Ex1.3 - Wood Platform Framing

This web site is from a good course at Cornell currently being taught in construction technology. It provides a general overview of the history of wood construction.

We now have a concrete slab in the ground that is 24ft by 24ft with a 12ft by 12ft "dogleg" on its east-northeast side. The 12 by 12 area is the stairwell space for a simple switch-back landing stair set. There will be no second floor in here.
NOTE: Consult the Architectural Graphic Standards or Thallon's Guide to Wood Frame Construction or Ching's Building Construction Illustrated for standard wood frame building practices and then, with express permission of the contractor, visit a residential construction site that is just completing the wood frame construction phase and see it for yourself. Seeing it in diagram, seeing it in situ, take photos of specific details, and then drawing and modeing in it is the best way to comprehend a construction system quickly. It is not a question of learning it in class. It should be a matter of desire to practice professionally that you should understand and be able to construct space through the various common construction types in our region- steel frame, tilt-wall concrete, pre-engineered metal frames, CMU masonry walls and bar joist roof, platform framing in wood, cast-in place concrete, and others. At this point we are focusing on the structural systems and not so much the methods of enveloping and climactic performance in the construction system.

Model the dimensional lumber on the slab for a two story platform framed structure as such:
1) Difference a 2 by 2 (nominal dim.-actual 1.5" by 1.5" dim.) strip out of the outside top edge of the perimeter of the concrete slab. Set the concrete slab with removed perimeter strip on a layer called "Slab".
2) Along this 1.5" set back on the top of the slab run a continuous 2 by 6 (again nominal dim.) bottom plate for the perimeter walls.
3) Set 2 by 6 (nominal dim.) by 7'-7.5" tall studs at 16" on center (o.c.) on top of this perimeter bottom plate. Check standard practices in the texts and on site as to how you should make the studs turn the corner.
4) On top of this range of studs lay a 2 by 6 lower top plate.
5) Lapping the first top plate at any cut (so as to bundle the constructed walls together), set a second (upper) 2 by 6 top plate directly on top of the first top plate. The top of this second plate should be 8' tall off the concrete slab. Put all the elements in steps 1 to 5 on a single layer called "1st Wall".
6) Around all the outer perimeter of this wall STAND a 2 by 12 (actual- 1.5" by 11.25") floor plate so that the outside of all the dimensional lumber in the assembly is aligned "flush out". Run the floor plate on the eastern edge of the 24 ft by 24ft box from the southeast corner 24ft north, including across the opening to the northeast corner. Double this floor plate with a second piece just inside the first. This doubles up the wood making the beam over the 12ft span.
7) Running east-west, set 2 by 12 (actual- 1.5" by 11.25") floor joists spaced at 12" o.c. from inside of floor plate to inside of floor plate. Put all the elements in steps 6 and 7 on a single layer called "2nd Joists"
8) Using 4ft by 8ft 3/4" thick plywood sheets sheath the top of the floor joist structure over the 24ft by 24ft area with a plywood sub-floor. (It is called a subfloor because something will cover it to make the finished floor.)
BRING THIS MUCH MODEL TO THE BEGINNING OF CLASS ON THE DATE YOUR TA REQUIRES IT. YOU WILL MODIFY THIS MODEL AND TURN IN YOUR WORK AT THE END OF THAT CLASS.

IN THAT CLASS WITH YOUR TA:
9) Around the perimeter of the north, east, and south sides of the 12ft by 12ft stairwell block out the perimeter floor plate so that the inside face of the assembly is aligned flush along the inside. Cap this blocking with a layer of 3/4" plywood so that the tops of these wall assemblies are as high (flush) as the subfloor on top of the 24ft by 24ft area. Put all the elements in steps 8 and 9 on a single layer called "2nd Floor".
10) The landing is a 4'-5"(n-s) by 10'-10" (e.w) platform blocked out and hung from the surrounding studs made from 2 by 8 floor plates and joists (running north to south) and covered with a 3/4" thick plywood subfloor so that the top of the subfloor is 4'-6" above the slab.
11) The steps have 6.75" risers and 12" treads. The treads are 1.5" thick. There is no kick plate (riser piece). There is a run, a straight line of stairs from ground to landing, of 7 steps; the landing, which is step 8; and a run of 7 steps from the landing to 6.75" below the second floor. The edge of the second floor is considered the last, 16th, step. These two runs are each 5'-5" wide and have a stringer on each edge cut from a 2 by 12. Put all the elements in steps 10 and 11 on a single layer called "Stairs".
12) Copy the first floor wall and move the repeat so that the bottom of the bottom plate is set on the second floor subflooring. Put all the elements in step 12 on a single layer called "2nd Wall".
13) Copy the second floor plates and joists and move the repeat so that the bottom of the plates and joists are set on top of the double top plate of the 2nd walls. Put all the elements in step 13 on a single layer called "Roof".
14) Remove stairwell blocking copied to the roof structure and extend joists to connect to the east edge of the 12ft by 12ft stairwell structure. Set 3- 2 by 12 beams side by side that span north-south and rest on the N-S walls supporting these lengthened roof joists from below at the 12ft by 12ft stairwell opening to the 24ft by 24ft space.
15) Revise the second floor plates and joists, the second floor walls, and the roof so that the second floor projects west in a 6' cantilever. Set 3- 2 by 12s side by side that span north-south and rest on the N-S walls under the roof structure at the stairwell opening to the 24ft by 14ft space to support these lengthened roof joists.
16) Adjust the 2nd floor and roof structure so that the roof slopes from west (highest side) to east (lowest side). To figure these heights make the bottom of the support beam in step 14) at7'-0" above the second floor subflooring and set the bottom of the support beam in step 15) at 9'-0" above the second floor subflooring.
17) Save the file as 3341_Sect0XX_XXX_Ex1-3.fmz and submit this at the end of class.

This assignment is arranged so that students who are not familiar with the contents of their files will be penalized. Make sure that you make your own work before class. If you don't you won't pass because you won't know how to manipulate it and turn it in by the end of class.

Cutting Corners

We realize that you all are currently doing identical work. This will form the base of what you'll make in the next two weeks as you demonstrate material techniques in Wood, Masonry, & Steel.

Each step is designed to lead to the next- additive & incremental learning. If you skip over one step & use someone else's work you'll inherit their mistakes & your own ignorance of the nuances of the construction. You won't be able to make a structure unless you know the foundation, site, & spatial issues this step raises. This is the moment we inscribe the project's spatial arrangement parameters into the site & build a foundation to build upon.

We begin a construction by inscribing space into the site & we materialize the building through our authorship of the parameters of this inscription.

This is the most critical step of the modeling exercise.

Space Sketches for Ex.1.2

Siting & Foundation Sketches for Ex.1.2

Form•Z Purchasing

For those of you who will use Form•Z this semester you can get it HERE on-line.

Text Books

There is no required text but we strongly recommend that you quickly get the 4th edition of Building Construction Illustrated by Francis D.K. Ching. It is an excellent professional resource and can be had for as little as $20 on line. If you decide to buy an earlier edition of the book you will get the same basic information but the page references we give may be off. You can get the 3rd edition for as little as $10 on line.

The book is on reserve and in permanent reference in our library but this is one book that is affordable and makes an excellent reference book for you to keep.

The other reference book, Architectural Graphic Standards, is a great book to have but it is $188 on Amazon. We have electronic versions and paper versions of this book on reserve in our library for those of you who don't have a free $200.

These are both books you'll never read but will refer to for the rest of your professional career. They're not glamorous but they are invaluable. If you can't afford the later now, remember to ask for it at Christmas and/or at graduation. They're both worth their weight in money for understanding normative construction practices.


Links to the library reference page for both of these books are available to the left.

Welcome!

This will be the general course web page for ARCH3341. Particular sections will have their own web page. This will remain the base page for the semester.