A LEAN-TO type of roof has been chosen for this building because of the ease of construction, and also because this style allows of a more pleasant frontage. Again, the building is shown made up in four units or sections, plus a separate roof assembly. This involves the use of a little more quartering for the framework, but simplifies the work of construction. Moreover, the building is then portable and can be removed from one site to another.
The frontage is 12ft. Overall; the ends measure 8ft.; the height at front is 8ft. 3in., and at back it is 6ft. Oin. The roof, with its purlins and framework, adds a little to the total height, and the floor beneath the building raises the latter about 4 in. from the ground level. Note that while the front and back units are the full width stated, the units for the two ends are narrower than the 8ft. Overall width quoted above, since these units fit be-tween the front and back frameworks, and therefore the thickness of the framework and its matchboard covering must be deducted in order to get the net width of the end-unit frameworks. There are windows in both ends, and another at the back. Further, the two openings in the front of the building, to left and right of the doorway, may be closed in by removable glazed sashes in windy weather; or one opening may be closed and the other left empty. Such sashes would be held by stops nailed down to the top and bottom of the opening, and secured by iron buttons screwed to the face of the window frame. A half-glazed door is also optional. For convenience in summer weather, the hinges should be lift-off butts, and then the entire door could be taken off the hinges and removed. The handyman is strongly advised to contrive, somewhere inside the building, racks where the window sashes and door could stand out of harm’s way when thus taken down.
A wooden floor composed of inch board nailed down on to joists 3 in. x 2 in. is prepared on the site, after the ground has been levelled. The joists run from front to back of the building, so that the boards run the long way. First dig out any loose soil, clear away any vegetable matter, and lay down about four inches of hardcore, clinker, or similar hard material all over the site, rolling it firm. Level this with a long straight-edge and a spirit-level. Nine joists will be needed; the boards should project all round about four inches beyond the outside of the shelter; this means that the joists should be about 8ft. Oin. Long, and the boarding about 12ft. 5 in. long.
Sound deal, 3 in. x 2 in. in section, is used for most of the framing, but the outside posts of the front and back units may well be of 3 in. x 3in. Section. If it is desired to Lessen the cost, the outside posts of the end units may be of 3 in. x 2 in. timber, and the bottom and middle horizontal pieces also, but the rest in these two units may be of 2 in. x 2 in. quartering.
Use mortise-and-tenon joints for the principal members, making the tenons a tight fit and driving the frame together with blows of a mallet, or by hammer with a piece of waste wood interposed between hammer and framework. The posts rest on the sills (the horizontal lower members), tenons going into mortises in the sills. The top horizontal members are mortised to fit on to stub tenons formed on the top of the posts. When a framed unit is completed, raise it and allow it to lean against a wall in its natural position (‘top’ at the top, etc.) until ready for erection. Meanwhile apply two good coats of creosote or gas-tar, as a preservative.
Figs, 1 to 3 show matchboarding nailed vertically to the frames; it should not be thinner than Jjin. Actual (which means ½ in. nominal) thickness. The cladding for the front unit can be left until the shelter frame has been erected in position. As for the three remaining units, let us take the left-hand end unit as an example of procedure. First note that the roofing sheets are fastened to purlins cut from 2 in. x 2 in. deal; these purlins run lengthwise of the roof, and rest upon the top members of the unit frames. It follows that the boarding, if it is to cover the depth of the purlins, must be approximately 2 in. longer than the height of the end unit, and be cut away at certain places to allow the ends of the purlins to come through. Begin nailing on matching at the left-hand side, allowing for the width of the post of the back frame, which has also to be covered by the first width of matching. Cut a length of board to the proper slant at the top (this can be marked with an adjustable bevel, setting the latter by the top and side of the end frame). Push the board up until it projects zin. Above the sloping top members of the end frame, and mark where it comes to the foot of this unit at the bottom; cut it off½ in. shorter.
Tack on this first piece with nails that do not go far into the studding, so that it can be taken off later. Fit and tack the next piece in the same way, also the third length, which has to be cut around the window opening at the top. These three lengths are not to be permanently fixed at present. Proceed now with the remaining boards, which come below the window opening; but do not attach the short pieces on top of this opening for the time being.
The number of boards will depend on the width of matching available and chosen; if a narrower board has to be used to make up the width, fit it in somewhere at the middle of the unit. The groove or tongue of the commencing board would have to be planed off, of course, and similarly the edge of the final board. Proceeding along this unit, we come to the last three boards, which should be fitted and tacked only. The remaining end unit is to be dealt with precisely in the same manner. The back unit also should have the first three and last three boards loosely attached for the present.
Assembling and Erecting
The three boards temporarily tacked are to be taken down before moving the units on to the platform, but first clearly mark these boards for their proper place. Three temporary struts made of quartering (2 in. x 2 in. will do) will be needed here; a helper should be ready to give a hand. Lift the back unit on to the floor and stand it in the proper position. In order to keep this position during the rest of the assembly, nail down two pieces of stout board at the back of the back unit, on the floor, close against the side of the woodwork. While the helper steadies the unit, nail one piece of strut to the top rail, the strut coming down slantwise in front and resting on the floor; drive a couple of spikes into the foot of the strut and through into the floor. Put another strut at the back of the unit, if there is room for it. With the aid of the assistant, lift the left-hand unit on to the floor and edge it into proper position. Secure it with a strut from top to the floor.
Get three hexagon head bolts ready, size ¾ in. x 6in., with nuts and washers. Also have at hand a strong G-cramp big enough to span the two adjacent posts of the end unit and back unit. Put on the cramp at about the middle of the height. Test the end unit for level, and use thin wedges under the sill if needed to bring it horizontal. The first hole is to be bored a few inches below the middle horizontal rail. Fix a 1 in. centre-bit in a brace and standing at the back of the back unit, bore into the post about I’m. With this bit; replace the bit now with a -gin. Twist-bit. Complete the hole, right through both posts, with the smaller bit; withdraw it gently so as not to displace the units.
Next, insert the bolt from the back, and tap it gently through so that its tail projects from the left-hand post of the end unit. In order to get the nut screwed up tight, it may be necessary to interpose a thin plate of wood, about -£in. thick, between the nut and the face of the post. (For we actually need bolts only about 5in. Long, but this is not a stock size). Have such a piece of wood, about 2 in. square, all ready. Put on the wood plate, which forms a sort of washer; then slip on the steel washer, and screw on the nut. Finally, put an ordinary-spanner on the nut and twist it up tightly. Here the bolt itself may turn round, so the handyman will now need a tubular spanner to put in the recess made by the large centre-bit and grip the spanner head. Let the helper see to this end, while the handyman now uses the long spanner on the nut.
Next, use a stool or an old chair to reach the topmost bolt-hole, and repeat the operation here. The third bolt, near the floor, must now go in in the same way. Final tightening may wait until later, but the bolts must be firm enough to hold the units steady. Nail a piece of board at the outside of the end unit, as was done with the back one, to keep these units from shifting along the floor. Let the struts stay in place while the right-hand unit is erected, bored and bolted. Then lay a piece of quartering, or a length of 1 in. board, across the roof-space about 9in. From the front, and temporarily spike it down so that the distance between the two side units at the front is exactly the same as at the back, where the back unit settles this dimension.
Now the front unit is to be offered up to the rest of the building, and discrepancy corrected, by gentle taps with a hammer to one or other end frame, and a pair of G-cramps put on for the time. Bore for bolts at the left-hand end, taking the middle hole first and putting in that bolt. Move over to the right-hand side next, and insert a similar bolt (middle one) here. The rest of the assembly is easy. The strut to the back may have to be taken off before the front unit can be got in place.
Securing the Units of the Floor
By taking off three first and last boards of the back and end units we incidentally exposed part of the sill of those frames. This space will probably be wide enough to allow a brace and bit to be used to bore a hole through sill and floor, to take a bolt which will fix the sill to the flooring. Two such bolts in each sill are needed. Another method is to bore a hole through the sill, and take it a little way into the flooring (where one of the joists comes in a suitable place) with a bit of smaller diameter. Then we can use a coach-screw instead of a bolt, and take it down into the joist as well as into the floor. Unless the building is fixed in some such way, it may move on the floor in high winds. Bolts are more satisfactory where they are able to be used.
Four purlins will be needed—one over the front top rail, one over the back top rail, and two more equi-distant between these outer ones. Fix and mark the positions on the sloping top rails, for the two middle purlins. Plane off the top edges of the two outer purlins (which rest on the front and back frames) until the slope is in line with that of the tops of the two middle purlins. All the purlins can be spiked down on to the tops of the units, or, where the top frame-member is accessible, a bolt can be put through instead.
Corrugated asbestos-cement sheeting is recommended for the roofing, though corrugated steel can be used instead. We may point out here that asbestos-cement can be sawn with a hacksaw, or a wood saw with not too coarse a tooth. Holes must be drilled with a twist drill, and screws should be used to fix the sheets to the purlins. No hammering must be done. Holes are made in the tops of the corrugations, not in the hollows, and a sufficient overlap must be given to the side seams. Sheets 9ft. Long will be suitable for the job, and as they are 2ft. 6in. Wide, we shall need six in all, allowing for overlap and side projections. There are specially designed screws and washers for corrugated roofing. Do not buy the ‘drive-screws’ also sold for such work, since they have to be knocked in with a hammer. Ordinary galvanized screws are available for the job.
At the eaves a piece of inch board can be screwed on lengthwise to make a neat finish to the end units. A similar length of board, about 2 ½ in. to 3in. Deep, should be fixed to the top of the front unit, close under the roof, as a fascia. Window sills, cut from 1 in. or 1 ½ in. board, can be fitted to all window openings; a bcvelled-ofT piece of 3in. X 2 in. deal or oak will make a threshold for the door opening, nailed down at the front and level with the top of the bottom frame member here. The spaces for the purlins can be cut away in the matchboard, and this board finally fixed; the first three and last three are already ‘off,’ so we can deal with them at the bench. Fix these boards with galvanized screws; they cover the bolts, and if we ever take down the shelter we shall need to remove the boards to give access to the bolts. The short boards on top of the window opening in the end units have not yet been fixed, so we can easily cut them where needed for the purlin ends. They can be nailed on permanently.
Suggestions for Windows
Probably enough ventilation can be afforded by making one sash in the back window to open, with the usual stay and latch. If this plan is adopted, divide the back window space into three vertically, and make two of the divisions ‘fixed’ sashes. The windows in the end units will normally be fixed glazing also. There is a simple way of glazing these, by adopting vertical glazing bars such as are used in greenhouse work. A glance at any glasshouse will give the handyman the details needed. Simple sashes on a similar plan can be made for the front of the sun parlour. A door (half-glass) is better bought than made, and probably a suitable one can occasionally be picked up second-hand.
The framing of the front unit would then have to be settled after obtaining the door. A transom can be inserted at the top of the doorway to suit, or the top panelled in with matchboard to fit the height of the door. There is much to be said, having gone to the trouble of building a substantial shelter, for making it an all-weather resort by these little extra details.
The entire inside of the building may be lined with sheets of building board screwed to the framework, which will give a better appearance and added comfort. The roof also can be finished off inside in this way.
When erecting the sun parlour, choose a day that is not windy. Go through the operations with your assistant beforehand, and make sure all the tools and appliances are conveniently near.