good news

mtl roof noyesyes, that is a roof!  not only does it look great, but it will keep the weather out of the house so we can continue with interior finish-out – disaster narrowly averted.  on friday, the city conducted their rough-in inspections – we passed all with flying colors.  now, we can leave rough-in/subcontractor hell behind and move onto the fun stuff, like interior finishes!  oh yeah, solar PV panels will be installed this week. so, by friday we will be making some electricity! train kept a-rollin’….

 

building shell blower door test

as previously discussed, a BIG performance component of this house is tightness.  most (all?) design and constructability decisions have been founded upon the principals of building shell tightness.  these include walls/roof (SIPs), windows, doors, foundation details, etc.  the basic idea is to build the house as tight as possible to keep that precious (costly!) heated air INSIDE.  of course, in so doing,  we must also be cognizant of occupant health.  if it’s too tight, then we can induce indoor air quality problems (moisture, pollutants, etc.).  the catch phrase is “build it tight, ventilate it right”.  what follows is some info on the “build it tight” part.  more to come on the “ventilate it right” part….

in addition to design and attention to detail during construction, we must test ourselves.  that’s where the blower door comes into play.  basically, a blower door is a door that blows air out of the house thereby creating a negative pressure inside (it can also blow air into the house, thus creating a positive pressure, used mostly as a diagnostic method).  WARNING: what follows will go some distance down the “building science” road, but NOT all the way down that road – three reasons.  1) i’m an architect, not a scientist!  2) the purpose of this blog is to present a wholistic presentation of the design and construction of 363HOUSE.  3) due to #’s 1 & 2, i’m trying to keep the information mostly accessible to the non-greengeeks amongst us!

blower door.  basically, a fabric door with a big fan.  the little gray box near upper left corner is the manometer.

blower door – basically, a fabric door with a big fan. the little black box with keypad near upper left corner is the manometer.

the blower door is equipped with a computerized manometer to measure air pressure.  the industry standard is 50 Paschals (50Pa) – a Paschal is a unit of measure like inches of water column.  it’s been described to me as the equivalent of a 20mph wind blowing on all exterior surfaces (roof, walls, floor/foundation) of the building simultaneously.  the manometer reading is rendered in Cubic Feet per Minute (CFM).   the lower the number, the better.  that CFM number is factored to obtain so many Air Changes per Hour (ACH).  again, lower is better.  so, basically, the resultant calculation tells us how many complete air changes will occur in 60 minutes at 50Pa.  so, that’s interesting, huh?  if you’re still reading this, then you might be wondering, “well, how many (or, few) is good?”.  here’s a VERY brief primer….a reasonably, well-constructed home of “conventional/non-airtight” construction might be 15ACH@50 or more;  under the 2009 International Residential Code, ≤7ACH@50 is required; an EnergyStar 3 house, ≤4@ACH is required; PassivHaus, the uber-standard for TIGHT construction, ≤0.6ACH@50 is required!

our energy model (see “energy” posted WAY back on 13 june 2012!) is based upon 1.5ACH@50Pa.  we chose this target based upon previous experience and knowing that this project has many goals and a budget.  so, the thinking was let’s not over-reach on every goal.  nonetheless, we have been OBSESSIVELY attentive to tightness with every intention of smashing our energy model goal!

so, how’d we do????

on friday, the manometer told us we did pretty good - 355CFM.  this translates into 0.95ACH@50.

on friday, the manometer told us we did pretty good – 355CFM. this translates into 0.95ACH@50.

frankly, we did NOT smash our goal.  yes, we did better than 1.5 by a little more than a third.  and, this is only the building shell blower door test (we can work toward improvement before the final blower door test at completion).  so, i’m satisfied with our work, but not ecstatic – no chest-pounding!  of course, the shell blower door should be considered a diagnostic tool – a learning opportunity.  yeah, so, what did we learn????

well, our uber-tight entry doors aren’t so uber!  the good thing about the uber doors is the hinges are nearly infinitely adjustable and we think we can tighten up the door seals through hinge adjustments.  we also found a few small breaches in the SIPs shell incurred by some electrical wiring (MORE spray foam!).  and, we have a few very minor leaks at window installation clips. the uber windows are indeed uber – no air leaks there!

BTW, leaks are discovered through the use of a smoke pencil. it’s just what it’s called, a “pencil” that emits smoke.  if the smoke leaks out of the building, then that means air is going out, too!  pretty cool, VERY effective, LOW-tech device!

diane milliken of horizon maine (project green rater) conducting the blower door test. NICE BOOTS! :-)

diane milliken of horizon maine (project green rater) conducting the blower door test. LOVE the boots!

one final thought.  i’ve always found the best way to think of this whole air leakage thing is in terms of “how big of a hole does this ACH@50 number equal?”.  think of it like this….if we added up the area of ALL the holes in the building shell (shell area = 5667 square feet), then the total would equal a 6″ diameter hole.

we plan to re-test in the next week, or so, after the above listed remedies have been employed.  i will report any improvements worth noting.

now, if i can just GET THE ROOFER TO SHOW UP!!!!

ps: here are the calcs, for those number freaks amongst us….

363HOUSE blower door shell

smarthome

jessica and todd have decided to install a “smart home” system.  basically, this will allow for control of audio, some video, heating, window shades, security system and lighting via software controlled by computer, iPhone, etc.  the in-house controller will be an iPad mini. its a pretty cool, whiz bang feature that has a deeply practical application for jessica, given her limited mobility.

so, when the sun glare/heat is too much or night-time privacy is needed, pull out the iPhone and lower the shades; when someone is at the front door, pull out the iPhone and see who’s there!; wanna control what rooms are receiving the piped music, pull out the iPhone; driving home and want some outside lights on for your arrival, pull out….you get it.

should be cool.  now, we just gotta get all the wires run before sheetrock starts!

update

well, rough-in continues.  the project is in one of those phases where progress seems to creep along.  and, the holiday season has put a bit of a damper on things (and i’m not just talking about the rain and snow!).  we remain hopeful that our roofer will make an appearance very soon. otherwise, once rough-in is completed next week, the project will come to a standstill.  ah, the joys of building! 😉

photo gallery of construction highlights:

rough-in

we are well into the roughing in phase.  plumber, electrician, fire sprinkler, solar and heating contractors have all been on-site.  the “smart home” sub will be on-site in january to do his work for control of lighting, audio, video and window shades.  oh yeah, gotta rough-in the HRV (Heat Recovery Ventilation) system, too.

given the compact nature of the design, no basement and essentially no attic, routing the multitude of pipes and wires is akin to building a submarine!  overall, its going well with minimal back-tracking.  nonetheless, it is a time-consuming process and has required a lot of time on-site by yours truly – all in hopes of starting sheetrock installation mid-january.  oh yeah, we STILL need the metal roof installed before that starts!  YIKES!!!!

unfortunately, no exciting visuals/photos of wires and pipes.  just this photo of the first floor electrical plan with my field notes compiled during a 90 minute walk-thru with craig the electrician (on-site nickname = “sparky”).  the result is the fourth iteration of the electrical plan. the march of two steps forward, one step back presses on!

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here’s a photo update of siding installation with west wall almost complete.  it DOES look nice, huh?

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update

Gallery

This gallery contains 11 photos.

recent construction progress seems meteoric compared to recent past. exterior siding and trim underway. LOTS of prep work (rain screen, flashing, etc., etc.) but worth the effort.  the siding installation itself will go fairly quickly (at least the “wood” siding, … Continue reading

rainscreen

a rain screen is an airspace behind the exterior siding.  it allows any water the might find its way behind the siding to drain.  thus, the building structure is better protected against water infiltration and the siding is more durable.  nothing new here – “rain screens” can be found in buildings that are hundreds of years old (it’s a major reason these buildings have lasted so long).  however, in our miserly quest to build cheaply (so the wall street /thieves bankers can pocket the dollars!), we’ve lost our way a bit.  the introduction of a rain screen into a wall assembly is relatively simple – but, it does add some costs.  historically, those costs have not been supported in the post-war building boom.  to satisfy the money guys, we only need to build houses that last 25-30 years (typical mortgage period).  so, that’s what we have been doing.  its time we change that.

this “in-process” photo shows the major components MINUS flashing and a few “odds & ends”.
1) “TYPAR” = house wrap/drainage plane.
2) vertical wood strips = 1×3 strapping to create 3/4″ thick air space.
3) black horizontal bands top & bottom wall and window = venting with insect screen.

the rain screen employed at 363HOUSE is VERY simple.  basically, it consists of three components:  1) house wrap as the drainage plane.  this protects the exterior surface of the structural wall (SIPs) from water.  house wrap also allows any trapped moisture behind to escape via vapor diffusion.  2) air space – we are using 1×3 strapping to create a 3/4″ air space between backside of clapboard siding and face of structural sheathing (SIPs).  the air space is of sufficient depth to allow water to drain and provide air flow to promote drying and pressure equalization.  3) flash and vent – the only “tricky” detail with a rain screen is paying close attention to flashing details.  basically, the flashing must bridge the air space – so, it spans from the house wrap outbound to the exterior surface of siding.  this is necessary for any water that might be draining down the drainage plane (house wrap) to find its way out above wall penetrations (doors, windows, lights, vents, etc.).  venting is important to allow any water to drain and air to flow.  so, we are using 3/4″ thick corrugated plastic vents with insect screen at the bottom and the top of the 1×3 strapping.

so, when all is detailed AND installed properly, the rain screen will protect our structure and siding from the potential damages of water/moisture.  this will result in long-term durability and lower maintenance.  all of this for a few thousand dollars, labor and material.

siding and trim installation starts this coming week!

lemonade

an ongoing construction issue has been the quality of the concrete slab finish.  the intent was for the concrete slab – stained and sealed – to be the finished floor.  our reasoning included aesthetics, durability, ease of maintenance, unfettered thermal mass (radiant slab and passive solar) and a responsive surface for jessica and her wheelchair.  in spite of overwhelming assurances from the concrete sub that the slab job would be “primo”, it is a mess!  we have ripples, voids, control joints in the wrong place, slab recess at the wheelchair lift too shallow, slab recess at the bathroom/shower (for tile) overlooked  – basically, its a FRIG.  we could have forced the issue with the sub and had the slab removed/re-poured.  but, due to schedule AND the radiant tubing throughout the slab, we opted to punt and re-group.

after months of debate, research and haggling, we’ve decided to salvage the slab via a ground and polished slab.  as a result, the finished floor will now have a crisp finish and better fulfill our above-mentioned goals.  the aesthetic will be consistent with the clean interior detailing of the house and the planned-for concrete countertops.  jessica and i are excited with the prospect of making lemonade out of our lemon-slab!  of course, it will cost more, but we are confident in its value.

here’s a photo of the sample slab at the subcontractor’ shop (NOT same guy that poured the original slab!).

the colored squares are acetone stain samples – we are not staining, just going with the natural concrete color/finish known as “salt and pepper” – not a great photo, but you can get the idea.

jon meade of meade designs in portland will be doing the grinding and polishing work.  here’s the basic scope of work: “Grind, hone, densify, polish and seal concrete slab. Planetary polish will begin at low grit of approximately 70grit, and proceed through 1800 grit.  A lithium densifier will be applied at 400 grit.  Work will proceed with HEPA system vacuums wherever possible.  Remedial grouting to porous areas will be used to those areas that require it.” 

the work should start as soon as we get permanent power connected – scheduled to happen before thanksgiving – we hope!  that’s another story….

window installation details

i know, the title of this post will attract lots of new followers!  in spite of this seemingly mundane topic, it is of vital importance to the performance of the building envelope.  windows are great.  they provide natural light and air.  windows provide a connection to the outside and are critical to human comfort and enjoyment.  windows can also be bad.  inadequately constructed windows can admit unwanted cold air and allow the loss of costly conditioned interior air.  a window can also leak water which can lead to unsightly water stains or decay/rot.  so, we must be careful when designing, detailing and installing windows.  the following documents the chosen window installation at 363:

typical window rough-in

this view shows the basic window rough-in.  the components include the window, Vycor tape (the black stuff at the perimeter of the opening), sub-sill (the black plastic thing at the bottom of the window), and the strip of house wrap (the mostly white paper thing at the bottom of the opening).  the components are layered top to bottom to provide positive drainage.  eventually, the entire wall surface will receive house wrap which will be the drainage plane – it will shed any bulk water that finds its way behind the siding.  then, 1×3 wood strapping will be applied over the house wrap to provide a rain screen behind the clapboard siding.  all of these layers provide durability by shedding unwanted water.  a future post will detail the rain screen components.

bottom corner detail

close-up showing the layering of the various components listed above. the black “GRACE” tape is the Vycor.  its doing two things in this application – one, providing primary weather (water) seal and, two, providing air barrier.  the piece on the “outside” corner (not next to window) is primarily an air barrier.  the SIPs opening has a 2×12 “buck”.  i’m concerned that this field marriage of dimensional lumber to SIPs cut-out will not be a perfect union (even with the two beads of sealant applied under the 2×12).  so, this “extra” piece of Vycor tape is cheap insurance against air leakage.  also note the black plastic sub-sill. it has sloped horizontal sections to provide positive drainage should any water find its way there.  this product is SillGuard, formerly manufactured by Marvin Windows and Doors.  “formerly” because i just learned that Marvin no longer is making this product.  we were able to buy out some remaining stock from EBS in camden. too bad as i have found this product to be a good sub-sill solution.  i guess the next project i’ll have to resort to site-built sub-sill.

interior bottom corner

now, we jump to the inside.  here you can see the 2×12 buck inset into the SIPs cut-out.  the metal clip is screwed to the side of the window and into the 2×12.  three clips per side and two at the top provide a secure window installation.  the gap between the side of the wood window frame and the 2×12 will be filled with spray foam insulation for thermal and air barrier.  the gray caulk at the bottom of the wood window frame reinforces the bed of caulk under the window frame – again, thermal and air barrier.

just in case you haven’t figured it out yet, ITS ALL ABOUT THERMAL AND AIR BARRIERS!  oh yeah, and water (bulk and vapor), too.  remember, we must negate those bad things listed in the first paragraph so the occupants can experience unfettered comfort and enjoyment of their beautiful windows!

progress continues….

in spite of the paucity of recent posts, construction has been progressing at a steady pace. the garage has been framed, roofing has been “roughed-in” (not totally watertight, but nearly so!), utility connections in the street completed (BIG deal!), and LOTS of miscellaneous framing, etc.  we are about a week behind schedule for our current phase.  not bad considering the wet weather we’ve had in october.  sunny, bright skies this week should help us on our quest to have exterior work 90% complete by thanksgiving – that is if HUNTING SEASON doesn’t slow us down too much!

three windows in this palette will be stacked into one 8′ w. x 9′ h. window in the living room.

at LONG last, the windows and doors (see previous posts entitled Drewexim Uno and Duo) were delivered to the jobsite today!  installation starts tomorrow with completion scheduled for next week.  the crew was impressed with the rugged (AND heavy) windows.  they are beautiful!  i think the client will be happy.