[Illustration: Fig. 2—Floor plan of the lean-to type of greenhouse shown in section on the opposite page.]
As our north wall is already in place, we have only four surfaces to consider, as the accompanying diagram shows—namely, south wall, gable ends, roof and openings. For the roof we will require a ridge against the wall of the dwelling house, sash-bars running at right angles to this, a "purlin," or support, midway of these, and a sill for the lower ends. For the south wall we will need posts, one row of glass, and boards and "sheathing." For the gable ends, a board and sheathing wall to the same height, and for the balance, sash-bars and glass. The required openings will be a door or doors, and three ventilators, to give a sufficient supply of fresh air.
[Illustration: Fig. 3—A sectional view of a two-bench, 10 X 20 ft. house built against the dwelling wall. If possible it would be well to gain a steeper slope for the glass and better headroom. The detail in the upper right hand corner shows, at larger scale, the plate and front lights, indicated just below in the main section.]
For these the material required will be:
10 ft. of 2-in. x 4-in. ridge $ 0.80 13 10-ft. drip bars 3.25 2 10-ft. end bars 1.00 5 6-ft. x 1-1/4-in. second-hand pipe posts .50 20 ft. 1-in, second-hand iron pipe 1.00 4 1-1/4-in. x 1-in. clamps .50 20 ft. 2-in. x 4-in. eaves plate 1.60 20 ft. 2-in. x 6-in. sill 2.20 15 1-in. pipe straps .50 18 ft. 2-in. x 4-in. sill, for gables 1.50 40 ft. side bars, random lengths, for gables 1.00 3 ventilating sash for 3 24-in. x 16-in. lights 3.00 9 16-in. headers for ventilators .40 6 hinges with screws for ventilators .75 1 roll tar paper, single-ply 2.00 6 boxes 24-in. x 16-in. glass, B double thick 24.00 75 lbs. good greenhouse putty 2.50 ——— Total of items listed above $46.50
All of the above will have to come from a greenhouse material supply company, and prices given do not include freight charges. The following items may probably be bought more economically in your immediate vicinity, and the prices will vary in different sections of the country:—
Total of items listed above $46.50 240 ft. rough 1-in. boards 7.50 6 posts, 4 in. thick, 6 ft. long, planed on one side} 3.00 2 posts. 4 in. thick, 8 ft. long, planed on one side} 1000 shingles 4.00 ——— Total cost of materials $61.00 Estimate of labor 20.00 ——— Total cost of greenhouse $81.00
Level off a place about 22 x 12 feet, and set in the posts as indicated in the plan on page 158, taking care to get the lines for the ends of the house perfectly square with the wall, and exact in length. This is best done by laying out your lines first with stout string, and making your measurements accurately on these. Then put in the posts for sides and ends, setting these about three feet into the ground, or, better still, in concrete. Put in the two corner posts, which should be square first. Next saw off all posts level at the proper height, and put in place the 2 x 4 in. eaves plate on top of these and the 2 x 6 in. sill just far enough below to take a 16 x 24 in. light of glass, with its upper edge snug in the groove in lower side of plate, as shown in detail of section on page 159. Fit the 2 x 6 in. sill about the posts so that the mortice on same will just clear the outside of posts. Then put on the siding on sides and ends—first a layer of rough inch-boards, running vertically, a layer, single or double, of tar paper, and a second layer of boards, laid horizontally, covering on the outside with shingles, clapboards or roofing paper. The five 7 ft. x 1-1/4 in. pipe posts may now be placed loose in their holes, and a walk dug out of sufficient depth to allow passage through the middle of the house. Rough boards nailed to stakes driven into the ground, will hold the earth sides of this in place.
Next, after having it sawed in two vertically (thus making 20 ft), screw the ridge securely to side of house at proper height, giving a thick coat of white lead at top to insure a tight joint with house. Now put one of the end bars in place, taking care to get it exactly at right angles with ridge, and then lay down the sash-bars, enough more than 16 in. apart to allow the glass to slip into place readily. Take a light of glass and try it between every fourth or fifth bar put into position, at both ridge and eave, as this is much easier than trying to remedy an error when half the glass is laid. Use "finishing" nails for securing the sash-bars, as they are easily split. Next, with chalk line mark the middle of the roof sash-bars, and secure to them the one-inch pipe purlin, which will then be ready to fasten to the uprights already in place. Next, make concrete by mixing two parts Portland cement, two of sand and four of gravel or crushed stone with sufficient water to make a mixture that will pour like thick mud, and put the iron pipe posts in their permanent positions, seeing that the purlin is level and the posts upright. (If necessary, the purlin can be weighted down until the concrete sets.) Then put into place the ventilators, glazed, and the headers for the same—short pieces of wood, cut to go in between the sash-bars,—and fit these up snugly against the lower edge of the ventilator sash.
When laying the glass in the roof, which will now be ready, use plenty of putty, worked sufficiently soft for the glass to be thoroughly bedded in it, and leaving no air-spaces or crevices for the rain to leak through later. If this work is carefully done, it will not be necessary to putty again on the outside of the glass, but it should be gone over with white lead and linseed oil. Be sure to place the convex surface of every light up. The panes should be lapped from 1/6 to 1/4 of an inch, and held securely in place with greenhouse glazing points, the double-pointed bent ones being generally used. The lights for the ends of the house may be "butted," that is, placed edge to edge, if you happen to strike good edges, but as a general thing, it will be more satisfactory to lap them a little. The woodwork, before being put together, should all receive a good priming coat of linseed oil in which a little ochre has been mixed, and a second coat after erection. I have suggested putting the glass in roof and sides before touching the benches, because this work can then be done under shelter in case bad weather is encountered. The benches can be arranged in any way that will be convenient, but should be about waist-high, and not over four or four and a half feet across, to insure easy handling of plants, watering, etc. Rough boards will do for their construction, and they should not be made so tight as to prevent the ready drainage of water. The doors may be bought, or made of boards covered with tar paper and shingles or roofing paper.