A slate look without the weight: synthetic slate roofing in Vancouver, WA

Synthetic slate is a roofing tile molded from polymers, rubber and other composites, shaped and colored to look like split stone. It is installed one piece at a time like real slate, with staggered joints and a deep shadow line, but it weighs far less and can be cut and nailed with roofing tools. For most homes here, that means a slate look without reinforcing the rafters.

We install synthetic slate on steeper roofs where the surface is visible from the street, often on custom homes, older houses being restored and homes where an HOA wants a high-end look. It is a different job from composite shingle roofing: each tile is placed by hand, valleys and hips take more detailing, and the deck and underlayment have to be in better shape because the roof is meant to last a long time.

How synthetic slate compares with real slate and shingles

Natural slate is heavy enough that many wood-framed homes need structural work before it can go on, and broken pieces are hard to match later. Synthetic slate weighs closer to a heavy architectural shingle, so the framing question rarely comes up. Individual tiles are also flexible enough to take a footstep or a falling fir cone without cracking, which matters on a roof that will need gutter and moss work over the years.

Compared with architectural shingles, synthetic slate costs a lot more and takes longer to install, and fewer crews do it regularly. What you get is a thicker, more dimensional surface with a stone look, wide color blends and tiles that do not shed granules into the gutters. Lifespan claims and manufacturer warranty terms vary by product, so we go over the specific product's terms with you before you choose.

What goes into a synthetic slate install

The tile itself is only part of the roof. Because each piece is nailed through a narrow area near its top, the deck has to be flat and solid, and the underlayment carries more of the waterproofing load in valleys and at walls. We plan the layout before the first tile goes on so courses stay straight across dormers and the hip and ridge pieces line up.

• Tear-off and full deck inspection
• Replacement of soft or uneven decking
• Ice and water membrane at eaves, valleys and walls
• Synthetic underlayment across the field
• Copper or painted metal valleys and step flashing
• Matching hip and ridge pieces with a vented ridge

Moss, wind and upkeep on composite slate

Synthetic slate is not immune to moss. On a shaded north slope under firs, moss will still find the joints between tiles, especially at the bottom edges where water lingers. The surface is smoother than a granulated shingle, so moss tends to take hold more slowly and brushes off more easily. Zinc or copper strips near the ridge help, and gentle cleaning is safer than pressure washing, which can scuff the tile surface.

Wind performance depends on fastening. Each tile is nailed in a set pattern, and for high-wind areas makers often call for extra nails or a different nail line. We follow the product's high-wind instructions on homes that face the Gorge winds. Hip and ridge pieces get the same care, because the ridge is where east wind usually starts peeling a roof apart.

Is synthetic slate right for your house

It suits steep roofs with lots of visible surface, homes with a historic or custom look, and owners who plan to stay long enough to get value from a higher upfront cost. It is a poor fit on low-slope roofs, which most slate products do not allow, and on a house you plan to sell soon, where the price gap over architectural shingles may not come back at sale.