Mind the Gap

Jeff bought his home in the middle of summer several years ago. The first winter, a gap opened in the drywall between the gable-end wall and the vaulted ceiling. The gap seems to close every summer and open again every winter. Jeff hired PERCH to diagnose the problem and recommend solutions.

What on Earth was going on here? My initial investigation ruled out several possibilities. The gap is seasonal, not progressive (although Jeff does think it gets worse each year), so it doesn’t indicate a problem with the superstructure but something environmental. Frost heave seems unlikely, as Jeff has no uneven floors or major cracks elsewhere in the house.


The gap between gable-end wall and ceiling.

For a little while I was wooed by the idea of truss lift. Roof trusses are known for expanding and contracting in cold climates: in winter, the bottom chord stays warm and damp because of its exposure to inside air, while the top chord and webbing gets cold and dry right below the roof. The top chord and webbing contract and pull up the bottom chord. But Jeff with his vaulted ceiling clearly doesn’t have roof trusses. They must be rafters, no deeper than 2×6, for which any differential contraction would be barely visible.

The best-fitting explanation was not frost heave, but a different kind of heave. Certain soils (typically soils with a lot of clay) are known as expansive soils because they collect groundwater and expand during wet seasons, then lose the groundwater and contract during dry seasons. If the gable end wall was built on an expansive soil, it would tend to drop in the winter and rise in the summer.

But wait. Wouldn’t the rest of the house move, too? I found evidence to the contrary during my site visit. On the first floor, a wall adjacent to the offending wall had a few minor cracks in the drywall. Directly below, in the basement, a crack ran across the plaster covering the concrete foundation. Aha – the walk-out side of the basement is framed by a stud wall, which is much lighter than the concrete walls on the other three sides. The soil under the stud wall hasn’t compacted as much as in the other locations, so it’s more susceptible to subsidence when the soil contracts.


Cracking in the first-floor wall, about 6 feet from the corner.

Sometimes structural engineering is like solving a mystery. I search for clues and weigh possibilities against the evidence, and hitting upon the right answer is very rewarding.

“Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.”

Sir Arthur Conan Doyle

Tiny Tuesday: Man Cave, She Shed

Hobbies take up space, and Americans so love carving out extra room that we’ve named the result. First it was guys who aspired to build a man cave, converting a spare room into a place where they could play video games or sip scotch or do some other stereotypically guy thing. More recently, ladies who wanted space for sewing or gardening (to continue the shameless gender pigeonholing) settled the gender imbalance by coining the she shed.


A garden shed becomes a pink place to pot plants and put your feet up. (flickr – creative commons)

In either case, the fantasy is to repurpose an underutilized space into a useful one. (Some folks custom-build additions or outbuildings for their man cave/she shed, but that I think goes against the spirit.) You might start with an unfinished basement, a forgotten garden shed, an attic over the garage, or a guest room that has become the de facto storage room. A fresh paint job, thoughtful organization, and the right furniture can make it personal and useful.


A man cave made from a metal hoop house. (flickr – creative commons)

The completed room, whatever it is, functions as a grown-up version of a fort or playroom – a private retreat where you can do what you like without distraction. One way to live a tinier life is simply to make better use of the space you already have. Whether you call it a man cave, a she shed, or something less trendy (“workshop?”), it’s nice that we as a culture have put a name to the trend.


Farmhouse-style storage in a she shed. (flickr – creative commons)

Thanks to Jas Smith for giving me an excuse to put up some cool inspiring pictures.

Tiny Tuesday: Wheel Pad Makes Your House Accessible

By and large, the world is challenging for wheelchairs. In public settings in the US, new construction and renovations must conform to the Americans with Disabilities Act (ADA), which specifies ramps, elevators, and 5-foot turning diameters to make the buildings accessible to everyone. But private homes aren’t bound by the same standards. That means many people faced with mobility impairments come home to entry stairs, tight bathrooms, and other hazards that may cost a fortune to retrofit.

Enter the Wheel Pad. Designed as a temporary extension of an existing house, the Wheel Pad has a bedroom and bathroom with ADA-standard clearances, a Hoyer lift track built into the ceiling, an entry ramp, and a door to connect the unit to an adjacent house. All this comes in an ultramodern 200-square-foot package on wheels. It’s a novel use of the tiny house concept, and in hindsight a pretty obvious one. Why did it take so long for someone to market this?


Inside the prototype Wheel Pad. Note the Hoyer lift track built into the ceiling.

That “someone” is a group of architecture students and professors at Norwich University. The prototype Wheel Pad went to a southern Vermont woman who recently became paralyzed from the chest down, and future units will be sold for $60,000 or leased for $3000/month. Since a unit is highway legal, it qualifies as an RV for zoning purposes. A septic tank is built in; water and electrical supply come from the existing house.

Physical access to the existing house is unclear, although the Wheel Pad website says illustrations are available for buyers. Can the entire unit be lifted higher or lower to match an existing door, or must a driveway be built to the correct height? (Settlement could make the latter pretty untenable for long-term accommodation.)