Synthetic Slate and Composite Shake Roofs

What synthetic slate and shake are made of

Most synthetic slate and shake tiles are injection-molded from polymers. Premium products use engineered virgin resins with UV inhibitors, impact modifiers and fire retardants blended through the material, so a scratch reveals the same color underneath. Others rely on recycled rubber, plastics or mineral fillers. Recycled content can be a selling point, but it can also mean more variation from batch to batch.

Tiles come in single widths, mixed widths and several thicknesses. Mixed-width blends laid in a planned random pattern look most like hand-laid slate. DaVinci Roofscapes, which makes polymer slate and shake, is the synthetic brand we install; the comparison points on this page apply to any manufacturer you are considering.

Weight: synthetic slate roofing versus natural slate

Natural slate commonly weighs somewhere between about 800 and 1,500 pounds per roofing square (100 square feet), depending on thickness. On a house framed for asphalt, that load usually calls for an engineer’s review and sometimes added rafters or sheathing. Polymer slate weighs a fraction of that, closer to heavy asphalt shingles, so most homes take it without reinforcement.

The lighter weight changes the repair story as well. Natural slate cracks when walked on carelessly and needs a specialist with slate hooks and copper nails. Synthetic tiles tolerate careful foot traffic and are fastened with the roofing nails the manufacturer specifies, which makes adding a vent or replacing a damaged piece a routine job.

Synthetic slate impact and fire ratings: check the exact product

Synthetic roofing marketing leans on ratings, and for the leading products the ratings are genuine: many polymer slates are tested to UL 2218 Class 4 for impact and carry a Class A fire rating. The catch is in the fine print. A Class A rating may apply only when tiles go over a specified fire-resistant underlayment, and an impact rating belongs to a particular product and thickness, not to a whole brand.

Ask for the listing information for the exact tile on your quote. If a possible insurance credit is part of your reasoning, ask your agent whether that specific product qualifies before you order, since carriers set their own rules.

Installing composite roofing through Chicago seasons

Polymer tiles move with temperature. Manufacturers specify side gaps between tiles so summer expansion doesn’t push them into buckles, and those gaps have to suit the conditions on installation day. In cold weather the material stiffens, so crews cut more carefully and follow any minimum installation temperature the manufacturer sets. Each fastener goes exactly where the instructions say, snug but not crushing the tile.

Flashing is the other half of the job. A roof meant to last decades deserves flashing to match: heavier-gauge prefinished metal or copper in the valleys, step flashing and counterflashing at walls and chimneys, and a full ice barrier at the eaves. Cheap flashing under an expensive roof undermines the whole investment.

Synthetic slate roofing compared with designer asphalt and metal

For a slate or shake look below the price of natural stone, there are three realistic paths. Designer asphalt shingles cost the least and look convincing from the street, but have a shorter service life. Stone-coated or profiled metal roofing lasts about as long as synthetic slate and sheds snow, but looks more manufactured up close. Synthetic slate sits in the same upper price tier as metal, has the most authentic profile of the three, and offers strong impact performance. Steep, visible roofs on homes the owners plan to keep are where it earns its cost.

How it handles Chicago-area weather

Care and maintenance

Polymer tiles need little routine care. Clear leaves from valleys and from behind chimneys, keep gutters running, and look over the flashings every few years, since the metal around the tiles often wears out before the tiles do. If a branch gouges a tile or one cracks, a roofer can slip a replacement into the course, which keeps repairs small. Ask the installer to leave a small stock of each color in your blend; matching a specific production run years later is the hardest part of any repair.

Synthetic Slate and Composite Shake: common questions

Does synthetic slate fade over time?

Some color shift is normal in the first years outdoors. Better products are formulated with UV stabilizers to keep that change gradual and even. Ask to see an older installation of the same color rather than relying on a new sample board.

Can synthetic slate go on a low-pitch roof?

Each product lists a minimum slope, often with extra underlayment required near that minimum. Check the figure for the exact tile before planning a porch roof or a low rear addition.

Is synthetic slate a good replacement for a failing natural slate roof?

Often, when the slate is truly at the end of its life and a new natural-slate roof is out of reach. Have the roof assessed first; sound stone with failed flashing or nails can sometimes be repaired rather than replaced.