Historical Architectural Details and Green Building
Tauntaun_Guts | Posted in General Questions on
What details that are common to period homes in the U.S. are simply a bad idea from a “green construction” point of view?
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Basements without footing drains.
Big wood-burning fireplaces.
Asbestos miscellaneous stuff
Assorted now-banned pesticides
....Just don't buy an old house ;)
>....Just don't buy an old house ;)
While stated in jest, with some exceptions buying an old house (and upgrading it) is generally greener than building a new one. The materials choices and methods for any upgrades makes a difference in the shade of green, of course.
On the "...details that are common to period homes in the U.S. are simply a bad idea..." list some of my favorites are :
*Large expanses of glass in mid-century modern homes, that raise both heating and cooling loads. Replacing all of that glass with higher performance glass is only a partial solution and often expensive but it's a good start.
*Flat roofs in snow country (and other zones) is another. Flat roofs can't really be vented well, and it's even more problematic with a few feet of snow up top. Insulating above the roof deck and going unvented can mitigate some of the moisture issues but it's expensive.
*HVAC ducting above the roof deck or in uninsulated wall cavities is another. (Some of that is still happening in current construction.)
^^Those issues are treatable, for a price. All three of the above were issues in a project I consulted on a handful off years ago. The ductwork & roofing issues were resolve by building a very low slope gable roof above the existing roof, with 6" of rigid polyiso above the new roof deck.)
*On homes of various vintages, siding attached directly to framing without intermediate sheathing or air exterior side weather resistant materials, which makes it difficult or impossible to air seal and insulate those walls in a moisture safe manner.
On a recent project the house had unsheathed board & batten siding some of the wall cavities had been previously insulated with fiberglass batts (a mix of R11s and R13s) and other cavities were empty. The treatment was to dense-pack all cavities (including dense-packing over the batts) with cellulose, stripping the battens then installing a fully adhered weather barrier (in this case Henry Blueskin VP100) onto the wide plank siding further improving air tightness, then installing new cedar shingles over a 1/4" mesh-type rainscreen (Obdyke Rainslicker Max, in this instance.) There is still work ongoing on that project (even though the house is fully occupied), and I don't have the final blower door tests, but it made a HUGE difference in both indoor comfort and energy use, for well under the cost of building a new house.
*Homes heated with fossil fuels. Clearly this is still ongoing, but becoming more technically possible and affordable to retrofit every day. Going forward it's somewhat irresponsible to use fossil fuels when there are heat pump solutions that work for the climate.
I'm currently consulting on a retrofit to a small-ish circa 1930 house (in surburban Boston, climate zone 5A) where they are likely pull the gas meter after they upgrade the kitchen. The original hydronic boiler was still in service up through last spring, but was ripped out over the summer during renovations. A 2-ton ducted mini-split is going to be installed before the end of next month. As with many older homes, this house was originally uninsulated, but had some wall insulation (fiberglass batt insulation) installed over the past century during repairs and renovations. Working under a state sponsored rebate program the cellulose installers balked at dense-packing over the batts, even when the owner was willing to pay full freight (off-program). They will be returning next week, and I've recommended that the owner press them on it again. If THEY won't do it, someone else will (even if it's me- it's a small enough house to dense pack the whole thing by myself in less than a weekend.)
Not every "...old house..." is worth fixing, but many or even most are. There is almost always much better bang/buck and bang/net-carbon to fixing what exists rather than building new.
I could turn this into a post for GBA, if you are amenable. Of course, it would be your byline. It's such a good question, and your answer is excellent. I'd love to share it more widely. Let me know.
> with some exceptions buying an old house (and upgrading it) is generally greener than building a new one.
I'm jaded by being in deep on my project and continually running into new issuesm but I increasingly feel that I may have been one of the exceptions -- or at least walked myself into being the exception :P
Renovation isn't without its costs either -- I've taken what was nominally a functional house, albeit dated and in need of a few repairs, and, at a quite substantial cost in both money and time, will be left with a result that will inevitably be better than most houses of its age, but not as good as the same amount of money and time could have likely made a new structure. In the process, I've sent at least 120 yards worth of dumpster to [a hole in the ground somewhere else where it's now someone else's problem] -- not counting the salvageable stuff that's gone to re-use here or elsewhere -- and expended time and materials (LVLs, polyiso foam) that wouldn't have been necessary save for the constraints imposed by an old structure.
In the meantime, a new, huge, probably code-minimum build went up on an empty lot down the street. I can't help but think -- there's a fixed number of houses, and people who need houses, what if I had gotten the lot and built a new house, and someone else had done some minimal renovations and otherwise left my house as it is? I certainly wouldn't have built as large of a house, and likely would have built more efficiently, so the net environmental cost may have been less [not to mention my stress levels ;)]
Of course, the greenest decision I could have made a couple years ago would probably have been to stay in my old apartment...
I guess what I'm getting at is -- it's complicated. It'd be greener to not build any new houses, especially single-family detached houses in the suburbs -- but population is growing and there's a demand for this type of house. If a house is bound to be built it seems it'd be better if someone green-minded were to build it.
>I guess what I'm getting at is -- it's complicated.
That's right! And you don't know when embarking on a project exactly where it's going to take you or what the dollar cost will be. It's usually easier to budget a new build.
If all you are looking at (and I'm not implying that you are) is resale value returns or the net present value of future energy savings, beyond air sealing and right-sizing any necessary replacement HVAC green retrofit upgrades are rarely a great inve$tment. But if you're living in that older house turning so-so comfort (or downright UN-comfortable) dwellings into something ultra comfortable with great indoor air quality comes with a lot of satisfaction.
That said, despite spending well north of $100K to fix that mid-century modern home, (not counting the office space that was added over the garage) turning it into the most comfortable home the owners had ever lived in was "worth it" in it's own terms, and when selling it after only ~5 years of living there (now empty nesters, big house) they even MADE money on it, and that was before the recent real estate price boom. Of course it's a nice house in an upscale neighborhood, and not everybody has that kind of cash to play with, but they did right by their fairly short stewardship of that place, a place that had been pretty miserable for ~50 years.
Of course had they held onto it for another year they might have made even more- check out the price history on it due to market conditions:
Clearly not every retrofit would have that kind of ROI.
The place is still cursed with Martin's "Big wood-burning fireplaces.", on both the lower and upper level, (basically an energy hole) but the diffuser selection & placement as well as right-sizing the HVAC compensated well for what might have been cold-draft inducer when not in use. By right-sizing the HVAC the fireplaces never became a comfort problem. The prior heating plant had been a 200KBTU gas boiler, with slab radiant heat on the lower level, ceiling radiant (with a barely insulated roof) above. The cooling was separate 5 ton AND 4 ton commercial building package units & ducts above the roof- a total energy & comfort disaster (but they satisfied the thermostats), and deafening while running. Even after adding more square footage to the house, with all the HVAC mechanicals in the cramped mini-hobbit crouch-attic of the low sloped insulated gabled roof they ended up heating with a 2-stage 60KBTU/hr gas furnace and a 3 or 4 ton AC (I'd have to look it up- my memory isn't perfect), and it is difficult to tell when it's running unless there is no wind, and nothing else is running in the house.
Narrow footprints, small rooms, short ceilings.
Agee that tearing down a house is the ultimate in non-green. Buildings get torn down for the most part because they are functionally obsolete, not because they can't be fixed. A lot of old buildings don't have layouts that would be appealing today, and can't be changed in a practical manner.
Complicated roof lines, half story construction, dormers, bay/box windows and cantilevers. It takes a lot of attention to detail to get any of these right and very easy to build them incorrectly in any new construction.