frontstepdesign

Review of Osae-Addo House coverage, Dwell Sept '07

I was pleased to see one redeemable article in the 1/2" thick sellout that comprises Dwell Magazine these days.  (Please, stop sending me this landfill doorstop.)

It's about a couple who move back to Accra, and build a house specially designed to deal with HOT, HUMID weather.  Rather like our 93d, 90% humidity days this last few weeks.

I thought I'd list off a few strategies that Joe Osae-Addo incorporates in his house (near as I can tell from photos) and record what I think of them.

First, a GREAT quote:

"Interstitial spaces and landscape are what defines tropical architecture...It is not about edifice but rather harnessing the elements - trees, wind, sun, and water - to create harmony, not the perfection that modernism craves so much." ~Osae-Addo

That's Hero-worthy, that is.  Architecture not about edifice.  Hallelujah.

Onto the cooling strategies that I think are a good idea.  These will be followed by the red herrings (*).

1. The house has no internal corridors, allowing air flow and cross-ventilation to occur whenever you're lucky enough to get a breeze.  Also allows daylighting.
2. The house is surrounded by a deck and deep eaves, that shade the walls/windows, and protect the foundation from washout.
3. There are slatted sliding shades on the deck itself, offering opportunities to create shaded breezes.
4. The house's floor is raised about 3' off the ground, making the crawlies really invest in any hope of future return.  The article says this elevation also 'takes advantage of cooling breezes'* and 'provides access to the electrical and plumbing underneath'*.  Perhaps theoretically.  See below.
5. I see high ceilings in the photos, and white walls to reflect the shaded light.  Also ceiling fans, and high windows to let heat out where it accumulates.  I also see a floor-stand fan, and a water dispensary, and the people shown in the photos do 'glow'.  It may be cooler, but it's not US definition of cool.  That's okay.  I see little carpet - what's there looks like sisal - and surfaces look designed not to absorb moisture, shiny waxes, polyurethane, etc.  All good.  Think boat.
6. Shade trees.  Very effective.

Okay, here are the 'features' that prove the author of the article has little experience with heat/humidity as a lifestyle.

• Elevating the floor to 'take advantage of cooling breezes.'  Coolth sinks, bub.  You crawl under your house, it will be nice and cool under there.  If you're running air conditioning at all, you will lose some out the inevitable leaks in the floor.  Constant battle at my house with the sealant gun.
• Elevating the floor to provide access to systems.  This is wishful thinking.  3' minus the thickness of the floor system gives you just enough room to slither under there and say - yup, that's where the drain is.  It doesn't give you any elbow room to actually work.  Even a power drill is difficult.  If 'providing access' is your goal, start with 5', grade-to-finish-floor, and 8' would be better.  Don't worry, the pipes won't freeze.  Then you can hang out under the house, like they do in Australia.
• The house brags about its jalousie windows, and that they're used floor-to-ceiling.  This is great for cross-ventilation - but jalousies are horrible for keeping out (1) bugs; (2) humidity; (3) air leaks.  If you have any plans at all for HVAC - don't use them.  Use a double- or triple-hung instead, with the top sash as close to the ceiling as possible, to let out heat.

Because I can't end on a downer, I have to (reluctantly) applaud Dwell for addressing heat and humidity together.  I rarely see that combo in the mainstream media, yet we're all going to be seeing more of it in the coming years, I feel sure.  Also, I like seeing a focus on lessons to be learned from the non-First World, even if we have to follow ivory-tower academics from LA to get there.  Sigh.  Always a compromise, in this life.

(Confidential to KB - your email addy keeps bouncing my replies.)

Making the house less hot - walls

Our house has no insulation inside the walls.

It has foil-faced polyiso board installed under the siding - R value of approx.7.20/inch.  Nothing but air inside - which has an R-value of 1.  If I use this table, the R-value of our walls is currently:

Outside air film - 0.17
Siding, hardboard - 0.34
Foil-faced polyisocyanurate board - 7.20
5/8" plywood - 0.77
3.75" air (old studs) - 1.00
1" plaster - .45 x 2 since it doesn't have plaster in the table
Inside air film - 0.68

Total wall R-value = 11.06  That's not awful.  University of Central Florida says wall insulation is not that critical for Florida.

InsulAdd paint coatings says their products can increase the effective R value of a wall by 20%, which would beFor a cost of $175.00/5 gal./250 sf/gal for the RBC Radiant Barrier Coating, applied as primer, and $130.75/5 gal. /275 sf for the Insuladd Insulating Additive mixed into house paint as finish coat.  The outside of our house is 1312 sf, approx, not subtracting openings.  So that's 5 buckets each, for a total materials cost of $1530.00. 

All of that is supposed to reduce our AC-heat bill by up to 40%, which at an average monthly cost of $105, would be $504/year, and would pay for itself (materials only) in three years.  It's also supposed to outlast ordinary housepaint, so I could wait until I build the addition and need to paint it, then paint the whole compoound.

Alternatively, I could drill holes in all my walls and have Icynene or BioBase foamed in between the studs, which would supposedly add R12 to the walls, at a cost of $2/sf (materials), or $2624.00.  I don't remember how to figure the cost savings there.  Perhaps a trip to the library to visit my old HVAC book is in order.

Making the house less hot - Windows

My office is a scorcher.

It's literally the old front porch of our house, enclosed long ago, complete with siding.  Three 27" x 43" windows face east, exposed by the gable above them.  My neighbor's giant live oak tree is just out of reach...I bake in there this time of year.  I've dealt with it by putting weatherstripping on the two interior doors that connect to the dining and living rooms, and try not to be in there in the morning.  Even in the winter, when the warmth is welcome, I have to wear sunglasses to work at my computer.

So when both Treehugger and Hugg listed Sunblox solar screens, I was interested.  I've sent them the following dimensions:

  10 windows, sized as follows, in black fabric with white frames and midspan horizontal spreader bar:

 

3, at 27"w x 43"h - my office, faces east.
2, at 23"w x 52.5"h - the living room, faces south, with 2' overhang
1, at 47" w x 52.5"h - also the living room
4, at 39"w x 52.5"h - the front bedrooms, which also bake under a gable = no overhang, but we hardly ever go in there...it's too hot!

I know I will get something for the eastern sunroom.  Awnings aren't practical for hurricane alley, and that location would conflict with the driveway traffic anyway.

The above is roughly 115 sf.  If this stuff comes in at $6/sf, that's $690 total.  Our averaged electric bill is $105/month, with the a/c running about 6-8 months a year.  So if it cuts the cooling load (30% of electric, according to the local utility, but hopefully more of mine since I use all CF bulbs, have nearly all EnergyStar appliances, and am Phantom Load Nazi) by 30%, that's $11.60/month or more. (More because I'm using their percentages; I haven't got mine charted out yet.)  So that's a payoff in 59 months, or 5 years.

I really need to figure out what our monthly consumption truly is.  Time to liberate the elec bill from my dear husband.