BEFORE THE ARCHITECT – THE BIG PICTURES

RESIDENTIAL DRAWINGS –

MAJOR PLAN SETS, FRENCH COUNTRY

PLAN DETAIL - 2 OF 2, GENERAL SPECIFICATIONS

General Design and Construction Specifications, in PDF

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Here, we have the general introduction to our house design and construction plan. Information on this sheet is broadly applicable across most aspects of this plan set.

This is a summary of this sheet's contents:

A. Design specifications, essentially environmental, to guide the choice of construction materials and their applications, such as wind and watershed load indicators, metrics for cooling and heating, etc.,

B. General specifications that won't need more specific references in most cases, Included among these are precedence of authority in case of confusion or conflict in working with the plans themselves and the construct, sealing the building envelope overall, etc,

C. A hand-framed span table to the right of Genghis Kahn. The AG developed this span table with the help of Frank Woeste, Ph.D, P.E., Professor Emeritus at Virginia Tech. The AG likes sturdy structures, reasonably overbuilt by low, contemporary common standards. In truss floor framing, for example, the AG's distinctive standard is a deflection limit of L/480 under a 60psf live load and 20psf dead load. The AG had no similar table available for hand-framed floors of dimensioned lumber, until Frank Woeste answered the call. The rest of this span table reflects that conservatism.

D. A truss-framed set of specifications here that's meant to deliver a highly durable, extremely convenient structural shell for a residence. Among the harder points here is the stricture - as with hand-framing- that no member shall be spaced on center greater than 16". Builders like to cut costs by stretching both floor and roof framing to 24". Buyers like the lower cost, and mostly haven't the sense to know what they give and what they get. They give away strength to stresses both at points of time and over time and they get a relatively deficient structure which, especially in the finishing, will show you the meaning of cheap if there aren't sufficient offsets in other, better materials and the labor to apply them.

Here's what the AG's meaning. Recently, he read that a builder was puffing proud to have cut the cost of a roof framing job by setting rafters at 24" on center, using 5/8" thick sheetrock in lieu of the more common 1/2", therewith offsetting interior ceiling wallboard pillowing (sagging for too much space between fastening surfaces particularly (but not necessarily only) when ceiling insulation weight is added onto the topsides of the wallboard in finishing). The builder didn't make a point that the 5/8" product is marginally harder to hang - read: more labor - and its just a little bit pricier. And the builder also didn't mention at all that unless he goes to 3/4" roof sheathing from 1/2" or even 5/8" there'll be more pillowing on the roof deck, an observable failure you and all others who pass that way will witness every day and a problem the remediation of which is sky-high in cost ..... many, many times more than doing it right the first time, i.e., not laying-in wood structural members at 24" OC.

E. This area schedule is an aggregate of subsequent area schedules and data for L0, L1, and L2, separately. Note that distinction is made between managed air space and unmanaged, or open-to-atmosphere, space. This is one of many prompts throughout a plan set that offers a distinct perspective on space definition, physical association, capacity, special considerations, etc. See how the unvented crawlspace square footage dramatically increases an already large interior, air-managed surface area.

F. The thermal table is tough. For its locale, R-values are marginally higher than most would build theirs there these days. Not much, but some.  Without high-density insulation batts, InsulTarp, and the like, these R-values could be difficult to meet or exceed.  The Oak Ridge Laboratory's prescripts are based on several specific criteria about a given structure, besides its geographical location. Implicit in the Oak Ridge algorithms is the expectation that you'll design at not less than 2"x6" for exterior stud walls. Of particular import in this table: if we build an unvented crawlspace, we needn't insulate the L-1 floor above it.

G. This generic cross-section is from the AG's viewpoint more feel-good than do-good, but it's almost universally a requisite. At its best, a generic cross-section offers contractors an idea of specified layering and a set of prompts as to the association and number of building parts to a subsequent construction.  At its worst,  it can suck up big time just drawing it, and rarely are two exactly alike in custom home design and building.  Indeed, most often, wall sections - as with foundation sections - vary from place to place in most structures.