Attic Insulation: 10-Minute Fixes and the Basics - Sutton — Canadian Real Estate Listings & Agents |

Attic Insulation: 10-Minute Fixes and the Basics

07 October 2019

Without adequate insulation in an attic, frigid winter air radiates downwards, seeping through the ceiling, the walls, and openings such as hatch doors, power outlets and lighting fixtures. Expensive heated indoor air is lost, driving up heating bills. In the summer, the situation is reversed with hot, attic air adding to the costs of air conditioning.

10-minute Fixes

Seal power outlets

  • Start by sealing the gaps around your power outlets, especially those located on exterior-facing walls. At the circuit breaker, turn off the electricity. Next, unscrew the plastic cover on the outlet. Use caulking to fill gaps between the drywall and the outlet’s electrical box.
  • Another trick is to use a foam gasket against the underside of the cover. As you tighten the screws back into the wall, the gasket squeezes into gaps helping to block the drafts.
  • Even with these measures, you may notice cold air coming through the prong openings of an outlet. An easy fix for this is to insert inexpensive childproof covers into any unused power outlets.

Seal an attic hatchway

  • Hatchways in the ceiling are another entry point for cold air. An easy way to seal an attic hatch door is to use foam board insulation and weather-stripping. For this project, choose 3” thick foam board. Measure or remove the hatch door to use it as a template for cutting foam board to exactly match the size of the door. Double-sided tape simplifies the process of attaching the foam to the back of door. Next, use weather-stripping with an adhesive backing to seal all four edges inside the hatchway. Replace the door with the foam board facing toward the inside of the attic.


The Basics

Insulation compresses over time, so eventually homeowners will need to replace their attic insulation. Before tackling the project or hiring a professional, it is helpful to know the basics.

What is R-value?

R-value refers to resistance to heat flow. It is a standardized measure of insulating capacity with higher numbers indicating greater insulating capacity. All new product should be labelled with their R-value.

Spray foam or fibreglass batting?

Professionals typically install spray polyurethane foam since it requires specialized equipment and can be hazardous when wet. According to the Houzz team of experts, spray foam is a heat-activated polymer that is made by mixing two ingredients onsite. The mixture is sprayed through a heated hose. As a chemical reaction between the two ingredients takes place and the substance heats up in the hose, the liquid turns foamy, expands then eventually hardens in place.

There are two types of spray foam: Open-cell spray polyurethane foam that is lightweight but has a low R-value. Closed-cell spray foam is more expensive, but offers some benefits: it can provide more rigid support, it acts as a water vapor barrier and is more dense and less permeable than open-cell products giving it a greater R-value.

Fibreglass batting is usually available in thicknesses between 15-45 cm (6-18 inches) and can be installed by knowledgeable homeowners or by professionals.

Pink, fiberglass batting usually comes with a vapour barrier on one side. That vapour barrier should be placed next to the warm side (e.g., touching the floor of the attic). Warm air holds more moisture and as it comes in contact with cold air, the moisture condenses. If the condensation gathers in the batting, it reduces the product’s insulating properties. Mold and mildew may develop.

How much is enough? Pink fibreglass insulation at 15 cm (6 inches) thick is insufficient for attic insulation. This Old House recommends that homeowners add a second layer of insulation placed across (perpendicular to) the first layer to block any cold air that may seep between the tiny spaces around the edge of the first layer of insulation. Be sure to remove the vapour barrier from the second layer to avoid condensation.

The best laid plans

Even the best insulation will be inadequate, if there are gaps in the attic floor and walls. Cold and heat will continue to flow through those gaps reducing the effectiveness of the entire system. Begin by filling the gaps. Professionals will even lift up floorboards to fill gaps where wall joists meet the attic floor. For small jobs, use canned spray foam or a tube of caulking.

Attics can be dark, dusty, cobweb-strewn places, but bravely venturing inside to make upgrades will provide decades of increased comfort and energy efficiency.

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