All over H1 edging

To ensure our builders remain ‘All Over H1’, PlaceMakers is committed to reporting on the latest product solutions designed to meet the requirements of Clause H1 of the New Zealand Building Code – including these concrete slab edge insulation options from Firth and QuickSet 

While many builders are now familiar with H1 requirements – most of which came into force last year – others are encountering the changes for the first time. This is largely due to the lag time between consents and builds, with any consents issued before 1 May 2023 still able to use previous requirements. With this in mind, we’ve included below a reminder on the current construction R-values for floors.

H1 changes for floors

Increases to floor insulation are two-fold, differing over climate zone – as with all building elements – but also  depending on whether you have a concrete slab-on-ground floor or another type (most commonly suspended floors).

The new minimum construction R-values are lower – R1.5 to R1.7 – for concrete slab-on-ground floors than for other floor types – R2.5 to R3.0. According to MBIE, this is because it’s much more challenging for slab-on-ground floors to achieve significantly higher R-values than with other types, such as suspended timber floors.

However, even the small increase required for unheated slab-on-ground floors in the warmest four climate zones – a move from R1.3 to R1.5 – is greater than it appears.

That’s because the background calculation method used for the 5th edition has changed. According to  BRANZ, the increase is the equivalent of going to R2.0 under the previous approach. R1.5 means most slabs in buildings under 300m² will be specified with some combination of perimeter and under-slab insulation.

In the future, MBIE expects that this differentiation between the floor types to be removed and slab-on-ground floors will need to achieve even higher levels of insulation.

It’s unlikely that there will be a big shift in the types of products that can be used, but a change in the installation methods will be needed. For example, insulation added to non-slab-on-ground floors will no longer be able to be held in place with staples due to its increased thickness.

The new R-value requirements are also different for heated slab-on-ground floors. See the table below.

More than 80% of heat loss from a concrete slab foundation is lost through the edges, which is why insulating these surfaces is important for creating an effective thermal envelope to reduce energy demands for both heating and cooling. Firth and QuickSet have developed products to help resolve this issue.

New supplier solutions

Firth’s proven RibRaft HotEdge®

Firth’s proven RibRaft HotEdge® slab insulation solutions have options for all cladding types:

• HotEdge (BV) for brick veneer cladding.
• HotEdge Extra for non-brick veneer cladding.
• HotEdge Base for under slab perimeter insulation.

With Firth HotEdge® or HotEdge Extra®, you are not only helping to create warmer, drier, healthier homes, you’re also allowing for design freedom elsewhere in the build with HotEdge helping to meet (or exceeding) H1 requirements.  

HotEdge Extra provides peace-of-mind with a BRANZ-tested installation solution (ST18050) for anchoring 90mm timber framing base plates to the slab. 

The HotEdge systems help close a building’s thermal envelope to create a healthier home by removing thermal bridging cold spots where the slab and timber framing meet.

The HotEdge system is quick and easy to use, with a pre-plastered finish on the XPS boards, easy-to-fit Tornado screws and powder-coated aluminium corners, all designed to reduce installation time and costs. Each board has two standard heights with custom board heights available up to 1000mm.

HotEdge is a fully integrated thermal solutions that has been tested with all Firth RibRaft foundation systems and RaftMix concrete to ensure your slab meets or exceeds H1 compliance.

QuickSet Concrete Slab-Edge Insulation

QuickSet is excited to announce the launch of QuickEdge edge insulation for concrete foundations, tailored for those who prefer
tried-and-tested traditional boxing methods but seek the advancements of modern solutions. 

While the concrete slab edge insulation was already available as part of its patented QuickSet system, the company is thrilled to bring the benefits of edge insulation to those using traditional concrete slab methods.

QuickEdge is proudly CodeMark-certified and BRANZ-appraised in conjunction with Allied Superslab+. 

There are three options to suit varying traditional slab methods, and all deliver superior thermal performance:

• QuickEdge Taper, designed for 90mm framing, has an R-value close to R1.0.
• QuickEdge Ultra, designed for 140mm and above framing, has an R-value that exceeds R1.0.
• QuickEdge Brick, designed for brick homes, has an R-value close to R1.0.

Designed to deliver exceptional performance at an affordable pricepoint, QuickEdge is pre-finished with UV stabilisers built into it and does not requiring plastering, priming or painting – saving time and labour costs.

With durability in mind, QuickEdge is built to survive the rigours of construction and the bustling activity of home life. Thanks to a dense outer layer, protecting the softer insulation material on the inside, it’s protected from weed eaters, lawn mowers or crickets balls!