Insulation Types at a Glance: Batts, Loose Fill, Foam, and More

Materials overview

Why there are so many types to begin with

If one product did everything well, there would be no need for a guide like this. In reality, a roof space, a block wall, a garage ceiling, and a crawl space all place different demands on a material. One needs to cover an irregular surface, another has to resist moisture, another must fit between tight framing, and another has to be easy to remove later. Different types exist because different jobs exist.

Materials also differ in how they slow heat. Some trap tiny pockets of still air in a fibrous structure. Some hold gas inside closed bubbles. Some reflect radiant energy instead of resisting conduction. Understanding which mechanism a product relies on helps you see why it is placed where it is, and why combining types is sometimes sensible.

This page gives you a simple map, not a verdict. It does not tell you which type is right for your home, because that depends on the assembly, the access, the moisture conditions, and your goals. It does give you the vocabulary to follow an installer's explanation and to ask sharper questions.

A word on names: you will hear brand and trade names in conversations about insulation, but the categories on this page matter more than the labels. A product name tells you who made it. A category tells you how it works and where it tends to fit. When someone uses an unfamiliar name, simply ask which category it belongs to and what it is meant to do in your home. That one question clears up most confusion.

Batts and rolls: the familiar blankets

Batts and rolls are pre cut blankets, usually made of fiberglass or mineral wool, sized to sit between studs, joists, or rafters. They are probably the form most people picture when they hear the word insulation. They come with or without a paper or foil facing, and they are placed by hand in open cavities.

Their strengths are simplicity and fit in open, regular framing. Their weakness is sensitivity to installation. A batt that is squeezed, folded, or left with gaps around wiring and pipes loses a large share of its benefit, and a batt that gets wet tends to dry slowly. They also do not seal air by themselves, so leaks around them remain unless addressed separately.

In South Florida, batts are often found in older attics and in frame walls. They can be a sound choice in the right setting, but they ask for careful workmanship. If you are weighing them against other options, the comparison of batts and blown in material goes deeper.

Batts also come in different widths for different framing spacing, and the facing matters. A facing can act as a vapor control layer, and where it sits relative to the humid side of the assembly is something an installer should be able to explain for your house. In a hot humid climate, the placement logic can differ from what is common in cold regions, so do not assume a rule of thumb from another part of the country applies here.

Loose fill: blown in material

Loose fill is made of small fibers or granules that are blown into place with a machine. Common materials include fiberglass and cellulose. Because the material is blown, it flows around obstacles, filling irregular spaces and covering the tops of joists in a way that blankets struggle to match.

That flexibility makes loose fill popular for attic floors, where the open space is wide and the shape is uneven. It can also be dense packed into closed wall cavities in some situations. Installers aim for even depth and coverage, keep material clear of vents and recessed fixtures where needed, and use baffles to protect airflow at the eaves.

Loose fill can settle a little over time and can be disturbed by pests or by foot traffic, and like other fibrous types it does not like to stay wet. It also does not seal air by itself, so many plans pair it with air sealing. Read more about this approach on the blown in insulation service page.

Different loose fill materials have different personalities. Fiberglass fill is light, does not absorb much water in its fibers, and is common in attics. Cellulose is made from recycled paper treated for resistance to fire and pests, is denser, and can hold some moisture. Each has a place, and the choice often comes down to the assembly, the moisture picture, and what the installer is comfortable standing behind for your space.

Spray foam: open cell and closed cell

Spray foam is a liquid mixture that expands as it is applied and hardens into a foam. It sticks to the surface, fills small gaps, and can double as an air seal. There are two main families. Open cell foam has a soft, sponge like structure that lets vapor pass and is lighter. Closed cell foam has tightly packed cells filled with gas, is firmer, and resists water and vapor much more.

Because it adheres and seals, foam is used where air movement is a concern or where the surface is awkward, such as under a roof deck or in the cavity of a block wall. It can also add some rigidity. Some homeowners choose it for sealed attic assemblies, where the roof deck itself is insulated rather than the attic floor.

Foam brings its own questions: the odor during and after installation, how it is handled around wiring, and whether it can be removed in the future. The guide to open cell and closed cell foam explains these differences carefully, and the spray foam service page describes how the work is approached.

Because foam bonds to what it touches, it deserves extra planning. Roof decks, rafters, and wiring all become part of the assembly, and future repairs may be harder in a foamed area. That is not a reason to avoid foam. It is a reason to ask where it will go, what will be accessible afterward, and how a leak in the roof above would be found and fixed.

Reflective products and radiant barriers

Reflective insulation looks quite different from the others. It is typically a thin foil or metalized layer, sometimes bonded to a sheet or board, installed to face an air space. Instead of trapping air in a thick layer, it reflects radiant heat away. That matters most in a hot attic where the roof deck radiates downward.

Reflective products work only when they face an open air space, because their value comes from reflection rather than thickness. Dust buildup and poor placement can reduce their effect. They are not a replacement for resistive insulation, and the two are often discussed together, with a radiant barrier addressing roof heat and a thicker layer addressing conduction.

In a sunny climate this category gets a lot of attention, and also a lot of confusion. The guide on radiant barrier myths and facts helps separate what these products do from what they are sometimes said to do.

One practical note is that the reflective surface should face the air space it is meant to work with, and that the installer should keep it clear of wiring and respect the attic ventilation paths. Foil is conductive, so work around electrical components belongs to trained people. For a homeowner, the useful question is simply where the barrier will be placed and how that placement fits the attic as a whole.

Rigid board

Rigid board comes in sheets of foam plastic or fibrous material with a firm, flat face. It is cut to fit and fastened or adhered to a surface. Because it is continuous, it can reduce thermal bridging across framing members, and some types provide a degree of moisture resistance.

Typical uses include the inside face of block walls, garage walls and doors, roof and foundation applications, and spots where a thin but effective layer is needed. It can be combined with other materials, for example board over a wall followed by a finish.

Rigid board does not fill irregular spaces on its own, so seams and edges need attention to prevent air movement, and it must be protected as required by local rules, which you can ask your city building department about. It is an option you may hear about when thickness is limited or when a wall needs a continuous layer.

Different boards have different faces and different behavior around moisture and heat. Some are faced with foil, some are plain, and some are made of mineral fiber rather than plastic foam. The facing, the joint treatment, and the way the board is fastened all influence the outcome. Ask which board is proposed, why it suits the wall, and how the seams will be handled so that air does not wander behind it.

How these types behave in heat and humidity

Heat and humidity are the two conditions that matter most in South Florida. Fibrous products slow heat well when dry and properly installed, but they can lose performance if they absorb water. Foams generally resist moisture better, with closed cell the strongest in that respect and open cell more permeable. Reflective products care mostly about radiant heat, not moisture, though condensation near them can still be a concern in some assemblies.

Humidity also affects how a material dries. A wall or attic that can release moisture slowly tends to be forgiving, while an assembly that traps moisture can cause trouble regardless of the product. That is why installers ask about leaks and ventilation before recommending a material.

If you remember one thing, make it this: no material is waterproof magic, and no material is doomed in a humid climate. Everything depends on the match between product, assembly, and conditions. You can read more in humidity and insulation in Florida.

Matching types to places in the house

Attic floors commonly use loose fill or batts, with radiant barriers added on the underside of the roof deck in some homes. Sealed attic designs use foam on the roofline. Walls in frame homes may hold batts or dense packed fill, while block walls may use rigid board, furring with batts, or foam. Garages often call for foam or board because of moisture exposure and irregular framing. Crawl spaces, where present, bring their own moisture considerations.

Condos and townhomes add further wrinkles. Shared walls, shared ceilings, and association rules can limit options and shape what makes sense. Noise control may call for dense materials or special assemblies, which the soundproofing page explains.

Because every house mixes these zones, many homes end up with more than one type of insulation. That is normal. The goal is to choose well for each space, rather than to find a single product for the whole building.

Transitions between types deserve a moment of thought, though not a worry. Where attic fill meets a foamed section, or where a wall board meets a ceiling, an installer should leave no obvious gap in the thermal and air barrier. You can ask to see those junctions when the work is walked through with you, because they are where small oversights tend to hide.

Questions to ask about any type

Whatever type is proposed, a few questions apply. How does this material behave if it gets wet? How will gaps, corners, and penetrations be handled? What will keep it from blocking vents or being compressed? How does it work with air sealing? And if it ever needs to be removed, what would that involve?

It is also fair to ask why this type was chosen over the others for your particular space. A strong answer refers to your assembly, your access, and your goals. A weak one repeats general claims about the product. You are looking for reasoning, not slogans.

Finally, ask how the finished work will be reviewed with you. The process is meant to end with a walk through of the completed area, so you can see what was done and ask about anything unclear. Our guides library has more pages on these questions.

Where to go next

If you are choosing between two specific options, the compare section sets them side by side. If you are curious about the full range of work, the services overview describes each type of installation. And if you already have a symptom in mind, such as a room that stays hot, start from the problems pages and follow the links back here for the material background.

When you are ready to talk it through, call and describe your home: the property type, the area, and the rooms or spaces that concern you. From there conditions are looked over and a direction is chosen that matches the material and installation approach to the assembly and the goal.

Insulation types are tools, and good tools are chosen for the job. With the basics in hand, you can listen to an installer's recommendation with confidence and decide whether it fits the house you actually have.

It can help to keep a small notebook while you learn. Write down the type each person recommends, the space it is meant for, and the reason they gave. After two or three conversations, patterns appear. You will notice which recommendations are tied to the building and which sound like habit, and you will know which questions to repeat. That record also becomes a handy reference if you plan work in stages over several years.

Questions and answers