How to Inspect Your Attic

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Attics are a vital component to your home as it provides structural support as well as protecting your house from water damage. Improper insulation, venting, and electrical wiring can compromise the integrity of your attic and pose a serious risk to the v

For most homeowners or home buyers, attics are often the last thing you think about but there are many reasons to make sure that your attic is in good order. The attic can provide information on the condition of the house that other inaccessible components cannot. Structural issues may be present due to alterations, water damage from failed flashing or roofing materials, mold growth, pests, ventilation problems, and the occasional electrical repair gone awry. If left unchecked , minor problems in the attic can develop into more serious issues that can affect the value or your home and the safety of your family.

Trusses and Rafters

The roofing system of most modern homes are constructed from prefabricated wood trusses. These components are designed and manufactured to provide a stable structural system much like the traditional rafter system. Trusses utilize smaller framing members to support the load of the roof. Trusses also speed the construction of a roof, especially where there are complicated roof pitches.

There are three common problems with roof trusses; damage during construction, improper bracing, and removal of support members. During construction, trusses are delivered by truck to the construction site and either installed immediately or more often they are unloaded from the truck and installed later. Depending on how they are unloaded from the truck and how they are stored, damage can result. Occasionally trusses are improperly braced when they are installed, or the bracing is removed after the plywood roof sheathing is installed.

Finally, truss member may be cut away or altered to allow for ductwork or plumbing vents. It is beyond the capability of most homeowners to determine if a truss system is structurally sound, so if you notice any alterations or damage to trusses in your attic or cracks in your ceiling or walls, call a home inspector or structural engineer to investigate.

Correct storage of trusses

Incorrect storage of trusses

Loose gusset plate and split vertical web.(Note the mud on the truss)

Roof trusses can be repaired using plywood gussets, but the repairs must be done according to the manufacturer’s recommendations.

For rafters, you should visually inspect them to see that they are not severely warped or split.  Also check for damage from termites, carpenter ants, or rot. Roof rafters should be braced properly with collar ties, underpurlins, struts, beams, or a combination of these. You should not remove any of these components to create more headroom or storage space.

Diagonal bracing is usually required on gable end walls to counteract wind loads.

Cracked roof rafter

Sheathing should not be sagging or damaged. Newer homes have metal clips to span the gap between the sheets of plywood called H-clips. This strengthens the roof system to prevent damage from heavy snow loads and when the roof is walked on.

Insulation and Venting

Attics can be insulated using loose-fill insulation or batt insulation. The R-value of the insulation required is based on your climate. You can find recommendations for attic insulation at Energy Star home insulation table

Look for areas where the insulation has been removed, damage from pests or roof leaks, and check to make sure that there is a vapor barrier in place.  Problem areas are typically above showers in bathrooms and near the eaves where insulation could be too far from the edge or pushed into the eave and block vents.

Take a look outside at the point where the roof meets the wall as not every home has eave or soffit vents. If there are vents installed, make sure that there are rafter baffles to allow air to enter the eave and flow up to the ridge or gable vents. If you have a ridge vent you will notice a metal strip along the peak of your roof or an elevated course or shingles that is covering a plastic ridge vent. If you have a ridge vent, make sure that the plywood is cut away about 2 to 3 inches from the ridge to allow for air to flow through. Ridge vents are typically installed when a home has the roofing replaced.

From the ground the ridge vent will look like a shadow along the peak of the roof.

Properly installed ridge vent with sheathing cut away.

Inadequate opening for ridge vent.

Another issue with ventilation of attics is that bathroom exhaust or dryer vents are sometimes left open to vent into the attic instead of being run to the outside of the attic. This can create a serious fire risk for dryer vents and a moisture and odor problem for bathroom vents.

Bathroom vent terminated inside attic.

The last thing to look for with attic insulation and ventilation are penetrations in the ceiling or through stud cavities. Plumbing and electrical penetrations should be sealed to prevent conditioned air from passing through the attic.

Roof Leaks and Water Damage

Look for staining on the roof sheathing and around any roof penetrations and support walls which can indicate a current or previous leak. Condensation can form around pipes or ductwork which can cause wood to rot. Condensation can also form on the underside of the roof sheathing in the winter if moisture is present in the attic.


Chimneys can be constructed outside the house, or pass through the attic. That portion of the chimney that is not exposed to the elements can weather and deteriorate, especially the older the chimney is. Look for cracks in the bricks and whether the mortar has crumbled. Also check for water stains where the masonry penetrates the roof. If you notice any black stains or scorch marks you should have your chimney inspected by a professional. Soot or hot gases could be escaping from the flue and can pose a fire or carbon monoxide risk.

Pests Damage

Squirrels, mice, or bats are commonly found in attics. Look for damaged insulation, fecal matter, urine stains, and chewed wood or electrical wiring.  Bees or wasps can also build nests in the attic which can be a dangerous situation for you and your family. Serious damage can occur to the home if left unchecked so if any animals are present, hire a pest control professional to remove the pests before repairing damage to the attic.

Electrical Issues

Most people do not consider electricity when they think about attics, but most bedrooms have a ceiling light fixture present, as well as bathroom lights and exhaust fans. Many times when these are installed or replaced, junction boxes are left open or improper electrical splices are made. Inspect any area where ceiling fixtures are present and look for junction boxes with missing covers and loose ceiling boxes.

Improper wiring in the attic. All electrical splices should be made inside a junction box.

Ductwork and Plumbing

As a general rule the only plumbing inside an attic should be vent stacks. These will come up through the wall cavity and continue on through the roof sheathing. Make sure that the vents are not hanging loosely or disconnected. In most cases, two or more vents should not be combined into one. Plumbing supply lines should not be run through attic spaces due to the potential for freezing, even if the pipes are insulated. In extremely warm climates plumbing supply lines are run through attics.

A more common problem is open ductwork or flex duct that is twisted, damaged, or compressed by electrical wires.

Open ductwork wastes energy an can cause condensation problems in the heating and cooling seasons. When air handlers are installed in attics, make sure that there is a drip pan in place beneath the unit to catch any condensation coming off the unit, ductwork, or from the condensate drain line. Pay close attention to attic air handling units as they are often forgotten about when it comes time for routine service and filter changes. Proper service is important especially if there are used for heating as well as cooling.

Excessive flexible ductwork results in poor indoor air quality and comfort levels


Eva Blake-Knox
Posted on Jul 25, 2016
Sandy James
Posted on Apr 5, 2012
John Smither
Posted on Apr 5, 2012