Most underfloor insulation jobs are fairly straightforward. You measure the gap between the joists, add 20mm to that, order that width of insulation, staple it snugly into place, and move on to the next bay.
Lovely. Except, of course, when the joists are not standard. Some homes have one or two awkward joist bays. Some vary from room to room. Some appear to have been built by someone who had no obvious relationship with a tape measure.
So what happens when standard underfloor insulation does not neatly fit your floor?
First, the snug fit matters
Standard Value Poly Underfloor Insulation is 450mm wide, which is designed for joists with a 430mm gap between them.
That extra 20mm is deliberate. Polyester underfloor insulation should be slightly wider than the space between the joists so it can be stapled snugly into place. As a general rule, the insulation should be 20mm wider than the joist space.
For example: If your joist space is 430mm, your ideal insulation width is 450mm.
That snug fit is important because underfloor insulation cannot be stretched if it is too narrow. And if insulation is bunched, squashed, or loose, it can leave gaps for cold air, reduce thermal performance, and make it easier for rodents to get into the space above the insulation.
Polyester underfloor insulation only works properly when it is fitted properly.
What if your joist spacing is not standard?
If you have non-standard joist spacing, your first option is usually turn-and-tear.
Turn-and-tear is how professional installers deal with variable joist widths. The insulation is turned, torn or cut to the width needed, and stapled neatly into the joist bay. For some reason, it sounds too hard to do, but it is a professional installation method. It also tends to get a worse reputation than it deserves.
In most cases, turn-and-tear only adds around 15% more time compared with a standard installation. So before you assume custom cut insulation is the answer, it is worth thinking carefully.
When turn-and-tear is the better option
Turn-and-tear is usually the better choice if:
- you only have a few awkward joist bays
- your joist spacing varies all over the place
- your job is under 100m²
- you need the insulation quickly
- you are happy to make small adjustments on site
If your installer is coming tomorrow, custom cut insulation is not the answer. Turn-and-tear is your friend.
When custom cut insulation may make sense
Custom cut Value Poly may make sense if you have a large area with the same non-standard joist spacing. This is the key point.
Custom cut is not designed for one outlying bay. It is not designed for a house where every joist space is doing something different. It is for repeated non-standard spacing across a large area.
If you have 100m² or more in the same odd width, custom cut Value Poly may save your time.
Custom cut Value Poly rules
Custom cut Value Poly is a special-order product.
The rules are:
- Location: Victoria and Perth only
- Minimum order: 100m² per custom width
- Custom cut set-up fee: $400 per custom width
- Delivery: to your door only
- Pickup: not available
- Returns: not available
- Timing: not a rush order
Custom cut orders need to be fitted into the manufacturing schedule. They are not suitable for urgent installations.
One width means one order
If you need two different widths, each width needs to meet the 100m² minimum, and each width attracts a separate $400 custom cut fee.
You cannot combine different widths to make up the 100m² minimum.
For example:
Yes: 100m² at 410mm wide
No: 50m² at 410mm wide and 50m² at 430mm wide
Yes: 100m² at 400mm wide and 100m² at 490mm wide
Each width is treated separately.
Measure carefully
Custom cut insulation is made to your measurements. That means there are no returns if the width is wrong, the joists are different from what you thought, or the house has pulled one of its little surprises. Measure properly across the whole floor. Check several areas. Then measure again. If the joist spacing varies, custom cut may not be the best answer. Turn-and-tear may still be more practical.
Is custom cut available for Polymax?
No. Custom cut underfloor insulation is available for Value Poly only in Victoria and Perth. It is not available for Polymax Underfloor Insulation.
So, should you choose custom cut?
Choose turn-and-tear if you have a few odd joist bays, mixed joist spacing, a smaller job, or a tight timeframe.
Choose custom cut Value Poly if you have a large area with the same non-standard spacing, need at least 100m² in that width, and are not in a rush.
Need custom cut Value Poly?
Send us:
- the custom width you need
- the square metres required
- your delivery address and contact details
- any other widths you are considering
Contact us by chat at www.ecoMasterStore.com.au, email sales@ecomaster.com.au, or call 1300 326 627.
We will let you know what is possible.
Recent Comments