Part 2

Concrete piers are not hard to make. Their size will depend on how deep you must dig to reach solid earth or rock. First, build several tapered box forms of rough lumber. (Fig. 4.) These should be about 24 inches square at the bottom and taper to about 12 inches at the top. The taper makes it easier to get the forms off the finished concrete. Pour a footing of concrete at least 10 inches thick and six inches larger than the bottom of the pier on all sides. Then set the form for the pier on top of this footing.

A satisfactory mixture for foundation piers is _one part_ Portland cement, _two parts_ clean sand, and _three parts_ gravel—two-inch aggregate is about right. It is a good idea to add to the mixture hydrated lime—about 10 per cent of the bulk of the cement—to prevent the mass from setting too rapidly and to make it work more smoothly.

This type of foundation allows perfect ventilation under the cabin, but it will not keep out wandering rabbits and other night prowlers.

A boulder foundation is quite enough for the average semi-permanent summer cabin unless you plan to spend time there during the winter, in which case an all-around foundation is advisable to keep out the cold.

Full concrete or rock foundations are more expensive and more work to build but hard to beat for permanence. To construct them, dig a trench to the dimensions of your cabin but at least twice as wide as your finished foundation wall is to be and to solid ground below the frost line. Pour in a “footing” of concrete to a depth of 10 inches. This base will distribute the weight of the cabin. (Fig. 5.) On this footing build wooden form walls to the proper height—about one foot above ground level at the highest point of your grade is usual—and fill them up with the proper mixture of concrete. To prevent dry rot of the wood construction, air vents should be constructed at intervals in the concrete wall above grade. These should be covered with screening to keep small animals out. Thickness of foundation walls varies according to the weight of the building. A good rule is to make the top of the foundation two inches wider than the logs or timbers it is to support.

BOLT FOR SILL LOG METAL TERMITE GUARD CROSS SECTION OF FOUNDATION WALL

The sill logs or timbers are laid on top of the foundation. If your cabin is to be of logs, select a number of the strongest and straightest and lay them so as to form the outside “frame” of the cabin. They should be bolted tightly to the concrete by means of long iron bolts previously buried in the foundation walls. If the sills are to rest on piers or boulders, spike them together. The weight of the cabin will hold the sills in place. The 2×6 floor joists are cut in or notched over the sills. They should be set with the 2-inch side uppermost and securely spiked.

The footing for the fireplace is made just like the concrete foundations—6 or 8 inches beyond the dimensions of the fireplace plus the hearth. Pour a slab of concrete about 10 inches deep, in which are buried ½ inch steel rods laid in both directions—checkerboard fashion—and wired at the intersections. This may seem like a lot of extra work but the steel rods prevent settling and cracking. On this slab build a wooden form to the height of the bottom of the floor joists and fill with a mixture of concrete, sand and plenty of small boulders. At this point block off the section to be used for the hearth and fill in the fireplace proper up to the floor level. This will leave a space to be filled in later with hearthstones, brick or whatever you decide to use for the hearth.

BUILDING THE CABIN FIREPLACE

If the chapters in this book were arranged in the order of their importance from the standpoint of cabin features, this one, dealing with fireplaces and chimneys, would probably come first. No matter what other ideas you may have about a vacation cabin you will undoubtedly insist on a fireplace as a dominant feature. To most people a cabin without one just isn’t a cabin at all.

When it comes to building it you can have the work done a lot easier than you can do it yourself. On the other hand, you’ll probably do a lot of arguing with the mason because, strange as it seems, there appear to be comparatively few masons who can build a fireplace and a chimney that will work to perfection. The instructions here have been collected from people who do know how, and if you follow them, you should have a successful fireplace.

In the preceding chapter you have read about the fireplace foundation. By the time the rest of the house is pretty well along this should be in good condition for the next step.

A fireplace consists of four essential parts: the fire box itself, the throat, the smoke chamber, and the flue. The shape and relationship of these are very important. One simple relation to remember is that the area of the fireplace opening should not be more than 10 times the area of the flue. Some people say 12 times, but 10 is a better average.

THROAT OPENING FULL WIDTH OF FIREPLACE CHIMNEY FLUE FLUE LINING SMOKE CHAMBER SMOKE SHELF DAMPER THROAT 8″ FIREPLACE

The over-all dimensions of the fireplace, including mantel, are matters of proportion and taste, governed by the size and shape of the room. In almost every case the width of the opening should exceed the height. The top of the opening should be at least 30 inches from the floor but not much more than 40 inches unless it is at least six feet wide—and not many cabins can stand a fireplace as big as that. For a six-foot opening plan for a depth of about 24 inches. No fireplace should have a depth of less than 18 inches. Remember, however, that the deeper your fire box the less efficient it will be for heating purposes. The hearth should extend at least a foot on either side of the opening and have a minimum depth of 20 inches.

You may have the opening flush with the hearth, or, as some builders prefer, lay a course of stone several inches high across the lower edge and curve the bottom of the fire chamber up to it. Or you may elevate the entire bottom of the fireplace. It is smart to plan the hearth flush with the floor so that trash may be swept into the fireplace without using a dustpan.

Rough native stone, of course, is the most interesting material for a cabin fireplace and chimney. Brick seems too refined for the woods. If you want the finished job to look as massive in appearance as possible, don’t use stones that are too small.

The walls of a stone fireplace and chimney should be at least one foot thick. But as a concession to safety, the entire fire box—back, sides and floor—should be lined with good quality firebrick. The space between the stone shell and firebrick lining is filled with concrete. Since the back and sides of the interior must reflect the heat into the room, the back must be slanted forward as it rises, running up straight about one-third of the height of the opening from the hearth floor and then slanting toward the front at an angle of from 23 to 30 degrees. The sides should slope inward, as they approach the back at, roughly, an angle of 60 degrees.

Regardless of whether the top of the fireplace opening is flat or arched, you will need a strong support at this point. The best is an iron bar about one-half inch thick and two inches wide. Extend it across the width of the opening and set it firmly in the stonework at each side. Any blacksmith can make this bar for you, and the curve he puts in it will determine the arch of the opening. A “T” bar, set with the tail of the “T” upward, is even better, since it is stronger and requires less iron.

Behind the bar build a wooden form extending back several inches and sloped slightly upward. Then lay a course of stone on top of the iron and fill in between the stone and the form with a rich mixture of concrete reinforced with iron rods. This concrete should rise at such an angle as to come flush with the edge of the damper. The reinforcing rods should extend the full width of the arch and tie into the stone at the sides.

Buy a Good Damper

Since the fireplace is probably the most important feature of your cabin, don’t skimp on materials. Buy the best dome-type damper that you can afford. Some fireplace “experts” will say this is nonsense, but don’t let them fool you. The damper is to a fireplace what a mainspring is to a watch.

The dome damper is set on top of the fire brick lining where the throat enters the smoke chamber. The handle to control it may be set in the front or side as you wish (make sure of this when you buy it) and may project or be set in a recess in the masonry.

The throat, as can be seen in Fig. 6, is considerably narrower from front to rear than the fire box—5½ inches is maximum—and should come as near the front as possible. It should begin 6 to 8 inches above the top of the fireplace opening, extend the entire width of the fire box and slant downward toward the back. At the same time the back surface of the fire box has been slanting forward until it reaches the same height at the beginning of the throat. At this point construct the smoke shelf, which is literally a shelf set back to the vertical line of your masonry.

DIRECTION OF PREVAILING WIND CHIMNEY CAP

Proper construction of the smoke chamber is often the factor that determines the success of your fireplace. The amount of taper may vary, but it is a good general rule to slope the walls inward one foot for every 18 inches of height. The smoke chamber walls must be as smooth as possible, the best finish being about ½ inch of mortar—or a commercial steel unit. This cuts down the amount of friction and makes it draw better. After the smoke chamber walls are tapered up to the desired dimensions, the flue is straight from here on up.

Use Special Mortar

Government specifications for fireplace mortar, which must be used in laying all work except the fire brick, are as follows: hydrated lime, nine pounds to each 94-lb. bag of Portland cement; mix this with three times its volume of clean sand and enough water to make a smooth workable mortar. Wet all stones before applying the mortar. _Don’t use ordinary_ lime mortar for fireplaces and chimneys.

Construction of the flue is the next important matter. The flue is installed as the chimney is built and must be planned with a fairly close relationship to the fireplace itself. Fireplace experts estimate that the correct ratio is 14 to 16 square inches of flue area to each square foot of fireplace opening.

A round flue is the most satisfactory type. It offers less friction and is easier to clean. Square or oblong flues should be slightly larger than if a round one is used. The easiest method—and one that assures a tight flue—is to use fire clay flue lining, filling in between it and the stone shell with cement. Be sure that the flue is as straight as possible and uniform in size right up to the top. Don’t taper it. If turns must be made in it, make them gradual—never greater than an angle of 45 degrees.

Don’t try to use one flue for fireplace and kitchen stove or another fireplace. Make separate flues for each. They may go up the same chimney but the two or more flues should be separated by at least four inches of solid brick or concrete unless tile flue linings are used. When you have reached the top, test the flue for leaks by lighting a fire and covering the top of the chimney. Escaping smoke will reveal any leaks, which must be repaired at once.

SMOKE DOME DAMPER DOWN DRAFT SHELF APRON—TO BE COVERED BY MASONRY WARM AIR OUTLET DAMPER CONTROL HEATING CHAMBER BOILER PLATE FIREBOX COLD AIR INTAKE

Location of your house will affect the action of the chimney, since large objects such as trees or a hill nearby will cause a down draught. If this trouble is encountered, it may be corrected by building an arch over the chimney cap. The arch should be placed at right angles to the cause of the down draught.

The chimney cap itself, which is an important feature affecting the air currents that pull the smoke out, should be about 12 inches high. It can be made of cement and stone chips, modeled by hand. Reinforcing rods or wire mesh may be added if desired. The sides of the cap should curve from the outside edge of the masonry proper to the top of the cap.

A good type of flashing, which must be installed to prevent leaks between the chimney and the roof, is made of sheet lead, which is everlasting. Galvanized iron or copper is also satisfactory. The flashing should be cut to fit the chimney like a collar and is imbedded in the masonry. The roofing should overlap the upper edge several inches, and the flashing must overlap the roofing at the lower edge if set on a slanting roof. In case the chimney comes at the ridge, flashings are fastened over the roofing all around.

While you’re up on the roof finishing the chimney, it would be a good idea to take the measurements of the entire top. In your leisure time, make a fairly tight cover, shaped like a shallow box, that will fit on top of the chimney when you close the cabin for the season. It can be lashed down with wire or rope. The object of this will be well known to anyone who has left a cabin chimney open for several months, because it seems to have a great attraction for birds and squirrels—not to mention the fact that snow and rain get in and rust the flue lining if it’s made of metal.

In planning your cabin fireplace don’t fail at least to investigate the several so-called “patented” fireplace forms which circulate heated air. (See illustrations.) These are especially worth considering if you expect to rely upon your fireplace for heating the cabin during the colder months, and also greatly simplify the intricate job of fashioning a fireplace.

When using these forms the fireplace is constructed with an air chamber behind the fire box. Cold air is drawn off the floor and circulated back in the room as warm air. This gives you both direct radiated heat and warm air from absorbed heat. Various installations are possible, with the added heat being used in an adjoining room—or even upstairs.

WARM AIR OUTLET COLD AIR INTAKE

BUILDING THE LOG CABIN

Mention of a “cabin in the woods” brings a vision to the average man of one thing—a _log_ cabin. And, although few people will ever build a real log cabin, most of us have inherited from our pioneer ancestors a romantic attachment to the sturdily constructed homes of our early settlers. The pioneers built of logs primarily because they had no other materials and also because they needed a shelter that would be a protection against Indians, wild animals and rough weather.

But just because a cabin is built of rough logs instead of finished lumber doesn’t mean that it will be less expensive in this day and age. According to such experts as C. D. Aldrich, who designs some of the finest cabins in the country, a log cabin costs about twice as much as a frame cottage of comparable size and design. A one-room-and-porch cabin that can be built of lumber for about $500 would cost roughly $1,000 if well built of logs.

There are two styles of log cabin construction—the traditional kind with the logs laid horizontally and the stockade type in which the logs or half logs are placed upright. The latter is easier to build since skilled axe work is not required to notch the log ends and the principal task is to hew down the sides to make them fit closely. On the other hand, a cabin built with horizontal logs is the favorite with most people—probably because it is the most familiar.

Logs for a stockade style cabin need not be particularly heavy since they are to be spiked to the horizontal members of a timber frame, but care should be taken to obtain pieces as straight as possible to avoid waste. Second growth timber is most frequently used. Chinks between the timbers are caulked with oakum, or, if the fit is very loose, combine oakum with willow wands or narrow battens. However, most people building a recreational home of logs will want the horizontal type of construction, so this chapter will be devoted to that subject.

One of the first things to decide after the rough plans are drawn and the list of materials estimated is whether the cabin is to be of peeled logs or logs with the bark left on. Logs that are to keep their bark must be cut in late October or November and stacked on skids until spring. Be sure they are piled so that plenty of air circulates. Logs to be peeled should also be cut in fall or winter and seasoned—preferably for six months or more. To prevent cracks when they begin to weather, have the logs scored down one side—a two or three inch strip of bark removed the entire length. Then if the logs crack a bit, they will do so along the scored lines and they can be laid so the cracks won’t show in the finished building.

The size of your cabin, or rather the dimensions of the various walls, is not necessarily limited by the length of the logs, because they can be spliced. (See Fig. 7 for the best method of splicing.) If you are counting on leaving a projection at each end beyond the wall, then you can figure that logs 20 feet long will give you a room with inside walls about 16 feet long. Logs between 20 and 30 feet long are most satisfactory unless you have a large crew to help. They should average about 10 inches at the top end with as little taper as possible. If you get smaller logs, it will require too many to gain the needed height, and logs much larger than that are unwieldy to handle.

The best timber for a log cabin on the Pacific Coast is redwood or western cedar. Balsam, hemlock, pine, and, if you are lucky, tamarack also make good logs. The latter are especially fine. You may buy your logs from a lumber company, from a public utility company’s supply of power-line poles, or you can hire a good woodsman to cut them for you—if you can find the timber. Certain sections of the National Forests are available for cutting logs and stumpage charge is very nominal.

There are several possible methods of fitting logs together. The choice depends entirely on how much time and labor you care to devote to it, but once a style has been adopted carry it throughout the whole house. Use similar logs or poles instead of dressed lumber wherever possible. They’re more “woodsy.” Speaking of style, all log ends that project should be finished off with an axe, not sawed.

After the sill logs are laid on the leveled boulder foundation, or in the case of a concrete or stone wall underpinning bolted to the foundation, the next step is to lay the floor joists. They should be not less than 2×6 material, spaced not over two feet on center. Notch them into the sill log and the first log above as shown in Fig. 8 and spike them in.

Use Spirit Level Frequently

You are now ready to start erection of the walls. Make frequent and careful use of the plumb line and spirit level in this work. Without constant checking the walls have a way of going off at odd tangents.

The simplest and least difficult style of fitting logs is the “saddle and notch,” in which the logs are given a rough notch and laid together without special fitting or trimming. The spaces are later caulked with oakum. While this is the simplest method, it is the poorest from the standpoint of weather tightness.

Another and better method is the same as above except that the notches are so carefully cut that the logs fit closely and must be hewn down along two sides to provide neatly joined surfaces. This also will require some caulking but not as much. It is customary to lay a strip of oakum between all logs, regardless of the style of fitting.

Cupped Logs Fit Snugly

A third method is to use “cupped” logs. The same saddle and notch is used at the corners, but the upper log has a concaved channel cut its entire length, which makes it fit down snugly over the lower log. The cup may be cut with curved-blade adz or with a heavy gouge. This is more work but well worth it. Cut each cup to fit its individual lower log, marking the cup with a pair of dividers to insure a close fit. When you have a perfect cup (which means rolling the log into position several times to try its fit) lay a layer of heavy oakum along the lower log, roll the upper into its final position and spike it down.

The finest method of all is a further refinement of the cupped log style. The upper log is cupped as above but, instead of a simple notch at the end, the upper log is cut out exactly to fit down over the lower tightly, while the lower is not notched at all. Oakum is strung the same as for other methods and laid in at the corners. In the best work of this type no oakum should show. Although the pioneers put their cabins together without nails, they did so because they had no nails to use. To be safe, spike all logs together with 12-inch spikes—the largest size made.

Before you get the walls too high, give a thought to windows and doors. There are two ways of taking care of them. The extravagant way, much used by our forefathers, was to build with logs to the top line of the proposed opening and then cut out a hole the required size. An easier—and less wasteful—way, if you are doing your own work, is to use short logs, leaving a more or less rectangular opening. Then nail a couple of straight boards where your frames should come and saw off the rough projecting log ends as illustrated above.

LOWER LOG HEWN OUT

Incidentally, in planning your house remember to take into consideration that a log cabin’s interior absorbs a great deal of the light unless—God forbid—you intend to whitewash the walls. Therefore, plan for as many windows as your walls will allow without unduly weakening them or disrupting your interior plans.

Use timber at least two inches thick for window and door frames and wide enough to protrude slightly on the outside of the log wall. The bottom piece—or sill—of the window frames should have a pitch of about one inch to the outside and project two inches to allow for drainage of rainwater. Don’t try to build your own windows. Order them to size from a mill and set them in.

Roof Should be Sturdy

The pitch of the roof and the width of the eaves are largely matters of personal taste and the kind of cabin you are building. A low pitched or flat roof, however, must be thoroughly braced if it is to bear a heavy load of snow, and the additional materials may cost more than a steeply pitched roof. The most effective roof for many cabins is low pitched with wide eaves—not too wide, of course, but wider than you’d have on a city house. Build the gable ends to the height you finally decide on; then trim down the rough ends along a line marked to the pitch of the roof.