How to Build a Tiny House – Part 9:
Choosing and Installing Roofing Materials
From wooden shakes and metal roofing to asphalt shingles, there are numerous options for roofing materials to protect your tiny house. Choose your favorite and learn how to properly install.
By the Editors of Skills Institute Press
Good things do come in small packages. Just ask internationally recognized small living expert, Jay Shafer. Ranging in size from 100 to 120 square feet, Jay Shafer’s DIY Book of Backyard Sheds & Tiny Houses (Skills Institute Press LLC, 2013) features beautiful small houses can be used as guest cottages, art or writing studios, home offices, craft workshops, vacation retreats or a full-time residence. Whatever your building goal, this book will teach you how to plan and build your structure from the ground up. The following excerpts from chapter four, “How to Build a Tiny House,” walks you through selecting the best roofing type for your tiny house and the installation process.
You can purchase this book from the GRIT store: Jay Shafer’s DIY Book of Backyard Sheds & Tiny Houses.
Looking for other steps? Check them out in How to Build a Tiny House.
A Range of Coverings for Roofs and Sides
Selecting roofing and siding for an outdoor project depends on the design and intended use of the structure. Storage sheds are best sheathed in weatherproof materials, whereas lawn pavilions and shade houses can be left virtually open—although lattice can be added for privacy or shade. Hybrid designs, such as a waterproof roof with open sides or an open roof with solid sides, expand the range of choices.
Outdoor structures can be enclosed in much the same manner as houses. Rainproof options range from traditional shingle or clapboard to inexpensive, quick-to-install roll roofing. Each of these choices is applied over a base of plywood sheathing. A simpler alternative is corrugated plastic paneling. For an open roof, leave the rafters, with decorative end cuts, unprotected, or nail crosspieces between them. To provide more shade, you can cover the rafters with latticework or rows of slats, lattice, or shade cloth.
You can install these same materials, along with bamboo shades, as siding for an outdoor structure. Or, cover open walls with screening to let in light and air—and exclude insects.
Simple Waterproof Roofing
1. Setting Roll Roofing.
Nail 1/2-inch plywood sheathing to the rafters, driving 2 1/2-inch common nails at 6-inch intervals.
With 1 1/4-inch roofing nails, fasten the upper edge of a strip of roll roofing to the sheathing so that the lower edge projects beyond the eave by 1/2 inch. Fold the roofing up and spread a 12-inch-wide strip of roofing cement on the sheathing along the eave (right).
Press the strip firmly in place and nail its lower edge down.
Work your way up the roof, lapping each new strip over the one in place by 4 inches. On a gable roof, trim the last strips even with the ridge, cutting with a utility knife, then set ridge pieces (Step 2). On a shed roof, lap the last strip over the eave by 5 inches and fasten it to the crossbeam.
2. Covering the Ridge.
Cut pieces of roll roofing 12 by 36 inches and cement them along the ridge (left). Overlap the ends of the pieces by 6 inches. After pressing down each piece, nail it to the sheathing within 6 inches of the end. Then set the next piece, concealing the nailheads.
Airy Sheathing: Easy to Mount
Outdoor structures meant only for warm weather can be graced with a wide range of lightweight and inexpensive roofing and siding materials. Bamboo, woven reed, shade cloth, and corrugated plastic are suitable for structures like trellises and tree houses because they require minimal support and are attached quickly. Shade cloth is particularly suitable for sheltering shade-loving plants. It is available in a variety of weaves that admit different amounts of light. Woven reed and bamboo are normally employed to cover outdoor living spaces.
The easiest of these materials to install is shade cloth made of synthetic fiber; the polypropylene type is durable and lightweight. Shade cloth must be specially ordered through a nursery or garden shop, which will cut it to size, reinforce the sides, and install grommets to your specifications. Order the cloth so the finished size is 2 inches less all around than your roof (below). Ask for reinforced edges and No. 2 brass grommets.
Corrugated plastic panels are more difficult to install. Furring strips must first be nailed to the rafters and special filler strips attached at the top and bottom—but they do provide rain protection. They should be installed on a roof with a minimum pitch of 1 inch to 1 foot or, in a snowfall area, a pitch of at least 3 inches to 1 foot. Make sure that any wood you purchase to mount your sheathing is pressure-treated.
A Shade Cloth Cover
Lacing a Shade Cloth
Install 2-inch screw eyes at the corners of the roof, stretch the cloth across its opening, and tie the corner grommets to the screw eyes with good-quality nylon cord.
Position screw eyes around the perimeter of the roof, aligning them with the grommets in the cloth.
Tie one end of a length of cord to a corner screw eye and lace the other end through the grommet at the same corner. Continue feeding the cord through all the screw eyes and grommets on one side of the roof, tightening the cord just enough to remove the slack (above).
Lace the opposite side the same way, working with a helper to tighten the cord on both sides and keep the fabric centered on the roof. Tie the cord to the last corner screw eye.
Lace the remaining sides the same way.
1. Attaching Filler Strips.
Install a fascia board the same dimensions as the rafters to the lower ends of the rafters with 3 1/2-inch galvanized common nails. Fasten cross supports between the rafters at 3-foot intervals.
Nail scalloped wooden filler strips across the tops of the fascia board and cross supports with 2-inch nails (left). To ensure that the plastic panels fit properly, keep the filler strips aligned.
Cut half-round filler strips to fit on the rafters between the scalloped filler strips and fasten them in place.
Trim the panels to length with a circular saw equipped with an abrasive blade.
Working on a calm, windless day, position a panel on the roof so one end overlaps the fascia board and one edge overlaps an edge of the roof.
Drill holes 1/16 inch larger than 1 3/4-inch washered roofing nails through the panels’ crowns. Starting at the outside edge (above), drill through every second crown at 12- to 15-inch intervals. Cross supports and upper crossbeam. Do not drill the last crown on the inside edge. Nail the panel to the filler strips. If you are sheathing a gable roof, add a ridge piece to the peak before driving the top row of nails.
Position the next panel, overlapping the first one by one ridge. Align the bottom ends of the panels, and drill nail holes through both pieces at the same time. Lift the second panel, apply adhesive to the underside of the last ridge of the first panel, and drive the nails.
Install the remaining panels the same way.
Covering the Roof
Many cabins, like most houses, are roofed with asphalt shingles, but two somewhat less common materials may be more appropriate for your cabin or cottage: metal roofing and wooden shakes.
Metal roofing is economical and fire resistant, and for areas subject to heavy snowfalls, it provides a slippery surface that sheds snow before it can build up. Metal panels can be applied to a roof with a pitch of at least 3 inches of vertical rise for every 12 inches of horizontal run. The metal roofing shown here can be purchased in kits, which are available at most farm-equipment and building-supply dealers. The roofing comes in a variety of colors, with panels cut to specified lengths and with specially formed trim pieces or flashings to fit at the eaves, rakes, and ridge. Use a screw gun or drill to drive the appropriate fasteners at the intervals indicated by the manufacturer. The location of sealing strips and the correct overhang of the panels at rakes and eaves will also be indicated.
Shingles and Cedar Shakes
Available at home centers or lumberyards, asphalt shingles, wood shingles, and cedar shakes require at least a 4-in-12 slope. Shakes (below), though expensive, provide the most rustic covering. The methods illustrated on the following pages, simplified from those prescribed for year-round homes, are suitable for vacation and weekend cottages in moderate climates. A starter course of smooth-surfaced shingles is laid along the eaves, and the rest of the roof is covered with rough hand-split shakes.
Shakes are laid on an open deck of 1-by-4s spaced at an interval that is 1/2 inch less than one-half the length of the shakes.
1. Installing the Rake Panels.
Starting at the eaves, attach 30-pound roofing felt with 1 1/4-inch roofing nails, overlapping sheets by 6 inches. At the eaves, attach the eave drip edge included in the roofing kit with the fasteners provided (inset). Lay a sealing strip on the eave drip edge, parallel to the eave, then place the first metal panel with its end overhanging the eave so it is square to the eave and rake (left). Attach the panel by driving the fasteners supplied through the sealing strip and into the roof. Then fasten the panel along its length, staggering screws along each side at 1- to 2-foot intervals. Continue installing panels along the rake in the same way until you reach the ridge.
2. Covering the Rest of the Roof.
Lay a sealing strip parallel to the rake over the first rake panel, then place the rake drip edge over the strip and fasten it through the eave drip edge and sealing strip (above).
To install the other panels, place each one with its crimped edge overlapping the crimped edge on the adjacent panel, and with the overhang of the panels at the eaves equal to that of the first rake panel. Fasten the panels to the roof (above).
If you need more than a single panel length to extend from the eave to the ridge, overlap successive pieces by 3 to 6 feet, installing sealing strips at their ends.
At the opposite rake, cut the last panels with tin snips, if necessary. Install them, then add the sealing strip and rake drip edge along the rake.
Cover the other side of the roof in the same way.
3. Attaching the Ridge Cover.
On each side of the ridge, lay a sealing strip parallel to the ridge, then position a ridge cover over the ridge and attach it to the roof by driving the screws through the sealing strips (above).
An Asphalt-Shingle Roof
|Laying Courses of Shingles
Set up the scaffolds along the side walls. With a helper, snap chalk lines along the top chords of the trusses 4 and 8 feet from the overhang as guidelines for laying plywood sheathing.
Align the top edge of a 4-by-8 sheet of sheathing with the chalk line and center it over the fifth truss.
As a helper slips a plywood clip onto the top edge of the sheathing between each truss, secure the sheet with 2 1/2- inch galvanized common nails every 6 inches along the top chords (right).
After sheathing the bottom 4 feet of the roof, remove the braces fastened to the trusses and cover the next 4 feet, starting the row with a half-sheet in order to stagger the joints from the bottom row.
Before installing the last row of sheets, trim their top edges so the sheathing stops 1 inch short of the ridge. Cover the other side of the trusses the same way.
Lay the sixth course by nailing a halftab to the roof, then adding a full shingle. At the seventh course, repeat the pattern used for the first six courses. When you reach the rake, return to the eaves and add two-full size shingles to each course. Continue the process to cover the roof; trim the last course of shingles even with the ridge.
Finish the ridge with individual shingle tabs bent to cover both sides, starting with a tab at each end of the roof 1/4 inch beyond the rakes; working toward the middle, overlap succeeding tabs by 7 inches. Trim the top end of the last tab so at least 5 inches of the tab it covers is exposed. Bend a half tab in two and nail it over the two tabs that overlap at the middle of the ridge.
Laying Down Shakes
1. Laying a Double Starter Course.
For the first 3 feet up from the eave, install solid decking—1-by- 4s fastened edge to edge to the rafters with 2 1/2-inch common nails. Continue up to the ridge laying open decking. At the ridge butt the last two rows of decking boards together.
Cover the solid decking with 30-pound roofing felt, securing it with 1 1/4-inch roofing nails.
With 1 1/2-inch hot-dipped galvanized box nails, fasten a starter course of cedar shingles, overhanging the eave by 2 inches and the rakes by 1 1/2 inches.
Nail an 18-inch-wide strip of roofing felt over the shingles, 10 inches above the eave.
Driving 2-inch box nails with a shingler’s hatchet, lay the first course of shakes over the shingles, aligning the ends, but offsetting vertical joints by at least 1 1/2 inches (left).
2. Laying the Remaining Courses.
Cut a scrap shake to the length of the gap between decking boards—8 1/2 inches for 18-inch shakes; 11 1/2 inches for 24-inch shakes—and use it to align the bottom of each shake with that of the shake in the course below.
Lay an 18-inch strip of roofing felt with its lower edge halfway between the top of the starter course and the bottom of the next course.
Fasten the second course of shakes with two 2-inch box nails (right). Lay another strip of felt, then another course of shakes. Continue in this way to the ridge.
With 3-inch box nails, cover the ridge with special two-piece ridge shakes: Start by doubling the ridge shakes at one end, then overlap the shakes as you move along the ridge to the other end so the corner joints alternate from one side of the ridge to the other (inset).
For further instructions, see How to Build a Tiny House.
Reprinted with permission from Jay Schafer’s DIY Book of Backyard Sheds & Tiny Houses: Build Your Own Guest Cottage, Writing Studio, Home Office, Craft Workshop, or Personal Retreat by Jay Schafer and published by Skills Institute Press LLC and Four Lights Tiny House Company, 2013.Buy this book from our store: Jay Shafer’s DIY Book of Backyard Sheds & Tiny Houses.