Twelve swaps
Twelve ordinary building details, each beside a version that can be taken apart again, with what it costs and what to watch for.
what is it made ofDesigning a building to come apart sounds like an expensive philosophy. In practice it is a short list of substitutions. These twelve cover most of a wood-framed building. Each one is a detail to be drawn, built, timed and priced. After that, it is no longer unfamiliar work.
This is version 0.1 of our own list. We publish it knowing that some rows will turn out wrong.
| The usual detail | The swap | Cost | Watch for |
|---|---|---|---|
| Subfloor glued and nailed | Screwed down over a rubber gasket or mat | A little more labor | Squeaks and bounce |
| Sheathing fixed with ringed nails | Smooth nails, with the sheathing treated as the part you will lose | None, if the nail is simply specified | Screws need an engineer’s approval |
| Siding nailed to the sheathing | Clipped or screwed to battens over the weather barrier | About the same | It also drains better |
| Spray foam insulation | Mineral wool batts or blown cellulose behind netting | Often cheaper | The airtight layer must be separate |
| Roofing membrane glued down | Mechanically fastened over a slip sheet | About the same | Wind uplift; warranty terms |
| Brick in cement-rich mortar | Lime mortar, or dry-stacked with ties | Similar material, more skill | Limits on strength and exposure |
| Wallboard taped and mudded | Screw-fixed boards with open joints, or a demountable system | Higher at first | Fire ratings must be checked |
| Ceilings glued or taped | Lay-in or hook-on panels | About the same | Sound |
| Welded steel connections | Bolted connections | Depends on the fabricator | Earthquake detailing and approvals |
| Concrete topping bonded to the floor | A floating topping on a slip sheet, or dry panels | About the same | Sound, and how the floor acts as a whole |
| Pipes and wires bored through the frame | A dedicated service cavity or raised floor | A little floor area | Makes the house tighter |
| Window sealed to the sheathing | Window set in a shop-built frame on compression gaskets | A moderate premium | Water at the frame |
How to read the list
Half the rows cost about the same or less. For most of the others the extra is small, and much of it is the cost of doing something for the first time.
Two kinds of wall resist all of this, for good reasons. Walls that brace a building against earthquakes and walls rated for fire are tested as exact assemblies. We accept that those stay permanent, keep them few and write down where they are. Saying so plainly is what makes the other rows believable.
The glue was often doing a different job. Look closely and the adhesive is silencing a squeak, stopping a draft or hiding a gap. Each of those jobs has another answer.
When glue can’t be avoided
Stick it to something cheap. Bond the flooring to a thin underlay, not to the structural floor. Bond the roof membrane to a cover board, not to the deck. The glue stays, but the loss moves to a part worth a few dollars.
The test
The only honest measure is a stopwatch. Build one bay of the wall, take it apart, and time it. We plan to do exactly that with each of these, and to publish the times, including the ones that embarrass us.
Drafted with AI assistance from Viridian's working papers and detail guides, then read, corrected and approved by Keith Cash, co-founder. Found a mistake? Tell us.