Exterior Doors…

July 11, 2011 by Jeff Erkelens

Tom has been busy this last day or so both manhandling and finessing our extra deep exterior doors into place. While we went with the Serious 525 fiberglass series for the windows, we just couldn’t justify the extra cost for the Serious doors. Plus, all Serious is doing is buying prehung doors by Thermatru and slipping their own glass into them, so it’s still a conventional frame.

Instead, we opted to buy Thermatru Smooth-Star fiberglass doors with just double pane low-e glass in them. To meet the Passive House Standards with the higher U-value door glass, our modeling called for increasing our exterior wall insulation from ten to eleven inches. Just that extra inch of insulation is still a few thousand dollars cheaper than the cost of the triple-pane Serious glass in a standard Thermatru door.

A few wrinkles: We were able to get Thermatru to make a 12″ thick jamb, such that our doors hinge on the interior side of our double stud and are able to swing freely. However, the deepest sill we could get was only 8″ deep. So, if you look at the photos, you can see the jambs of the doors stick past the actual sill by a couple inches.

To solve this flashing issue, we had Martin roofing solder up some copper door pans for our doors to sit in. It is probably overkill, but we also ran rubber and caulk below our copper door pan as well. Also, before seating the door in the pan, we adhered a thick self stick rubber membrane to the bottom of the aluminum sill such that it wouldn’t be in contact with the copper, which could potentially react and corrode the aluminum.

As far as aesthetics, Joey went with a 3/4 lite for our two front doors to try and have a little bit of a unique look.

Project: 6th Street SW · Tags: , , , · 1 Comment

One side done

July 6, 2011 by Jeff Erkelens

We’ve finished one whole side of the house, including the metal roof. It’s always a good feeling to tear down the scaffolding and reveal our handy work. Although with the corten weathering steel, we have to play the waiting game for the house to turn to that beautiful rust color and for our blue window trim to really pop.

A few details: While our material choices are pretty bold, we wanted our trim details to give a nod to tradition. For the window trim, we did a simple picture frame, but made sure to have a stool and apron on the bottom of the window. Before putting up the exposed trim, we used blocks of 1″ thick trex deckboard around the window that we butted the 7/8″ corrugated siding to. For the trex board that was below the window, we made sure to cut a bunch of kerfs on the side mounted to the house such that the drainage plane wasn’t impeded.  We used a brown trex board that is barely noticeable right now as the siding is still silvery, but once the siding ages, you shouldn’t be able to make it out at all.

The actual window trim is pressure treated yellow pine that is treated with borate that we got from Nature Neutral.  Our primary reason for choosing the borate treated instead of the normal pressure treated was not any environmental reason, but aesthetic.  Normal pressure treated that is treated with heavy metals always has a dark greenish tint where as the borate maintains it’s natural yellowish, clear tone.  Joey really wanted stained wood trim where you could still make out the wood grain.  I was really hesitant because of maintenance issues, but the pressure treated solution along with a Sherwin Williams semi transparent deck stain has got me feeling pretty good.  Throw that in with the trex blocks, the corten siding and the galvalume metal roof and we’ve got a shell that will be around for awhile.

One other play on a historic trim element:  At the top of the house underneath the roofline, we ran a frieze board of 1 x 8 miratec trim.  On top of that we  nailed up a 1 x 4 miratec and a 1 x 2 miratec to give the feel of a cornice wrapping the house.  We firred this off the house with the same trex deck boards such that the corten could slip behind it and our ugly cuts could be covered up.

The only last finishing touch is to build some window boxes, but that’s definitely way down the list of things to get done.

Project: 6th Street SW · Tags: , · Leave a comment

Serious Windows

June 24, 2011 by Jeff Erkelens

We have received our triple pane windows from Serious and have been busy working our way around the house. Today was spent installing the ten 5′ x 5′ double casements on the south side. More details next week. Feels great to be almost sealed up.

Project: 6th Street SW · Tags: , · Leave a comment

Serious Windows

May 23, 2011 by Jeff Erkelens

So, again, for this next house, we are going for Passive House Certification, which is still fairly new to the States, but has been around Germany for quite awhile.  A quick refresher: Rather than just being a points based system like LEED or Earthcraft, Passive House sets rigid standards that must be met both by computer modeling of the building and verification and testing in the field. Rather than relying on fancy and expensive systems like geothermal heating or solar hot water, the focus is on super insulation, airtightness and controlled fresh air.  One of the ultimate goals of Passive House is to have a home that uses 10% of the heating and cooling load of a normal house.

One of the biggest factors in achieving this is the windows.  We ended up going with the 525 series by Serious Windows for a number of reasons.  First, and most important, we are able to meet the Passive House standards with these windows.  It’s a combination of the window being triple pane and the thoughtful construction of the fiberglass frame.  When you look at the specifications of most new windows, they show the U-value of the window (which is the inverse of the R-value and refers to the thermal quality of the window).  However, this U-value is sometimes just the glass, and doesn’t take into account the whole window, including the frame.  When you get windows with really high performing glass, the frame of the window becomes the weak point in the window. The Serious 525 series has a whole window U-value of .22 (4.5 R-value) for the casements with high solar heat gain coefficients that we are using.

Serious has even higher performing lines of triple pane windows, but we are working with a modest budget.  Ultimately, it came down to price as other European and Canadian brands were just not affordable to us.  Even with Serious, we are paying about 65% more than what we have been spending on the Pella Proline series, which we have been really happy with in all our other houses. Honestly, if this was one of our spec houses, I don’t think I could afford to pull the trigger on these windows at this point because of the price as I unfortunately don’t think the market values all these energy savings though I’m hoping that will change.

The price of these windows was really the biggest moment of pause for us on whether to continue with Passiv House.  We calculate the payback as taking at least 20 to 25 years versus going with the Pella Proline, which is a long time.  But, there a few other advantages and cost savings because of these windows.  One benefit is the potential for condensation on the insides of the windows from relative humidity should be cut dramatically down. Another is the increased comfort level of hanging out close to the window and not feeling that temperature difference that you might feel with a double pane in the middle of winter. Coupled with the tightness of the house, the super insulation, and the ERV system, we are able to drastically reduce our heating and cooling load and go with a much more inexpensive hvac system.

Another cool aspect of the Passive House standard is that through modeling you actually spec different glass for different windows based on location.  Initially, this sounded really forward thinking and intuitively made sense as you would want a higher solar heat gain window on the south side, but not the west, to actually have the sun warm the house in the winter, but not overheat it in the summer.

Interestingly, the orientation and specs of our house dictated that we need high solar heat gain windows on all of our windows (SHGC=.40), which turned out to be a blessing.  For, you get much better visible transmittance with the high solar heat gain windows.  The 7, 9 and 11 series Serious windows can have either a blue or greenish tint to the glass and is noticeably darker.  This really catches your eye when you have two different types of glass in the same room, which we would have had because of the open floor plan.

Overall, I think we have always tried to strike that balance on our houses of having strong passsive solar orientation while still taking into account privacy, views and aesthetics. For us, it’s usually a bit of compromise when building in town on gridded infill lots.   My big take away from this experience thus far is starting to take into account the glass to frame ratio of the windows we use.  For example, it’s much more efficient to have one giant window rather than two smaller windows of the same area as the glass to frame ratio is usually better with one big window.  Anyway, yet another consideration to throw into the mix when designing future houses.

I’ll probably ramble on a little bit more about the Serious windows when we get them from Colorado in another month or so.

Project: 6th Street SW · Tags: , · Leave a comment

Foamed in

March 29, 2009 by Jeff Erkelens

Well, Weatherseal Insulation Company just spent the last two days spray foaming, caulking, and firestopping the house in anticipation of drywall. So, I thought I would take a second to talk about the various insulation strategies used in the house.

First off, let’s start with the biggest limitation: this house is a traditional wood framed house. When people think about insulation, they generally think about what’s in between the studs (fiberglass, cellulose, foam, ect), but not actually the studs themselves. For instance, a 2×4 stud wall can have an r value of 13 for the insulation, but the studs themselves have only an r value of about 4. Cumulatively, all those studs are like a big hole in your house.

So, there are great technologies out there, if installed properly, that don’t give you that thermal breakage. We just finished a S.I.P framed house (which is foam sandwiched between osb on the inside and outside). There is also thermasteel panels, superior walls and ICFs among other options.

But, again, we did not use any of these options for the simple reason of cost.  I hope as these there options gain more and more market share, the cost will come down, but it still can be a little prohibitive.  The SIP manufactures make the pitch that it is about the same cost, for the extra material cost is covered by how much you save in labor costs. But, honestly, I build relatively small houses, and the three of us have become pretty efficient in framing up a house.

Anyway, to counteract this limitation, we do a bunch of things: One is to wrap the entire exterior in 1/2″ rigid foam board, which acts kind of like a blanket over the entire house and doubles the r value of all those studs.

Another thing we do is value framing techniques, which I feel most builders around here are pretty hip to these days. I took all these pictures to show what that means, but I think I’m going to hold back on posting them as this post is probably dry and boring enough.

But, in a nutshell, it means limiting the amount of wood in the exterior wall as much as possible to increase the whole house r value of the house. Some of the strategies weuse include ladder blocking, stacked framing, 24″ on center stud spacing, insulated headers, minimized cripples, one stud corners. Again, thankfully, a lot of builders have made this the norm. 

Another consequential item when it comes to framing is that we are building are roof systems out of manufactured wood i joists (tjis). These have the same profile of a steel I joist, in which you have  a top and bottom wide flange separated by a long narrow vertical member. In the case of the TJIs, the vertical member is only a 1/2″ thick meaning the roof system has an extremely low level of thermal breakage when you spray all the foam in there.

As far as actual insulation, we have been using an open cell foam spray foam for the walls and roof. While the idea of recycled newspapers (cellulose), or recycled blue jeans (demim batt insulation) sounds cool, I just don’t think you can beat the performance of foam. Anecdotaly, our experience is the difference is night and day. Basically, spray foam expands and hardens and fills every crack and void to make an air impermeable barrier. Cellulose or fiberglass works by trapping and slowing air movement.

The only other thing to add on the foam is that not all foams are the same. To be honest, I’m still trying to increase my awareness, but we have been using a polyurethane foam rather than a polyiso as it has a much higher r value per inch.  The big thing is it maintains it’s air barrier, vapor barrier and r value properties over time. For example, celullose can settle leaving holes up top.

The product claims it is made sustainably made from renewable resources, but if you dig deeper, only about 20% is renewable (namely vegetable oil), so it seems like there is room to grow in that regard. Another reason we have switched to 2×6 walls instead of 2×4 is that we don’t have to spray the whole 2×6 wall cavity with foam to get an extremely high performance house. (Basically a 5.5″ thick wall is only 2 percent more effective than a 3.5″ thick wall at heat flow reduction). The upshot is if properly installed there should be no waste if done right. However, in a 2×4 wall, they have to overspray and then trim back the foam flush meaning you end up with all these garbage bags full of extra foam. Honestly, we did a house where this technique was used and the installer probably left with 20 garbage bags of trash, which is extremely disheartening.

When it comes to indoor air quality, I do know the foam contains zero formaldehyde, cfcs, hcfcs, hydrocarbons, or penta bde. Also, the one material I use when building a house and that most builders use is the OSB sheathing (the chip board stuff that goes on top of the studs and give shear strength) and honestly, I just think that stuff really off gases. But, by sealing in the wall cavaties with foam it should stop any offgassing to the inside of the house.

I’ll try and write a post about indoor air quality at some point, but we have a bunch of strategies to maintain a healthy house.

Alright, running out of steam. Really quickly: The Weatherseal company has had superb attention to detail on my houses, including caulking any piece of framing that touches one another as well as where framing touches the ceiling and floor to prevent air infiltration. To some extent, this is redundant in my system with the exterior taped foam board, but it’s nice insurance.

We are also using high performance low e-4 Andersen windows. The only bad thing I have to say has nothing to do with the performance but that the exterior is vinyl, which in terms of the manufacturing process, is pretty bad for the environment. Contrast that with Pella, Marvin, Jeldwen, Loewen which are all wood aluminum clad. My only defense is that I bought all the windows from two separate builders that screwed up their order (wrong color), so  I see it as effective reuse.

Lastly, the first floor has a concrete slab in order to capture, store and emit heat collected from the sun as were trying to do more and more with each house with passive heating and cooling strategies. The big thing to say about that is that concrete will slowly leach the heat. So, even though the slab is at at minimum 18″ below ground already and the exterior of the slab is completely insulated, we laid 2″ rigid foam board under the entire the slab.

The other big heat loss for concrete slabs is around the perimiter.  To solve this, we used the Superior Wall XI foundation system (www.superiorwallsva.com) around the perimiter of the house.  This precast concrete foundation has 2″ of rigid foam imbedded into it.  We then poured the non loadbearing concrete slab inside of that, avoiding any heat loss. The other bonus of this foundation system is that it is wider than our walls and is 3’6″ off the concrete floor. So, we plan on building  a little ledge on top of it around the 1st floor, which will be a great place to set drinks down or maybe have small sculptural pieces of art.

 

I think that’s it for about now. More power to you if you actually read all this. Hopefully, moderately coherent.

Cheers, Jeff

Project: Rockland Avenue · Tags: , , , , , , , · Leave a comment