Why Pecasa Uses 122 mm SIP Panels — The Smartest Structural Choice for Modern Garden Rooms in the UK

 Today's garden rooms aren't just garden buildings anymore. They're insulated garden rooms that can be used all year round. The way the rooms are built determines how the rooms will perform, how long they will last, and how they'll continue to save energy over time.

Pecasa makes the structural choice to use 122 mm Structurally Insulated Panels (SIPs). This thickness offers one of the best compromises and overall value in the UK, due to the combination of strength, insulation quality, and the design options that it offers.

This guide explores the reasons why SIP panels are built, and why the 122 mm thickness is the most used in the UK.

What Are SIP Panels?

SIPs, or Structurally Insulated Panels, are composite building panels. This means that they are made of 3 different components, with an insulated center and two boards, usually OSB3, on the outsides. Once the panel is manufactured, the panel acts as a single structural piece. This means that it can provide strength like a beam, as well as insulation like a fully insulated wall.

Instead of building a wall with traditional wood framing, SIPs offer the advantage of building a fully insulated wall that makes the building airtight and protects the structure from energy loss.

Why 122 mm SIP Panels Are the Ideal Thickness

⚖️ The Perfect Balance Between Strength and Insulation

There are several panel thickness options, and 122 mm is a popular thickness standard because it offers the thermal insulation needed without creating enormous wall thickness.

Standard performance benchmarks:

• 97 mm panels have a U-value of 0.27-0.30 

• 122 mm panels have a U-value of 0.22 

• 147 mm panels have a U-value of 0.17 

Hence, compared to thinner panels, 122 mm panels significantly improve insulation, all the while maintaining efficient building proportions. 

This is great for garden rooms and annexes, as it offers a balance, providing comfort all year, without having walls that are too thick. 

🔥 Enhanced Energy Efficiency for the U.K. Climate 

SIP panels improve insulation and significantly decrease unwanted heat loss due to the minimized thermal bridging. 

Also, compared to traditional timber frames, SIP walls have a reduced number of structural studs within the frames. Which, in turn, reduces cold bridging and improves the airtightness of the walls. 

This helps to stabilize more constant internal temperatures, lower energy costs, and requires less heat, all while reducing heat losses to the exterior. 

Modern outdoor living spaces are best created using 122 mm SIP construction, as it provides most of the above, as well as providing: 

🧱 Enhanced Structural Performance   

122 mm SIP panels also provide insulation, as well as structural performance. The rigid insulation core, as well as the bonded OSB skins, allows the panels to provide structural performance and support high loads, as though they are structural beams.

Due to the panel's load-bearing capabilities:

·         Less internal support is needed -

·         More expansive open-plan spaces can be created

·         Achieving sleek architectural design is easier

·         Factory-made panels' precise fabrication also reduces construction gap.

·         ⚡ Construction is faster and more precise

Traditional timber frame construction requires multiple steps - there is framing, insulation, membranes, and sheathing. SIP construction simplifies this by combining these multiple layers into a single engineered panel.

The benefits of this include:

·         Quicker installation

·         Increased construction precision

·         Less on-site waste

Many SIP constructions can be finished much quicker than more traditional constructs as an entire panel is ready to be installed.

💧 Air control and moisture management

The unique bonding in SIP creates an entire assembled panel that's more airtight. This unique design minimizes air leakage, providing the insulation more protection and improving overall structure comfort.

The precision manufacturing and the tightly bonded joints that SIP uses minimizes the gaps that could allow moisture or heat loss to remain. This degree of airtightness is critical in areas that face the UK weather.

Why Pecasa also chooses 122 mm SIP panels.

Although there are thicker panels available, Pecasa focuses on the 122 mm SIPs because these panels are best suited to the garden rooms and living annexes.

Key Benefits:

·         Insulation performance makes it suitable for all-year use.

·         It has a slim wall profile, maximising internal space.

·         It offers structural strength for tailored architectural preferences.

·         It has effective interoperability with high-end cladding systems.

·         Focus on building solidity and comfort, without excessive bulk or complexity.

Comparison of SIP Panels vs Trad. Timber Frame:

Feature	122 mm SIP Panels	Traditional Timber Frame
Insulation continuity	Continuous core	Interrupted by studs
Airtightness	High	Variable
Construction speed	Fast	Slower
Structural strength	Integrated panel	Separate frame system
Thermal bridging	Reduced	More common

Since SIPs combine insulation and structure, they outperform standard timber frame walls in energy efficiency.

SIPs that are 147 mm or 222 mm may be able to obtain some of the highest U-values, but may not be a necessity for garden rooms.

SIPs that are 147 mm or 222 mm may:

·         Increase wall thickness

·         Reduce internal useable floor space

·         Increase costs unnecessarily if the garden room is small

122 mm SIP Panels balances optimum performance and practicality while being the most cost effective for most building garden rooms in the UK.

Why SIP Construction Is So Effective with Pecasa Designs

Pecasa garden rooms use 122mm SIP panels to create warm, inviting spaces to live in, which leads to the following benefits:

(Design) flexibility

(Build) efficiency

(Perform) reliability

(Last) structural (performance)

The end product is a garden room that performs like it is part of the home.

122 SIP Panel Questions

Are garden rooms with 122 mm SIP panels energy-efficient?

(SIP) panels have a (U) value of 0.22 or less, SIP panels (provide) a garden room with great (thermal) performance.

Are SIP panels stronger than timber frames?

The insulation and structural components of a SIP panel are combined into one, therefore eliminating some thermal bridging (and) increasing structural rigidity.

Why not use thinner a panel?

Thinner panels provide less insulation, which can reduce comfort and energy (consumption) efficiency.

Are thicker panels always better?

Not always. 122 mm panels often provide the best (combination) of performance, cost, and (space) efficiency.

Considering a SIP Garden Room?

Your choice of construction system influences the initial and the long term experience of the customer with the garden room. At Pecasa, we aim for precise and high-performance garden spaces throughout the UK. We address this with 122 mm SIP panels as they offer a balanced solution with regards to insulation, strength and design versatility.