The breather membrane will help reduce heat loss from wind wash where air movement over the insulation draws heat out of it , reduce draughts from uncontrolled ventilation and allow any water vapour within the structure or insulation to escape, but more about that later.
But there are, in my opinion, a lot of downsides with this form of insulation. Not lease the Volatile Organic Compounds VOCs that they give off, the fact that they do not readily absorb or release water vapour and the fact that they are chemical based, to name a few.
Traditionally, in a new build cavity wall, there would be a layer of insulation board against the inner leaf of the wall and an air void next to the outer leaf of the wall. But if there are gaps between the sheets of insulation the thermal efficiency for the wall falls off a cliff. The principle of this was to have a gap next to the outer leaf in order to avoid any moisture that may penetrate the outer leaf from being transported across the insulation to the inner leaf which could cause penetrating damp within the home.
In an existing property with cavity walls you can't obviously remove the outer leaf to install insulation boards and maintain a gap. So the only options are to pump in insulation or insulate externally or internally. But the latter two usually aren't done due to the increased costs involved. Filling an existing cavity with insulation can raise its own issues which are explained in my article on cavity wall insulation problems below. There are of course a few types of cavity fill insulation that are available but I'm not a fan of many of these for reasons I'll go into within the articles below.
If your existing property has solid walls then your only option is to insulate internally or externally. You have a huge choice of materials but you should use a material that is breathable and install a vapour barrier or VCL and an airtightness layer if you want to do it right. Have a read through the articles below to see what the advantages and disadvantages of each are and why the majority of these types are installed incorrectly, without vapour barriers, VCLs and airtightness layers.
If your home has suspended timber floors on the ground floor theres a good chance that they're pretty draughty and uninsulated.
Some people add rolls of fibreglass wool between the floor joists held in place with chicken wire but this isn't ideal and thermally isn't great.
The good news it that once you've decided to do it the extra stages involved in insulating your suspended timber floor right aren't that difficult and will make a massive difference to how the floor insulation performs.
When upgrading the insulation in your loft area it will depend on whether you have an open loft or a room in roof type loft. Both can be done but the latter will be more difficult unless you're about to carry out refurbishment works anyway. Have a read through each of the articles above and you should be able to see which of my choices for the 'best insulation for homes' is going to be right for your situation.
Provided your chosen option is installed correctly the best insulation for your home will be the one you go for after getting all the relevant information and making your own informed decision based on your unique circumstances. Insulating an Old or Existing House. Concrete block walls are typically insulated or built with insulating concrete blocks during new home construction or major renovations. Block walls in existing homes can be insulated from the inside.
Go to insulation materials for more information about the products commonly used to insulate concrete block. Foam boards -- rigid panels of insulation -- can be used to insulate almost any part of your home, from the roof down to the foundation. They are very effective in exterior wall sheathing, interior sheathing for basement walls, and special applications such as attic hatches. They provide good thermal resistance up to 2 times greater than most other insulating materials of the same thickness , and reduce heat conduction through structural elements, like wood and steel studs.
The most common types of materials used in making foam board include polystyrene, polyisocyanurate polyiso , and polyurethane. Insulating concrete forms ICFs are basically forms for poured concrete walls, which remain as part of the wall assembly.
This system creates walls with a high thermal resistance, typically about R Even though ICF homes are constructed using concrete, they look like traditional stick-built homes. ICF systems consist of interconnected foam boards or interlocking, hollow-core foam insulation blocks. Foam boards are fastened together using plastic ties.
Along with the foam boards, steel rods rebar can be added for reinforcement before the concrete is poured. When using foam blocks, steel rods are often used inside the hollow cores to strengthen the walls.
The foam webbing around the concrete-filled cores of blocks can provide easy access for insects and groundwater. To help prevent these problems, some manufacturers make insecticide-treated foam blocks and promote methods for waterproofing them. Loose-fill insulation consists of small particles of fiber, foam, or other materials. These small particles form an insulation material that can conform to any space without disturbing structures or finishes.
This ability to conform makes loose-fill insulation well suited for retrofits and locations where it would be difficult to install other types of insulation. The most common types of materials used for loose-fill insulation include cellulose, fiberglass, and mineral rock or slag wool. All of these materials are produced using recycled waste materials. Cellulose is primarily made from recycled newsprint. Some less common loose-fill insulation materials include polystyrene beads and perlite.
Loose-fill insulation can be installed in either enclosed cavities such as walls, or unenclosed spaces such as attics. Cellulose, fiberglass, and rock wool are typically blown in by experienced installers skilled at achieving the correct density and R-values.
Polystyrene beads, vermiculite, and perlite are typically poured. The Commission issued the R-value Rule to prohibit, on an industry-wide basis, specific unfair or deceptive acts or practices. R-value ratings vary among different types and forms of home insulations and among products of the same type and form. For loose-fill insulation, each manufacturer must determine the R-value of its product at settled density and create coverage charts showing the minimum settled thickness, minimum weight per square foot, and coverage area per bag for various total R-values.
This is because as the installed thickness of loose-fill insulation increases, its settled density also increases due to compression of the insulation under its own weight.
Thus, the R-value of loose-fill insulation does not change proportionately with thickness. Unlike most common insulation systems, which resist conductive and convective heat flow, radiant barriers and reflective insulation work by reflecting radiant heat.
Radiant barriers are installed in homes -- usually in attics -- primarily to reduce summer heat gain, which helps lower cooling costs. Reflective insulation incorporates reflective surfaces -- typically aluminum foils -- into insulation systems that can include a variety of backings, such as kraft paper, plastic film, polyethylene bubbles, or cardboard, as well as thermal insulation materials.
Radiant heat travels in a straight line away from any surface and heats anything solid that absorbs its energy. When the sun heats a roof, it's primarily the sun's radiant energy that makes the roof hot. A large portion of this heat travels by conduction through the roofing materials to the attic side of the roof.
The hot roof material then radiates its gained heat energy onto the cooler attic surfaces, including the air ducts and the attic floor. A radiant barrier reduces the radiant heat transfer from the underside of the roof to the other surfaces in the attic. To be effective, it must face a large air space. Radiant barriers are more effective in hot climates, especially when cooling air ducts are located in the attic. The reduced heat gain may even allow for a smaller air conditioning system.
In cool climates, however, it's usually more cost-effective to install more thermal insulation. Rigid fiber or fibrous board insulation consists of either fiberglass or mineral wool material and is primarily used for insulating air ducts in homes. It is also used when there's a need for insulation that can withstand high temperatures. These products come in a range of thicknesses from 1 inch to 2.
Installation in air ducts is usually done by HVAC contractors, who fabricate the insulation at their shops or at job sites. On exterior duct surfaces, they can install the insulation by impaling it on weld pins and securing with speed clips or washers. They can also use special weld pins with integral-cupped head washers.
Unfaced boards can then be finished with reinforced insulating cement, canvas, or weatherproof mastic. Faced boards can be installed in the same way, and the joints between boards sealed with pressure-sensitive tape or glass fabric and mastic. Liquid foam insulation materials can be sprayed, foamed-in-place, injected, or poured. Foam-in-place insulation can be blown into walls, on attic surfaces, or under floors to insulate and reduce air leakage.
Some installations can yield a higher R-value than traditional batt insulation for the same thickness, and can fill even the smallest cavities, creating an effective air barrier. You can use the small pressurized cans of foam-in-place insulation to reduce air leakage in holes and cracks, such as window and door frames, and electrical and plumbing penetrations. Icynene plastic insulation blown into the walls of a home near Denver. Icynene fills cracks and crevices and adheres to the framing.
Today, most foam materials use foaming agents that don't use chlorofluorocarbons CFCs or hydrochlorofluorocarbons HCFCs , which are harmful to the earth's ozone layer. There are two types of foam-in-place insulation: closed-cell and open-cell.
Both are typically made with polyurethane. With closed-cell foam, the high-density cells are closed and filled with a gas that helps the foam expand to fill the spaces around it. Open-cell foam cells are not as dense and are filled with air, which gives the insulation a spongy texture. The type of insulation you should choose depends on how you will use it and on your budget. While closed-cell foam has a greater R-value and provides stronger resistance against moisture and air leakage, the material is also much denser and is more expensive.
Open-cell foam is lighter and less expensive but should not be used below ground level where it could absorb water. Consult a professional insulation installer to decide what type of insulation is best for you. Other available foam insulation materials include:. Some less common types include Icynene foam and Tripolymer foam. Icynene foam can be either sprayed or injected, which makes it the most versatile. Homeowners rely on this type of insulation—which is usually made of polyurethane, polystyrene, or polyisocyanurate—for both exterior and interior wall sheathing.
Foam boards work well to insulate everything from foundation walls and basement walls to unfinished floors and ceilings. R-values typically vary between R-4 and R Best for: Attics, unfinished walls, ceilings, and floors—especially in hot climates. Reflective or radiant barriers work differently than most types of insulation, and so its effectiveness is not measured by R-values. While standard insulation reduces heat flow in a home, reflective insulation instead reflects the heat away from the home to prevent heat gain and radiant heat transfer to cooler surfaces indoors.
The insulation is constructed using a reflective barrier like aluminum foil placed over a substrate material like kraft paper or polyethylene bubbles. Homeowners in warmer climates typically place reflective or radiant barriers in the attic between joists, rafters, and beams, since the attic is where most heat enters a home.
Installation here, too, can be done without a professional. Disclosure: BobVila. You agree that BobVila. All rights reserved. Expert advice from Bob Vila, the most trusted name in home improvement, home remodeling, home repair, and DIY.
Use this guide to determine the type of insulation that's right for you, creating a more comfortable and energy-efficient home.
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