What Kind of Roof Do I Have? A Baltimore Guide
Fixing a roof the right way starts with knowing what's up there. A repair on a slate roof is a completely different job than a repair on a flat rowhome roof. Here's how to tell the common Baltimore roof types apart, mostly from the ground.
Asphalt shingles
This is what most sloped roofs in Baltimore County have, and plenty of city homes too.
- Looks like: flat rectangles layered like fish scales, usually gray, brown, or black, with a gritty, sandy surface
- Where you see it: suburban homes in Towson, Parkville, White Marsh, and Essex, plus some rowhomes with a pitched front
- Good to know: older roofs often have flat "three-tab" shingles. Newer ones are usually thicker "architectural" shingles with a more layered look. If you find a lot of grit in your gutters, the shingles are wearing.
Slate
Slate is real stone, split into thin pieces. It's common on older homes in Roland Park, Homeland, Guilford, and Bolton Hill.
- Looks like: thin, flat stone pieces with crisp edges, usually gray, green, or purple
- Good to know: slate can last a very long time, but individual pieces crack in freeze-thaw weather and the old nails rust out. A slate roof usually needs piece by piece repair, not a new roof. Don't walk on it. It breaks underfoot.
Flat and low-slope roofs
These are all over the city on rowhomes, and on porch roofs and additions everywhere. From the street you usually can't see them, so you may need to look from a back window or a neighbor's deck.
- Modified bitumen (torch-down): black or dark rolls with a rough, sometimes granular surface. The seams are often visible as overlapping strips. This is an asphalt-based material, not rubber.
- EPDM rubber: big smooth sheets of black or sometimes white rubber, no grit
- TPO: smooth, slick white or light gray sheets with welded seams
- Silver or coated roofs: a lot of older flat roofs have a silver or white coating painted on top of whatever's underneath
On any flat roof, the trouble spots are the seams, the drains or scuppers, and where the roof meets the parapet wall.
Metal and copper
- Looks like: long panels with raised seams, or metal shingles. Copper starts bright and turns brown, then green.
- Where you see it: porch roofs, bay windows, valleys, and flashing on older homes. Some houses have copper gutters too.
- Good to know: copper and metal usually fail at seams and fasteners, not across the whole panel.
Less common: wood shake and clay tile
- Wood shake: thick, uneven wood pieces that weather to gray. Rare around here, mostly on a few older homes.
- Clay tile: curved or flat baked tiles, usually reddish orange. You'll spot it on some historic homes in the city like in Mount Vernon. It's heavy and brittle, so repairs need care.
Why it matters for repairs
Each material has its own weak spots and its own repair methods. Patching slate with tar, or putting shingles on a roof that's too flat for them, causes more leaks than it fixes. Knowing what you have helps you ask the right questions when you call a roofer.
Our roof material guide goes deeper on each type, and our roof lifespan page covers how long each one tends to hold up in our weather. You can also see the roof repairs we do for each material.
Still not sure? Text a clear picture of your roof and your address to 443-900-4815 or give us a call, and we'll tell you what we're looking at. MHIC #154344.
