What Should You Look For in Your Attic?

The attic is the most informative place in the house and the least visited. It is the one location where you can get close to the underside of the roof safely, and what you find there tells you more about the condition of the roof than the covering does from outside.

It is also where several expensive problems announce themselves early. Moisture, poor ventilation, failed insulation and small leaks all show in the attic long before they show on a ceiling.

If the insulation looks thin, the Attic Insulation Calculator shows how much you need to reach the recommended R-value for your climate.

When to go up

Timing changes what you can learn, so it is worth going up more than once a year.

A cold morning in winter is the single most useful visit. Condensation and ventilation problems are visible then and invisible in July. Go up during or just after heavy rain if you are chasing a suspected leak, because a wet track is far easier to follow than a dried stain. And a hot summer afternoon tells you whether the space is venting, because an attic that is dramatically hotter than outdoors is not.

The underside of the roof deck

Start with a flashlight pointed at the boards above you, working slowly across the whole area rather than looking at one spot.

Daylight through the deck means a hole, and it is the one finding that needs acting on immediately. Dark staining or a bloom on the timber means the deck has been wet, though not necessarily that it is wet now. A single dark track running down a rafter is the signature of a leak, and following it uphill leads to the entry point rather than to the drip.

Frost or beads of water on the underside on a cold morning is condensation rather than a leak, and it is a different problem with a different fix. So is glittering frost on the points of the nails coming through. Rusting nail points tell you the same story over a longer period.

Sagging between rafters, or a deck that is visibly bowed, is a structural finding and belongs with a professional rather than on a list of things to monitor.

The insulation

Insulation tells you about heat loss, and heat loss is behind a surprising number of roof problems.

Look at whether it is even, and whether it reaches all the way to the exterior walls. It very often stops short, leaving the coldest strip of ceiling uncovered, and that gap is where ice dams tend to form in cold climates.

Look for compression. Insulation squashed under boarding, storage boxes or a walkway has lost most of its value. Look for damp, matted or discoloured patches, which mark either a leak above or a moisture problem below. Wet insulation does not recover its performance even after it dries.

Then look for the things that should not be there: insulation packed against a recessed light fixture, which is a fire risk, or blown insulation pushed into the eaves and blocking the airflow path.

Ventilation, which is usually the finding

Air should enter low at the soffits and leave high at the ridge. Both halves have to work.

From inside, look towards the eaves and see whether you can make out the soffit vents, or whether they are buried under insulation. Blocked intake is extremely common and it disables the whole system, because a ridge vent with nothing to draw from does very little. Baffles are the inexpensive fix that keeps the channel open.

Check where bathroom fans and dryer ducts terminate. A duct that stops in the attic, or vents into a soffit where the air is drawn straight back in, is pumping warm wet air into the coldest part of the house. It is one of the most common causes of a damp attic and has nothing to do with the roof. There is more on the whole system in why a roof needs ventilation.

Other things worth noting

• Droppings, nesting material, chewed timber or chewed cable insulation, which means something has moved in.
• A musty smell, which means moisture has been present long enough for growth.
• Daylight around a chimney, a vent pipe or the hatch itself.
• Water stains around penetrations rather than in open areas, which points at flashing.
• An uninsulated or unsealed attic hatch, which is a large hole in your ceiling.
• Ductwork that is uninsulated or leaking at the joints.

What to do with what you find

Photograph everything, with the date. Attic problems are slow, and the useful comparison is between this winter and last winter rather than between what you see and what you expected.

Sort findings into three groups. Daylight through the deck, active dripping, structural sagging and chewed wiring need somebody now. General frost, blocked soffits, insulation that stops short and ducts venting into the space are jobs to plan for warm weather. Everything else is a note to check again next time.

Take the photographs with you when you get quotes. A contractor who is shown a picture of frost on the sheathing has a very different conversation with you than one who is shown a stain on a ceiling, and it makes it much harder to be sold work you do not need.

Conclusion

Twenty minutes in the attic on a cold morning is the cheapest and most revealing roof inspection a homeowner can carry out, and it requires nothing but a flashlight and care about where you put your feet.

Look at the deck, the insulation and the ventilation path, in that order, and photograph what you see. Most of what you find will be nothing. The value is in the year you find something while it is still small, and in never having to take a stranger’s word for what is above your ceiling.