capitol Heights. HIP, a non-profit affordable housing developer in Prince George’s County, was our partner in the development of the prototype modular Passive House just completed last year in Fairmount Heights. We plan to adapt that prototype to these sites, building upon what we have learned.

What makes the project particularly interesting is that six of the houses will be on contiguous lots, each with prime solar orientation. This presents an ideal situation for a case study hybrid direct current microgrid (HDCM). Much has been written about the potential for residential dc nanogrids and microgrids (including my own post last month). They are expected to transform the enegy grid from a centralized, vulnerable, top-down system to a distributed, transactive energy system within the next ten years, yet no residential HDCM’s have yet beeen built in the real world. As a HDCM the six homes will essentially become their own power plant, sharing site-generated solar energy among themselves and selling the surplus energy back to the grid. During power outages, they will continue to produce and store power. During peak energy demand periods when rates rise, they will go offline, using their own energy stored in batteries if they need more energy than they are producing on-site.

The key to creating an affordable HDCM is to reduce energy demand to the absolute minimum so that a minimal investment in photovoltaics and batteries is required. Passive House construction techniques and new generation high performance variable refrigerant flow (VRF) heat pumps reduce heating, cooling and hot water energy demand by 85% below standard homes. But they do nothing to reduce the electrical demand of lights, appliances, TV’s, computers, etc. This is where switching the house over from alternating current to direct current comes into play, with the potential to electrical energy demand a further 50% by some estimates. My previous post goes into why this is, so I won’t repeat myself here.

With the help of Dave Geary of Power Analytics, Terry Hill, who sits on both the PHIUS and EMerge Alliance boards, and Stephen Pantano, of CLASP, we will now begin the process of assembling products, expertise and funding for the case study microgrid design and implementation.

Our team for the construction effort is:

Housing Initiatives Partnership, Developer
OMF, Builder
Pando Alliance, Third Party Testing and Energy Certification
Subcontractors have not been determined at this point.

Construction is anticipated to begin on the first three homes in the summer of 2017.

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November 3, 2016
Direct Current Microgrids: The Next Big Thing
By far the most exciting development in building construction today has little to do with building construction; it has everything to do with how we power our buildings. Passive House techniques have perfected how we assemble the building envelope and how we heat, ventilate and cool buildings. Through these techniques we have been able to reduce heating and cooling demand by 90% from where we were at the turn of the millennium. But these techniques only deal with energy demand; they do nothing to affect energy supply. To get to affordable zero energy and energy positive homes, the building industry now has to tackle the supply side.

Alternating current, advocated one hundred years ago by Nicola Tesla and George Westinghouse and set as the standard for the transmission of electrical power, stands in the way. We are moving to a direct current (dc) world. Consider this:

Photovoltaic panels generate energy in the form of direct current. Battery systems store energy in the form of direct current. Your refrigerator and the motors in all the new high performance mechanical systems are driven by direct current. LED lighting uses direct current. Your computer, your phone, your TV and other entertainment devices and your laptop all use direct current. Yet every one of these items requires a rectifier/power supply (the little box you plug into the wall when you charge your phone, for example) to convert alternating current to direct current. Every time that conversion happens, energy is lost in the form of heat. When we are talking about on-site generation and storage of energy, those cumulative losses can become significant – as much as 50% according to Dr. Rajendra Singh at Clemson University.

Onsite energy storage in batteries is growing by 40% a year according to Navigant Research. Yet think of the path of electrons from your rooftop solar panels: The first thing they do when they leave the roof is get converted to ac current so they can move across your house to the battery storage system. There, they immediately get converted right back to dc to be stored in the battery. Then they leave for, let’s say, your refrigerator and they get converted again to ac to get to the fridge. Once there, they get converted yet again so that they can drive the variable speed direct current motors of the refrigerator compressor. That is four conversions! Each with a significant loss of electrons in the form of heat.

Now what if the wiring system in the house were a 380 volt direct current system? It is easily doable since direct current can be transmitted in standard household wiring. Then there may be no need for any other conversions for 380vdc power devices or the only conversions necessary would be stepping voltage up or down as/if required by the motor or appliance – far less of an energy loss. Today roughly 1/3 of all electrical items in the home are native dc. With very small changes, 2/3rds or more could be native dc, and as mentioned before, solar and battery, as well as wind systems, are all native dc.

The only thing that stands in the way of changing the “language” of our household energy from dc to ac is inertia. But things are changing quickly. Here’s how:
- Just last week the National Electrical Code announced a chapter covering dc microgrids in its 2017 code book.
- In September Mitsubishi announced that they are now going to make a dc powered mini-split heat pump (like those we already use in our passive houses). In addition they have announced they will be producing a dc powered energy recovery ventilator.
- The EMerge Alliance is in the process of creating international standards for dc voltage within multiple use cases.
- CLASP is pioneering the development of dc powered appliances, both for the western markets as well as the third world where energy efficiency can make a difference between being able to purchase basic necessities or not.
- Already there is a broad range of dc lighting products available and more are coming onto the market each year.
So where is this all going?

With the ability to create a nanogrid – solar power with battery storage and energy management software—homes can now be “islandable”, that is, self sufficient during power outages; or be designed to be totally off-grid. They can also sell energy back to the grid during peak load hours. These attributes are priorities for government and utilities, both of which are increasingly concerned with the resilience of the grid as well as leveling out peak loads to eliminate the need for additional power plants.

Linked together in neighborhood microgrids, these individual nanogrids become virtual power plants, where energy is made and traded. Such virtual power plants are now a fact of life in Texas and California. With the growth of battery storage capacity (tenfold from 2014-2015 in the US), a new transactive energy economy will be born. Navigant Research projects that $2.1 billion will be spent annually on implementation of virtual power plants by 2025. See their chart below of the current growth of battery storage.

How can we as architects and engineers ignore this trend and not change how we wire our new homes? In our practice we are now making all of our new homes as dc-ready as possible so that in ten years when the shift has happened, conversion will be simple. Within that time period standardization will have occurred among product manufacturers and among UL, NEC and other regulatory groups. Because of the work of The EMerge Alliance and other national and international standards organizations, 380v dc will be the new 120v ac, and the nice thing about that is that today’s household wiring can carry that voltage. All we need to do at this point is to provide the circuits necessary for battery storage and solar production, as well as dedicated dc and ac outlets.

Right now we are working to develop a case study hybrid dc microgrid in a new project in Maryland. The proposal involves six contiguous sites and six identical modular zero-energy houses to create the first sustainable dc powered community. Each house would have its own nanogrid. The six houses would also be interconnected through a dc microgrid. With the help of Terry Hill, who sits on both the PHIUS and EMerge boards, we are working now to assemble products, expertise and funding for the case study microgrid design and implementation. While many technical papers have been written on the advantages of direct current, and small academic demonstration projects have been set up, no true real-world hybrid dc microgrids have yet been built to put theory into practice. This project would do that at a residential scale.

To learn more about the potential and rationale for direct current, CLASP has put out an excellent white paper on the subject. There is also an excellent article and references on virtual power plants in Microgrid Knowledge.
October 17, 2016
Takeways from the 2016 North American Passive House Conference

We just got back from the PHIUS national conference in Philadelphia. It was quite well attended, with a broad array of topics covered. These conferences are no longer focused simply upon how to do build one, but have become much more specialized and look at all the various aspects of what goes into a Passive House. They are also looking at other building types that are now employing Passive House design principles – multifamily housing, office buildings, schools, and even high rises. We have come a long way!

Takeaway 1: The biggest takeaway, I have to say, is Izumi’s: she went through the day-long training for the new PHIUS WUFI+ energy modeling software. Quite rigorous. She has immediately put it to work on a current project in the office. Matt learned this software when he did his PHIUS training. So that leaves me as only one who hasn’t made the shift to the new WUFI+.

Takeaway 2: Spray foams aren’t as bad as we thought. Several years ago Alec Wilson of BuildingGreen published an article positing that the global warming potential of the gases in the blowing agents far out outweighs the savings in CO2 emissions that these products give you. Bailes examined the assumptions of Wilson’s calculations and made a strong case that the issue is not quite so black and white. His argument is that the EPS and XPS foams’ savings in emissions actually exceed the environmental cost of the gases in the blowing agents when you apply it in thicknesses of roughly R-20 or less. This is based upon the declining increase in R-value with each extra inch you add. He did not address other issues around the foams: the lethal gases produced if they catch fire, and the fact that they are fossil fuel based. The takeaway for me: yes, it is ok to use these products in small amounts where there is not another alternative insulation system that would work (such as some retrofit situations). The exception is XPS insulation (extruded polystyrene–eg: Styrofoam) for which one can always substitute the more benign EPS (expanded polystyrene) insulation. To learn more, read Allison Bailes’ article, which also references the Alex Wilson study.

Takeaway 3: … and cellulose insulation isn’t as perfect as we thought. Prudence Ferreira gave a very detailed review of the performance of different insulation types in various climates with regard to mold and wood rot. Her studies taught her that cellulose insulation—either loose or densepacked—tends to hold moisture longer than other insulations. This can become a problem at the outside edge of your insulation cavity where moisture can accumulate and remain if the surface bounding the outside face of the insulation (usually the building sheathing) gets cold enough. What it tells me for our climate is that we always need to have rigid insulation on the outside face of our sheathing to keep it from getting too cold and causing these problems. Luckily, that has been our practice to date. A wall that would not work well in our climate, for example, would be a double stud wall with nothing outside it. Even though the wall might be 10” thick and achieve tremendous R-values, it could develop moisture problems at the interior face of the sheathing.

Takeaway 4:Hybrid AC-DC microgrids are coming. Terry Hill, who sits on the board of both PHIUS and the non-profit EMerge Alliance, moderated a very interesting panel including Brian Patterson, the founder of the the EMerge Alliance and Tim Martinsson, CEO of Power Analytics a leading firm in microgrid design. We learned of the latest developments in microgrid technology and products and their application to individual buildings. We are working with both of these groups in trying to develop a case study project for a home powered by a hybrid microgrid. I’ll be blogging more on this later.

September 30, 2016
Matt and David to Lead Class at 2016 North American Passive House Conference

Matt and David have been asked to give a half day seminar on the special issues related to construction of Passive Houses in our climate zone. We will be talking about building envelope strategies we have used and the evolution of our thinking regarding heating and cooling and ventilation in this climate.

September 16, 2016
Peabody Architects guides affordable multifamily development to PHIUS+ 2015 Passive Building Standard Precertification

A WUFI Passive energy simulation of the Washington Square Town Homes project. Such models strip away the articulation of a building’s skin and focus on the basic thermal and airtight boundary which directly affect its energy balance.

The design, consultation and pre-development team has been hard at work for over eight months to deliver one of the Passive House (PH) projects awarded in the 2015 round of Low Income Housing Tax Credits (LIHTC) through the Pennsylvania Housing Finance Agency (PHFA). Of the 40 awarded applications for the 2015 round, 7 of those development projects have targeted Passive House energy performance standards.

The Washington Square Town Homes project, for which we serve as Certified Passive House Consultants (CPHC®), comprise (4) buildings, including (12) townhouse units and (42) walk-up apartments. The project is to be located within the Borough of Chambersburg, PA where the need for quality, sustainable affordable housing is great – just as it is throughout the DC metro region. PIRHL Developers and Contractors of Cleveland, Ohio are the Developers and Builders on the project.

One of our primary tasks on this project is to “demystify” what it takes to deliver a Passive House. Simplified sketch mark-ups serve as one of many tools to bring teams to common ground.

With the knowledge that this is an ambitious undertaking, we are proud to have crossed two very important thresholds on the delivery of the project.

Just recently, we have obtained precertification for PHIUS+ 2015 Passive Building Standard of all 54 dwelling units. This project currently stands as one of less than a handful of multifamily projects in the U.S. to achieve this. This status is obtained as a result of our WUFI Passive energy simulation meeting the climate-specific energy metrics and having coordinated building envelope design, detailing, specifications and HVAC systems. PHIUS provides a comprehensive quality assurance review of DD-level drawings and back-up documentation to confirm accurate WUFI modeling and risk- free building science.

http://www.phius.org/phius-2015-new-passive-building-standard-summary

To add to this, the project has now been bid competitively by subcontractors. In the process, we helped lead a day-long prebid meeting where the project (and largely, the concept of PH) was introduced to interested bidders.

With the assistance of 475 High Performance Building Supply in the mock-up construction of a 4’x4’ sample wall panel, we were able to fully describe the building envelope system to contractors.

Delivering a Passive House building envelope does not require new technology. It only requires thoughtful design, committed coordination, informed building science, and well-executed construction. Studies of solar exposure and paths along with thermal bridge modeling and analysis are all part of CPHC® responsibilities.

We eagerly await the results of the bidding process to see where the numbers land within the next few weeks. Construction is due to begin this summer.

Even after nearly 10 years since PH has come to the U.S., it is true that work such as this is still to be categorized as “pioneering”. We know, firsthand that large scale Passive House development requires a committed developer, design and construction team. Having learned from past projects and as well as case studies around the country, we also know how reachable and repeatable these projects can be. With this in mind, it is our belief that Passive House multifamily must be recognized as the rule rather than the exception by our state and local governments to create high quality, sustaining, and ultra-healthy housing developments.

As evidence to what we see the uptake to be shortly, PHIUS has just introduced an online resource for multifamily developers to better understand the process, criteria and benefits to Passive Building certification.

http://multifamily.phius.org/

June 15, 2016
Second floor walls going up on the Net Zero home in Fairfax.

There are big changes to see since my last report. The rains finally ended, and O’Neill Development wasted no time in getting underway on the framing. This is an exciting time for both the owner and the architect, finally seeing the form of the building take place so quickly after months and months of planning. Here are some pictures from the last few weeks, the most recent being this morning…

The two steel beams carrying the first floor. The one on the left is a 28′ span, which will allow the rec room to be clear of posts. That was heavy — a W16x67, almost a ton!

First floor decking and framing waiting for the rains to let up.

Basement walls completely buttoned up with insulation and drain board.

The haunches that will carry the front entry slab.

The site this morning. They had just tilted up the two second floor walls before I arrived. This is the front entry facade.

Those walls are all braced frames, meaning all the nailing and blocking are completely installed before it goes up. Took six men two tries to get this one in place.

The recess at the front entry door. We are using standard 2×6 framing on this house. We will insulate those walls with cellulose and then add the extra insulation we need to the exterior using an EIFS system. More on that later.

Post and beam at the front entry.

Looking from living area toward kitchen area. First floor ceilings are 9′.

Preparing to tilt up one of the second walls.

Here is a film clip of the general scene this morning..

IMG_4054

and here is one of them tilting up the wall in the picture above…

IMG_4055

May 28, 2016