How To Understand The Layers Of Your Roof: Ventilation and Ridge Vent

How To Understand The Layers Of Your Roof: Ventilation and Ridge Vent

Michigan homes have a habit of revealing mysterious secrets, as with that stash of items recently found behind a closet wall in a house in Kent county. What can your roof reveal about itself? Go ahead, be curious about the layers of your home’s roof in the Grand Rapids area! 

Layers, But No Cake

Some homeowners mistakenly believe their home’s roof is one layer. Not true; like a delicious cake, your roof has layers (but avoid trying to nibble). 

You only see the top layer, the topmost roofing material (shingles, metal panels, tiles). Backing up that beautiful exterior layer are other parts, such as your ventilation system, including gable vents, powered vents, and ridge vents

Air It Out

For a Michigan home’s roof to function correctly, it needs to breathe. Not with lungs, of course, but with circulating air. Stale, hot air exits your attic space and is replaced by rising, cooler air. This constant circulation keeps your attic air at the same temperature and humidity levels as the outside air. That keeps all the major attic components from becoming too hot or damp:

  • Joists
  • Rafters
  • Sheathing
  • Insulation

Many minor parts also benefit from this regular exchange of air (pieces like struts, collar ties, purlin props, scissor beams — every piece of wood up there has a name). 

No Air?

Your home’s attic needs a constant, gentle flow of air coming in at the soffit vents (down at the eaves) and rising up to exit by the ridge vents, gable vents, or powered vents.

What if no air is flowing? Then expect mold and mildew, insect and pest invasions, damp or wet insulation, and dripping condensation. Often insulation gets packed too vigorously around the eaves, stifling the flow of rising air from the soffit vents. The soffit vents are visible on the exterior of your house; they are the horizontal grilles with holes too small for pests but ample enough for air to flow.

Sometimes the ventilation problem is at the other end, the ridge vents. If your Grand Rapids home’s roof is more than 20 years old, the ridge vents may be undersized or even absent. 

Ridge Vents

If you stand in your yard and look at your roof’s ridgeline (top horizontal), you should see a slight rise, like a long speed bump. That is your ridge vent; it is always capped in the same material as the rest of your roof.

The ridge vent itself is three parts:

  1. Slits cut through the sheathing to leave a wide gap at the very top of your roof
  2. Plastic mesh that allows airflow but prevents pest invasion
  3. Roofing material capping the plastic mesh, matching the rest of the roof

If you lack ridge vents, you must have either gable vents or powered vents to pull air out of your attic. If you have ridge vents but they are undersized, your attic and roof will suffer. 

Call It In

Annual roof inspections and minor roof repairs are sensible ways to keep your home’s roof healthy. Contact your neighborhood residential roofer for help. Ask for a roof inspection, and express your concerns about ventilation.

Your roofer will check:

  • The size and integrity of your roof vents
  • The airflow up from your soffit vents
  • The amount of insulation in your attic
  • The condition of the underside of the sheathing (where mold, mildew, and water damage are easily visible)
  • The amount of air flowing out gable or powered vents, if you have them

Your roofer can verify you have enough ventilation or can prepare a solution if you need more ventilation. Often, ridge vents can be cut in or modified to let passive ventilation perform its job. If your roof has a complex profile, you may need a combination of all three types:

  1. Ridge vents
  2. Gable vents
  3. Powered vents

Handle It Yourself?

What we have described may sound like a weekend do-it-yourself project. It is not. To begin, roofs are incredibly dangerous work surfaces, so never, ever climb on your roof.

Second, knowing the correct width of a newly cut ridge vent (into the sheathing) is professional knowledge. Too wide a slit, and the plastic mesh and roofing material cannot span the opening. Too narrow a slit, and you have inadequate ventilation.

Third, you risk voiding any roof warranty by performing amateur modifications or repairs. And fourth, you have access to highly trained, properly equipped roofers; why not let them handle the job and ensure proper attic and roof ventilation?

Moore and Sons Roofing provides a full range of roofing services for your home in the Grand Rapids area. Contact us today to see all we can bring to you, from roof inspections to complete roof replacement and more.

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