Home insulation

Home owners spend a lot of money on heating and cooling the home yet home insulation offers an affordable and energy efficient way to keep a home cool or warm. The money that you spend on buying or installing home insulation will not only reduce your monthly expenses, it provides year-round comfort.


Added to that, every homeowner can contribute towards a greener lifestyle and enjoy the benefits of comfortable living simply by installing home insulation.

Warm air naturally flows to cool spaces, through ceilings, walls, doors and floors. During the winter months, heat in our home travels to the cold exterior, and during the summer, heat outside of our homes travels to the cooler interior. We, in turn, use various types of energy to heat or cool the home. Home insulation is designed to slow down the transfer of heat by creating a layer of resistance to warm air, effectively blocking out heat transfer through the ceiling during the summer months and retaining heat in a home during the winter months.

Home insulation is graded according to R-value. The R-value is a measure of the thermal resistance of a particular material, and indicates the thickness of the material and its thermal conductivity or ability to block out heat. When considering the installation of home insulation it is important to ascertain the R-value of the product to be fitted and what is best suited for your climatic region.

The proper installation of insulation is just as important as its R-Value. Compressed insulation provides less resistance to heat flow than the rated value of its natural, fluffed form. The benefits of thermal insulation are only realised when insulating materials of correct R-value and maximum thickness is employed, thus generating energy-saving benefits.

Home insulation is a fairly simple do-it-yourself project that requires only basic tools and materials for a project that can easily be completed in a day. Your local building warehouse store carries a range of home insulation, as well as any tools needed to install it.


Correct R-value insulation material* [see table for your specific region]

Stepladder for access to ceiling space

Utility knife

Saw or long, serrated edge knife

Dust mask

Long-sleeved T-shirt and long pants

Thick gloves

Portable light

*To calculate how many packs of insulation required you will need to work out the square metre area that you intend to insulate. Draw up a basic plan of the outside of your home and measure the perimeter; multiplying the length by the width to give the total area in square metres. 

TIME: 1 to 2 day

COST: R2000 for a standard 3-bedroomed house



When entering the attic or ceiling space, take extra care to walk or stand on joists only. Joists are the long, thick beams that run horizontally from one wall to the next.


Don suitable clothing for the job at hand. Fibreglass or other insulation materials can cause severe itching, so wear gloves, long pants and a long-sleeved top, plus a dust mask. Set up a portable light to provide sufficient illumination for you to be able to work safely.

1. Use a tape measure, pencil and notepad to write down the measurements for each strip that needs to be cut. You are going to be cutting quite a few sections, but concentrate in one area at a time so that you can stay organised and on top of everything.

2. It is far easier to work with one roll of insulation material at a time, as you will be working in a confined ceiling space. Use a saw or large sharp knife to cut the sections to size and carry cut strips up as you need them. Each strip should be 50mm wider than the space between the joists, to allow it to fit snugly between joists.


Have a space for cutting, preferably in a garage or outdoors, as the cutting can be a messy process.

3. Start at the furthest corner and unroll the insulating material and place over the ceiling, between main ceiling joists. Remember to only stand or support yourself on main beams over the area where you will be working.


Allow a 30mm clearance gap around any vents, electrical fittings such as downlights, or chimney.

4. The insulation should be placed under any electrical cables to ensure that there are no air cavities. Ultimately, you want to have no gaps whatsoever between the joists, or where you have cut insulation material.

It is imperative to lay the product so that no cavities or channels form due to compression or improperly attached insulation, as this will allow unwanted air and heat movement to occur within that cavity.

5. Where there are pipes in the ceiling space tear the insulation to fit around pipes and conduits.

6. After the roll is laid in place, use your gloved hand to tuck the sides down gently. For proper insulation there should be no gaps left open between joists, and all edges must be tucked down.

Note: The ceiling insulation project was completed two days prior to a cold snap that we had, and I must be honest and say that the effect was dramatic. The bathroom, normally a cold room, was much more comfortable.