How to Insulate a Cathedral Ceiling

If you're looking to cut down on energy waste and make your home more efficient, a great place to start is by learning how to insulate a cathedral ceiling. In this guide, we’ll explore the unique aspects of insulating cathedral ceilings and highlight the most efficient systems and foam insulation.

Materials for Insulating Cathedral Ceilings

Choosing the right insulation materials is key to keeping your cathedral ceiling energy efficient. Here are some of the best alternatives available:

Radiant Barrier (Reflective Insulation)

For insulation of cathedral ceilings, using radians or reflective insulations is the best option. For example, our SmartSHIELD Reflective Insulation provides a reflective layer that protects radiant heat thus keeping the home cool during summer and warm in winter.

Radiant barriers work by reflecting up to 97% of the radiant heat that strikes them, reducing heat transfer through the ceiling. This makes radiant barriers especially effective in hot climates, where it can significantly reduce the heat gain from the sun. For optimal insulation, it's recommended to use radiant barriers in combination with other materials to create a complete insulation solution.

Spray Foam Insulation

This insulation is the top choice for cathedral ceilings nowadays. You've got two options: open-cell or closed-cell cellulose. Most people these days are going with this kind of insulation for their high ceilings. You've got a couple options though - there's open-cell and closed-cell cellulose foam. Both can get the job done, it just depends on your specific needs and preferences.

Rigid Foam Insulation Boards

Boards made of rigid foam insulation such as polyisocyanurate or extruded polystyrene (XPS) have very high R-value as well as a high ability to resist moisture. They can fill in the voids between the rafter and are mostly used together with basking extrusions and other forms of insulation for completeness.

Fiberglass Batts

Fiberglass batts are relatively cheap and convenient to install to the cathedral ceilings. They are provided in standard pre-cut sizes which easily fit most frameworks, and many may be put on top of one another to reach the required r-value. The average R-value of fiberglass batts lies between R-2.9 to R-3.8 for every inch of batts, largely dependent on the product.

Maintaining the shape of insulation batts while installing them in places is equally important as their functionality. This means that the batts are cut to the correct size and taped in such a way that they are installed cumulated in between rafters, and vapor barrier is placed on the warm side of insulation so that moisture damage can be avoided.

Cellulose

This insulation is mainly made from recycled paper and has extra fire resistance from its additives. It can be blown into cathedral ceiling spaces, no matter the shape, for good coverage. Cellulose is an environmentally friendly product while still maintaining considerable R-value, usually within the range of R-3.2 to R-3.8 per inch.

Although settling improves on the R-value, it negatively influences the R-value on the top of the cavity by causing an imbalance which sometimes requires refinishing.

Materials for Insulating Cathedral Ceilings

How to Insulate a Cathedral Ceiling Step-by-Step

Now that you know the best materials for insulating your cathedral ceiling, let's walk through the step by step of how to insulate a cathedral ceiling:

Step 1: Take Accurate Measurements

If you practically measure an area between the rafters before buying any insulation, it would help you find the right fit.

Don't waste energy by putting insulation where it's not needed. Consider all factors before installing. Wires, and water pipes, ducts need to be considered as well while taking those measurements.

Step 2: Position the Insulation Correctly

Gently fill up the spaces between the rafters with the insulation material, but do not use too much material as this will make it all squashed up.

A staple gun or adhesive will be used to attach the insulation, but keep in mind the instructions supplied by the manufacturer.

Step 3: Install the Pieces Between the Rafters

Install the insulation principle between the rafters, but handle carefully, keeping it rather snug, without pushing it into the material.

Attach integral insulation using a staple gun or adhesive, or whichever method is required by the manufacturer’s manual. For batts and rigid foam boards, always cut them as precisely as possible to any utilities present in the cavity to avoid constricting the batts or foam board.

Step 4: Insulate Around Light Fixtures

When insulating around recessed lights that give off heat and most other heat-generating fixtures, use mineral wool or other similarly rated fire-resistant insulation. Follow the light fixture manufacturer’s guidelines or keep effective clearances as per the recommendation of a thumb rule.

Step 5: Seal Any Gaps in the Insulation

After completing the insulation installation, apply appropriate foam sealant or caulking material to the edges and any open spaces in the wall. This will help prevent air movement and increase the efficiency of the insulation.

As a viable insulation alternative, check out our Do It Yourself Insulation Kits or DIY Reflective Insulation Sheets. These products are easy to install, making it simple for you to achieve excellent results on your own.

How to Insulate a Cathedral Ceiling Step-by-Step

Save Energy, Save Money with Insulation MarketPlace

Insulating your cathedral ceiling is a smart investment as it will enhance energy savings, comfort and reduce carbon emissions. Using the right materials and methods can not only make your home warmer and more comfortable but also reduces your power bills for years to come, while also saving energy.

Check out our store to explore all the great options we have for you. You’ll find everything you need to start transforming your home into a cozy, energy-efficient space. It’s all about making your home more comfortable while saving on those energy bills!