Achieving Passive House Standard with SIPit Panels in Scotland’s New 2027 Building Regulations

Scotland’s 2027–2028 building regulations are moving toward a Scottish Passivhaus‑equivalent standard, with significantly tighter fabric performance requirements. This signals a clear shift to lower U‑values, higher airtightness, reduced thermal bridging, and lower embodied carbon.

Many construction systems will need multi‑layer insulation build‑ups to meet these new targets. SIPit’s PU SIP panels do not.

Our large-format PU SIPs achieve these U‑values as a single engineered panel, simplifying construction, reducing cost, and improving consistency.

Likely Scottish U‑Values for 2027–2028:-

Based on consultation direction and industry modelling, Scotland is expected to adopt:

• Walls: 0.10–0.13 W/m²K

• Roof: 0.08–0.10 W/m²K

• Floor: 0.10–0.12 W/m²K

• Windows: 0.80 W/m²K (whole window)

• Doors: 0.80–1.0 W/m²K

• Airtightness: ≤ 1.0 m³/m²·h @ 50 Pa

These figures align with Passive house standards.

SIPit PU SIP Panels: Single‑Panel Passive House Performance:-

• 195 mm PU SIP — 0.12 W/m²K

Suitable for walls under the new Scottish standard. Achieves Passive House‑level performance without additional insulation.

• 220 mm PU SIP — 0.11 W/m²K

Ideal for walls or roof assemblies.

• 245 mm PU SIP — 0.10 W/m²K (panel only)

And 0.09 W/m²K when installed with framing and plasterboard. This meets the tightest expected Scottish roof U‑values.

These panels allow designers to meet the new Scottish fabric targets with a single engineered panel, avoiding multi‑layer insulation systems entirely.

Why PU SIPs Achieve These U‑Values Without Multi‑Layer Build‑Ups:-

1. High‑performance PU core

PU insulation has one of the best thermal conductivities of any rigid insulation. This allows SIPit panels to achieve low U‑values at thinner thicknesses.

No secondary insulation layers required. Due to its high performance, our PU SIP construction system is carbon negative in 1 to 3 years

2. Structural strength = less timber

PU SIPs require less internal timber because the core carries more load.

Less timber means:

• Lower Psi values

• Reduced thermal bridging

• Better PHPP modelling

• Lower heating demand

• Less reliance on timber

This is a major advantage over systems that rely on timber-heavy framing.

3. Large-format panels = fewer joints

SIPit PU SIPs are manufactured in large formats, reducing joint count by up to 50%.

Fewer joints =

• Better airtightness

• Fewer leakage paths

• Faster installation

• More predictable blower door test results

This supports Scotland’s likely airtightness target of ≤ 1.0 m³/m²·h.

4. Insulated splines remove a common cold bridge

Our insulated spline system replaces traditional timber splines.

This eliminates a major cold bridge found in many panel systems and improves:

• Thermal continuity

• Comfort

• Energy demand

• PHPP results

5. Special junction details remove cold bridging entirely

SIPit has developed detailing that avoids cold bridging at:

• Wall‑to‑roof junctions

• Openings

• Corners

• Sole plates

• Eaves and ridges

These details allow the PU SIP envelope to perform as modelled — without needing extra insulation layers to “fix” thermal bridges.

6. Slimmer walls = smaller foundations + lower carbon

Because PU SIPs achieve low U‑values at thinner thicknesses, foundations can be smaller.

This reduces:

• Concrete volume

• Embodied carbon

• Excavation cost

• Build time

Slimmer walls also increase internal floor area.

7. Single‑panel delivery = lower transport emissions

Because SIPit PU SIP panels achieve Scotland’s new U‑values as a single engineered panel, they avoid the need for multi‑layer insulation systems that require several different products to be transported separately.

This means:

• Fewer deliveries

• Lower transport emissions

• Reduced site congestion

• Simpler logistics and scheduling

A single PU SIP panel replaces what would otherwise be multiple pallets of insulation, additional timbers, and supplementary materials — reducing carbon and cost before construction even begins.

To Summarise why SIPit PU SIP provides an effortless solution to the new Regs:-

SIPit’s 195 mm, 220 mm, and 245 mm PU SIP panels provide a streamlined, high-performance route to Scotland’s upcoming 2027–2028 building regulations:

• Walls: 195 mm panel at 0.12 W/m²K

• Roofs: 220 mm panel at 0.11 W/m²K

• High-performance roofs: 245 mm panel at 0.10 W/m²K (0.09 W/m²K installed)

• No multi-layer insulation required

• Slimmer walls, smaller foundations, less timber

• Reduced thermal bridging and insulated splines

• Special detailing that removes common cold bridges

• Lower embodied carbon and transport emissions

• More airtight and easier to detail around openings

  
  

SIPit PU SIPs are already aligned with Scotland’s future building standards — delivering a practical, efficient, and sustainable solution for high-performance homes.

Email info@sipit.uk for more information