types of CAVITy Wall insulation - Basics

Millions of cavity wall homes do not have enough insulation (or insulation at all). Insulating those cavities properly is crucial to get energy-efficiency, comfort and to reduce heating and cooling bills.

Types of Wall insulation

Cavity wall insulation in crucial either in existing homes and new homes.

There are two main types of wall cavities. Stud cavities (typical of wood frame homes...) and the gap cavities of brick and masonry homes with two layer-walls. See pictures below.

But though very important, cavity insulation doesn't prevent heat and cold to pass through studs and other non-insulated wall components like ducts or pipes...

To stop that thermal bridging, the surface of the outer walls should also be covered with a convenient continuous layer of insulation (foam nsulated sheathing). That's a second, and very important, type of wall insulation.

New types of wall insulation

Cavity wall insulation and Wall Insulated Sheathing are the most common types of wall insulation. But they are now being challenged by more modern types of wall construction and insulation, namely the ICF forms (Insulated Concrete Forms) and SIP wall construction.

In these cases, insulation is included in the building materials themselves, with excellent results in terms of energy-efficiency. There isn't, in these cases, a gap/cavity to be filled by insulation...

Types of wall Cavities

Steel and wood-frame walls have stud cavities (first picture) that should be properly and wholly insulated.

Most brick, cement-block and other 'cavity walls' have also cavities (the gap between their two layers: second picture, below), which also require insulation.

Types of Cavity Wall insulation Materials

Cavity wall insulation is existing homes is usually made out of three types of materials:

- Loose-fill insulation materials
Cavity Wall and its Insulation - Sprayed-on fiber insulation
- Sprayed on Foams

In new homes cavity insulation can also use fiberglass, cellulose and rockwool batts, or the more modern and energy-efficient rigid foam batts.

Types of Cavity Wall Insulation Audit

If you don't know the exact insulation in your walls, you may demand a professional audit to them (see: Home Insulation Audit Basics), or make a quick assessment yourself.

To inspect the wall insulation you may remove one (or a few) small sections of The cavity in the two-layers wall only partially prevent thermal briding; this type of wall should be insulated in its gap/cavity the exterior siding, or drill a hole in a hidden and convenient location - away from electrical wiring - and use a plastic crochet hook or something alike to check the wall insulation.

Another technique involves the electrical outlets on the wall (be sure to turn off the power). Just remove the cover plate of an outlet and inspect the crack around it: shine a flashlight into the crack; repeat the same inspection in other outlets, to assess the situation in other rooms and parts of the house.

Obviously, these simple types of auditing do not replace a professional audit in more demanding and complex cases.

The cavity wall is insulated, preventing thermal bridging. Insulation is crucial in the two-layers type of walls

Types of cavity Insulation

Either in the case of brick and block walls with a gap/cavity, or in traditional wood frame wall, the most common type of cavity insulation involves drilling small holes (around 1 inch; 2-3 cm in size) at regular intervals (of around 3-5 feet; 1 m - 1.5 m) and blow insulation into the cavity, using proper equipment.

See for details: Blown cavity insulation and Cavity Insulation Problems

Cavity wall insulation costs and prices

The prices of cavity wall insulation varies with the type of insulation material, the type of wall and also, strongly, with the type of works demanded or associated to the cavity wall insulation. See: Cavity insulation prices and costs