Restoration Guide: Roof Tile
Editor's Note: This is article 12 of 13 in the Roofs Chapter of the Old House Web's Home Restoration Guide. This guide was developed and edited for old homes from original material in the U.S. Housing and Urban Development (HUD) Rehab Guide.
12. Clay, Concrete, Fiber-Cement & Composite Tile Basics
Tile is another longtime roofing material, now accounting for about 8 percent of the new-roof market, and 3 percent of the re-roof market. Tiles now are made of several different materials, including:
- Clay (traditional)
- Concrete (most prevalent material today)
Besides composition, tile is differentiated by other factors, including
- Profile shape (Pan and cover, S-tile, or interlocking)
- Flat shape (interlocking or non-interlocking)
- Absorption (porosity)
- Freeze/thaw resistance
- Installation details
Interlocking styles are preferred in heavy rain and snow areas because it they are a tighter system.
Porosity is a concern in climates with repetitive freeze-and-thaw cycles, because water absorbed by the tile will cause the tile to break down as it freezes (water expands as it freezes). Tile is graded by its resistance to frost, from Grade 1 (best) to Grade 3. Cement-fiber tiles have proven particularly troublesome in freeze-thaw climates.
Installation methods vary widely depending on the roof structure, the climate, seismic conditions, building codes and manufacturers recommendations. Nails are the least expensive and most widely used method; adhesives are becoming the preferred method in hurricane regions.
Methods and Materials
- Replacing Clay or Concrete Tiles
Clay and concrete-tile roofs present many of the same problems and solutions as slate roofs. Tile roofs have longevity, so if you have an old house with an original roof, it may well need close inspection.
A careful inspection from the ground or ladder will show problems such as:
- chipped or cracked tiles
- slipped tiles or missing mortar
- bad flashing and fasteners
You also want to inspect your old house's gutters and downspouts. Problems here could send water back under your roofing or onto your walls.
From inside the house, check the attic for water stains, rot or other moisture-related problems.
If you have limited damage, you probably can get by with spot repairs. If your old house's roof is less than 100 years old, you probably can find matching tile, either salvaged or new.
Tile repair generally is a job for a professional with specific experience--such repair is a little trickier than other types of roof repair. Walking on the tile will easily break it, and it can be very slippery.
Beware of an inexperienced roofer who may recommend replacing an entire roof when it still could be repaired. If there are problems such as flashing or underlayment--but the tiles still are sound--it is possible the tiles could be removed, repairs made, and the salvaged tiles re-installed. If some new tiles are required, they possibly can be placed in areas less visible.
Tile repairs can be difficult to estimate; the bill may grow as work progresses. Matching tiles may be difficult to find.
A badly damaged roof should be replaced; postponing a new roof could lead to extensive water damage and a major home renovation later.
- New Clay Roof Tile
If imitation is the highest form of flattery, then perhaps that red tone in the clay tile roof is caused by it blushing from all the praise. For decades, manufacturers have been producing roofing that attempts to mimic clay tile.
Much like slate roofs, clay tile roofs last seemingly forever, and because of that, you must make sure that your underlayment also is of the highest quality. And while the red-tile roof is traditional, clay tiles also come in a variety of earth tones and glazed primary colors, which hold their color over time.
Clay tiles are virtually maintenance free, fireproof and impervious to insects and decay. They also withstand high wind better than other roof material. They are resistant to freeze-thaw cycles.
Because they are so heavy, the roof's supporting structure may have to be reinforced. The roof should be at least a 4" on 12" pitch. Clay tiles are very expensive, which is countered by their longevity--another roof is one home renovation you won't have for several decades. There are limited manufacturers in the United States, so shipping can increase the cost dramatically.
- New Concrete Roof Tile
Concrete roof tiles come in a variety of shapes and colors, often mimicking clay tiles, shake and slate. As with clay, the longevity of concrete means you need to use high-performance underlayment that will last as long as the tile; in California and the Southwest, the tiles may last fifty to sixty years, while in the Southeast, they may last twenty to thirty years.
Concrete tiles are more difficult to install than many other materials, and like clay, the roof should pitch at least 4" on 12". They also are heavy, and an existing roof structure may need reinforcement.
- New Fiber-Cement Roof Tiles
Fiber-cement shingles are composed of Portland cement, synthetic or natural wood fibers, and sometimes a lightweight aggregate. They are made to simulate slate and wood shakes.
They are lighter than clay and concrete tiles, and some may be installed over existing asphalt shingles. They don't rot, split or curl, and can be made to look very realistically like wood and slate. Like the previous two materials, they require at least a 4" on 12" pitch.
They are more porous than concrete and clay tiles, thus are more susceptible to damage from freezing and thawing. They will break under foot traffic.
- New Composite Shingles
Composite roof shingles are fairly new on the market. One product by Owens Corning is made of slate and clay reinforced with fiberglass and bonded with polymeric resin.
They are lightweight, don't fade and don't absorb water. They install like wood shakes.
Because this is a new product, it does not have an accurate performance history.
- New Plastic Composite Roof Tiles
Another fairly recent product, plastic composite tiles are made from a variety of materials, including recycled pallets, plastic bottles, plastic bags, etc. They are lightweight and easy to install with conventional fasteners. They perform well in wind and hail. The recycled content makes them environmentally friendly.
They have only a Class C fire rating, and have not had the test of time to prove durability.
Jim Mallery, a semi-retired journalist and onetime registered contractor, has extensive experience remodeling, repairing, and rebuilding homes.