About a third of your home’s heat is actually lost through the floor, so underfloor insulation is just as important as ceiling and wall insulation. Underfloor insulation is easy to install, and there’s no reason why you can’t do it yourself. This guide will show you how to get it done, so you can enjoy a warmer, drier, and healthier home.
It’s a good idea to get an electrician to check the condition of your wiring – especially if you’ve got an older house. You’ll also want to check for any leaking pipes, and make sure you get any repairs done prior to starting.
Familiarise yourself with “NZS4246 - Installing Insulation in Residential Buildings” – you can find this online. Because you are working close to wires, you’ll need to turn off the power. Take note of how long your fridge or freezer will be off. Inside or on you insulation packs there should be exact instructions for installation. Its a good idea to read these.
Depending on what part of the country you live in will determine your insulation’s R Value. The R Value is simply a measure of the insulation’s effectiveness. In colder regions the R Value needs to be higher - your local store will stock the correct product for your area.
In this guide we’re using GreenStuf Blanket Underfloor insulation. It comes in 3 widths (450mm, 500mm, & 600mm), so you’ll need to select the right one for your situation.
Measure the distance between your joists and select the correct product width. Measure between more than one joist, as in old houses the width may vary.
Choose the product width that is at least 50mm wider than your average joist gap. Measure your floor area then check the pack for coverage information. This will help you determine how many packs you’ll need.
