Home improvement shows make it look easy, but installing insulation yourself can be messy, tiring and, if you don't plan carefully, as expensive as hiring a professional.

As you plan your insulation project, keep in mind that it's also important to use vapor barriers and ventilation to maintain a healthy balance of air and moisture movement throughout your home.

The number one rule is to follow the manufacturer's instructions exactly. Skipping steps and taking shortcuts could mean significant reductions in R-value - and a waste of your money and effort. Allow yourself plenty of time and make sure you have enough materials to complete the job.

You can do it yourself if:

  • You've identified the type and amount of insulation you currently have.
  • You can purchase the additional insulation from a reputable retailer with a knowledgeable staff.
  • You've successfully tackled other home improvement projects.
  • The area is accessible and easy to maneuver in, and has few obstructions.
  • No structural changes are involved.
  • The existing insulation is dry and properly installed.
  • Your roof is in good shape.
  • You're including vapor barriers and ventilation in your plans.

A few more tips to keep in mind

  • DO invest in "no-itch" products - they're much easier to handle and safer to work with.
  • DO wear goggles, a dust mask or respirator, gloves, long sleeves and long pants when working with insulation. For the best protection, wear a hat, tuck your sleeves into your gloves, and tuck your pant legs into your socks.
  • DO be very careful moving around in your attic. Watch out for overhead rafters, and walk only on ceiling joists. If you have room, lay a plywood panel across the ceiling joists to walk or kneel on.
  • DO install batts and blankets at right angles to the first layer.
  • DON'T disturb existing insulation - especially loose-fill. Moving it around can create gaps where air can leak through.
  • DON'T put insulation over recessed light fixtures, ceiling fans or ventilation fans. If you're using loose-fill insulation, use sheet metal to create barriers around the openings. Keep all insulation at least three inches away from chimneys and gas flue pipes.
  • DON'T cover attic vents, and leave at least one inch of air flow between the insulation and the roof.
  • DON'T forget to insulate and weatherstrip the attic opening.

Vapor barriers

During cold weather, water vapor from the warm inside air travels through unsealed holes and cracks, and condenses on cooler surfaces, including exterior walls, the underside of the roof and within insulation. This condensation can rot wood framing, blister paint, ruin insulation and damage the roof. Vapor barriers installed between insulation and interior surfaces can help prevent this problem.

You can purchase batt or blanket insulation with an attached vapor barrier, usually made of coated kraft paper or foil-backed paper. When using unfaced batts or blankets, or loose-fill or foam insulation, you can add four- or six-mil thick polyethylene sheeting.

If you're installing insulation yourself, remember these guidelines when using a vapor barrier:

  • DO place the vapor barrier towards the warm side of the insulated area - facing downward on the attic floor or to the interior side of the wall.
  • DO add a polyethylene vapor barrier on the floor of a crawlspace to reduce condensation from ground moisture.
  • DON'T add a second vapor barrier to additional layers of insulation - this can trap moisture inside the first layer. Use loose-fill or unfaced batts or blankets; if only faced batts are available, cut facing every few inches to allow air to pass through.

Learn more about vapor barriers and ventilation

Ventilation

It may seem like attic vents defeat the purpose of insulation, but they're a vital part of keeping fresh air circulating through your home. An unventilated attic can trap heat during the summer, raising the indoor temperature by several degrees and putting a strain on your air conditioner. During the winter, warmer air trapped in the attic can cause ice dams than can lead to serious roof damage.

Never cover attic vents with insulation. If your home has no attic vents, be sure to add several before installing new or additional insulation - your contractor or retailer can advise you on what's best for your situation.

For the best indoor air quality - and even greater energy savings - you can invest in a heat recovery ventilator. This device will provide continuous circulation to ensure your home has healthy air.

More from this category

Insulation options

Different types of insulation

The right insulation material for your home depends on where it will be used and what type you already have. 

learn more

Basements and crawlspaces

Unfinished basement

Insulating your new house's basement up to R-10 can help reduce energy costs by up to 12 percent.

learn more

Solar attic fan

Megan and Pete standing next to solar attic fan

Keep your attic properly vented with an attic fan. Learn about a solar operated option.

learn more

Spray foam insulation

Man touching spray foam insulation

Spray foam insulation does a great job of sealing up cracks and crevices, if it's installed properly. Learn more about open-cell spray foam options.

learn more

Vapor barriers & ventilation

Man inspecting vapor barriers

An energy-tight home requires adequate ventilation and vapor control to maintain healthy air.

learn more

Finding and sealing air leaks

Older home

Learn how to locate those pesky air leaks and what to do when you find them.

learn more

Weatherizing materials

Man caulking around window

A typical home will need about $50 in weatherizing materials - and the cost can be paid back in energy savings in just a few weeks.

learn more

Weatherizing tips & tricks

Caulk gun

Use this checklist to make sure you don't overlook hidden energy wasters in and around your home.

learn more