Poorly insulated or ventilated attic (entretoit): what it is, how serious, what it costs

The attic is the space between the top-floor ceiling and the roof. You usually get in through a small hatch in a hallway or closet ceiling. It holds three things: the insulation, which keeps the heat in the house; the ventilation, which moves outside air under the roof; and the framing that carries the roof.

In a French report, it is called « entretoit », and sometimes « comble », « grenier » or « vide sous toit »: it is the same space.

It depends on what the inspector saw there. Insulation thinner than what is installed today is a matter of comfort and heating bills: I put it under “Can wait”. Frost, water stains, mould, compressed insulation or signs of rodents go under “To check”: the cause has to be found. A broken framing member or water coming through the roof goes under “Fix first”.

The attic is also often viewed only from the hatch. If your report says so, whatever was not seen remains an unknown.

Adding blown-in insulation: $900 to $2,000 for one section, $2,300 to $5,000 for the whole attic. Adding roof vents: $500 to $1,400. Insulating and weatherstripping the hatch: $200 to $500.

When there are signs of moisture or mould, a targeted evaluation comes first: $400 to $900.

These are ballpark figures for Quebec, to be confirmed with quotes.

1. Could you see the whole attic, or only from the hatch?
2. Was there frost, water stains, mould or darkened wood under the roof?
3. Are the soffit air intakes clear, or blocked by insulation?

Ask the seller whether there have been large icicles along the roof edge, or water stains on the top-floor ceiling.

Does your report mention the attic? Upload it: in five minutes, I tell you what comes first, what to have checked and what to ask the seller.

Much more than was installed in the 1970s or 1980s. The inspector often compares the depth measured with the value recommended today. An older house is not at fault for that: it is an upgrade to plan.

Because the heat should stay below the insulation, not in the attic. Cold air coming in at the soffits and leaving near the top of the roof keeps the underside of the roof cold and dry. That prevents condensation in winter and ice dams along the roof edge.