This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
Next in order will come the raising of the exterior vertical frame, and in this relation we will have had a choice of two principles. The first and more common method is called the "full frame" or "braced frame" and consists first, of erecting at the angles of the building, posts 4 X 6 or 4 X 8. Between these uprights, at the level of the floors, are run horizontal "girts" which receive the joists of the second floor and into which are framed the door and window studs, and at the top of the wall a plate is set in a similar fashion. The angles made by these timbers with the posts, are braced by diagonal pieces framed or spiked to the horizontal timber and post. (Fig. 22.)
In the other method of exterior framing, called " balloon framing," the girts are omitted and the studs run from sill to plate. The usual way of forming the plate in this construction is to spike on the top of the studs a 2 X 4-inch piece, and on top of this another 2 X 4-inch piece, breaking joints and overlapping at the angles.
Provision for supporting the intermediate floors is made by spiking a board 1 X 6 inches into notches cut in the inside of the studs so that the top of the board will be an inch above the bottom of the floor joists. (Fig. 23.) This board is called a ledger-board and is one of the weak points of balloon framing, not in the weight carrying sense, but in case of fire, as it does not prevent the spread of the fire as would a solid girt, being more easily consumed and doubtless would let the floor fall. The floor joists should be notched over this ledger-board, which should be kept back a little from the inside face of the studs to allow space for the mortar to clinch. Another weak point is the omission of braces, which if used can only be short ones at the top and bottom, and are usually omitted in this kind of frame. A substitute for braces sometimes used, is a stout strip usually one inch by three inches cut diagonally into the outside of the studs and spiked to each. This makes a very strong brace but weakens the studding. The fact that the studs of a balloon frame run from top to bottom, requires that the windows should be as nearly as possible over each other so that one set of window studs will serve for both upper and lower windows. The erection of the outside frame should be carefully watched to see that the door and window studs, at least, are tenoned head and foot, that all the braces are put in and properly framed, and that all the joints are snug and well pinned, the openings in the proper places, and the framing plumb and rigid. Nothing is more annoying than to find, after the outside frame is all up, that a window or door has been framed out of place, and although the builder may be obliged to rectify the mistake at his own expense, it can only be done by patching somewhere and the owner is quite likely to feel that the error might have been prevented by the more careful oversight of the architect. As soon as the frame is set up, in our case a full frame, which can be set up a story at a time (the attic joists only being carried on a ledger), the outside boarding is put on. Spruce or hemlock is used for this mainly, but it must be mill-planed to an even thickness so as to give a true surface for the outside covering of clapboards or shingles. (We find that the boarding is specified to be matched and laid diagonally upon the walls and square-edged for the roof. The reason for not matching the roof being that the cracks in the square-edged boarding will allow circulation of air under roof shingles and preserve them much longer than if matched boarding were used.)
Fig. 22. Brace.
Fig. 23. Ledger Board.
When the first story studding is set and the girts are on, the inside bearing partitions must be set up to give a support for the inner ends of the second floor joists. It will not be necessary to set up all the studs of these partitions at first, but the partition caps should be run and studs set up at three or four-foot intervals and set as nearly as possible in their proper places, to avoid doing the work over again. As soon as this is done the second floor joists can be set and bridged and, with the outer walls carried up to the plate and another partition in the second story set, the attic joists may be put on and the building made ready for the roof. At this juncture we are approached by the foreman who holds in his hand a smooth board upon which he has drawn a sketch of the attic joists and ledger-board which he submits for our opinion. We examine his drawings and find that he has represented a ledger-board 2 X 3 inches notched into the studs one inch and up into the joists two inches, making the bottom of this ledger flush with the bottom of the ceiling furring. (Fig. 24.)
This method he puts forth as having nearly equal strength of the 1 X 6-inch which is generally used, and the merit of not presenting so broad a surface behind the lathing at the top of the second story, which destroys in a measure the key of the plaster. We consider carefully all of the features of this method and admitting that it has these features to recommend it, we can praise the ingenuity of the device. If we were to run heavy cornices at the top of our second story we would be inclined to adopt the sketch, but as we shall run only a picture moulding in the angle which will be helped rather than hurt by the presence of the wood behind the lathing at that point, we decide in favor of the usual way of putting in the 1 X 6-inch ledger, but tell the foreman to notch the studs 1 1/8 inches deep so that there will be a space between the laths and the ledger for a key to the plaster. (See Fig. 23.)
Fig. 24. 2" X 3" Ledger.
An important matter in carrying the outside and inside supports from bottom to top is to see that the amount of shrinkable timber is as nearly as possible the same in both outside and inside walls. For this reason the common practice of setting the partition studs upon a horizontal piece laid on the under floor should be avoided.
(Fig. 25.) For instance, in our case the amount of horizontal wood in the outer wall from the rigid underpinning to the bottom of attic joists will be,the sill at six inches, the girt at six inches and the upper part of the ledger board above its nailings at two inches, - in all fourteen inches of shrinkable wood. If the inside partitions were set on a two-inch sole resting on the under floor in each story, there would be in the inside wall, from the rigid piers in the cellar to the under side of the attic joists, - the girder at ten inches, the two tiers of floor beams with under floors at eleven inches each, and two soles and two caps at two inches each, - making in all forty inches of wood, the shrinkage of which would amount to an inch and a half or more as against a probable half-inch on the outside walls. The result, when the house has become completely dry, would be that the inner end of the floor beams would be an inch or more lower than the outer end, enough to crack the plastering, and make doors bind in the cross-walls of the second and third stories. The remedy for this, is to let the studs of the first story stand on the girders, and the studs of the second story stand upon the cap of the first story partition, and so on, so that the floor timbers do not form a part of the vertical frame. (Fig. 26.)
Fig. 25. Wrong Way of Setting Partition.
Fig. 26. Right Way of Setting Partition.
This will give an amount of horizontal wood equal to the girders at ten inches, and the two caps at two inches each, making fourteen inches in all, about equal to the horizontal timber in the outside frame. Partitions running through two or more stories which do not carry floor beams should be built in the same way. Partitions which have no corresponding partitions under them will often occur and will be found in two conditions, those running parallel with the floor beams and those running across the floor beams. In the former case it will be necessary to set two floor beams under the partition spaced far enough apart to give a good nailing for the ends of the upper floor boards. In the latter case it will be necessary only to lay down upon the under floor a sole two inches thick by the width of the studs.
An important matter in relation to the levelling of the floors is to see that all measurements for sizing down of the timbers are made from the top of the timber, so that the floor will be level on the top and any inequalities in the depth of the joists can be taken up in the furring. A half-inch will usually be enough to overcome the differences in the depth of the joists so that a series of ten-inch joists should be set with their tops nine-and-one-half inches above the girder or partition cap upon which they rest.