Will PIR Insulation Help With Damp Or Moisture Issues In My Walls?

Yes, PIR insulation offers significant benefits in managing moisture, making it a strong ally against damp-related issues in building structures. A key characteristic of PIR is its predominantly closed-cell structure. This means that the individual foam cells are sealed off from each other, which inherently makes the material highly resistant to water absorption. Unlike open-cell insulations that can soak up moisture, PIR repels it, preventing dampness from penetrating the insulation layer itself. Many PIR boards are also manufactured with low-emissivity foil facings on both sides. These facings act as an effective vapour barrier, significantly reducing the passage of water vapour through the building element. By controlling moisture movement, PIR helps prevent interstitial condensation (where warm, moist indoor air meets cold surfaces within the wall or roof, causing condensation) and significantly reduces the risk of mold growth and structural decay due to dampness. This moisture resistance is crucial for maintaining the long-term thermal performance of the insulation and the overall health and integrity of your building.

What Is The Compressive Strength of PIR Insulation?

While primarily valued for its thermal properties, the compressive strength of PIR insulation is an important consideration, particularly for floor applications or areas subject to significant loads: What it means: Compressive strength refers to a material's ability to withstand compression (squashing) without deforming or breaking. For insulation, it indicates how well it can support the weight of superimposed elements like concrete screeds, floor finishes, or even foot traffic during construction.Why it matters: In ground floors, for instance, PIR boards must be robust enough to support the concrete slab and subsequent floor finishes without compressing over time, which could lead to structural issues or cracking in the finish.Typical values: PIR insulation typically has a high compressive strength, often exceeding 150 kPa (kilopascals), meaning it can withstand a pressure of 15 tonnes per square metre. Higher strength grades are available for areas with heavier loads.Application-specific: Always ensure the PIR board specified for your project has adequate compressive strength for its intended use, especially in load-bearing floor or flat roof applications. This information will be clearly stated on the manufacturer's technical data sheet.

How Does PIR Help Thermal Bridging?

Thermal bridging, also known as a "cold bridge," occurs where there are gaps in the insulation layer or where a more conductive material (like a timber stud or concrete lintel) penetrates the insulation. These areas act as pathways for heat to escape, leading to: Increased Heat Loss: Higher energy bills as more heat escapes the building.Cold Spots: Uncomfortable cold areas on internal surfaces, especially near windows, doors, or corners.Condensation and Mould Risk: Cold surfaces can lead to condensation forming, creating ideal conditions for mould growth. PIR insulation helps mitigate thermal bridging due to: High Efficiency: Its superior thermal performance means thinner layers can still provide excellent resistance, reducing the "depth" of potential bridges.Rigid Board Format: PIR comes in rigid boards that can be cut precisely and fitted tightly, minimising gaps.Edge Profiles: Many PIR boards are available with rebated edges or tongue-and-groove profiles that interlock, creating a more continuous and airtight insulation layer at joints.Use in Continuous Layers: PIR is often specified for "warm roof" or "external wall insulation" systems where it forms a continuous, uninterrupted layer of insulation outside the main structural elements, wrapping the building in an insulating blanket and minimising cold spots caused by timber or masonry.

What Are Some Common Misconceptions About PIR Insulation?

"Thicker is always better for insulation." While generally true for the same material, PIR's high efficiency means you can achieve equivalent or better performance with thinner boards than some other materials. It's about the thermal conductivity, not just the physical thickness."Insulation means no ventilation." False. Insulation reduces heat loss, but good ventilation is still crucial for healthy indoor air quality and to prevent moisture build-up from internal sources (cooking, showering, breathing). Insulation and ventilation work together."Any gap doesn't matter." A small gap might seem insignificant, but collectively, gaps in insulation (thermal bridges) can lead to substantial heat loss, cold spots, and condensation issues. Continuity and airtightness are paramount for insulation effectiveness."Insulation only works in winter." Incorrect. While we often think of insulation for keeping warm, it's equally effective in summer. It prevents unwanted heat from entering your home, keeping it cooler and reducing the need for air conditioning, saving energy year-round."Insulation is only for old houses." All buildings, new or old, benefit from good insulation. Modern building regulations require high levels of insulation in new builds, and retrofitting insulation in older homes is one of the most effective ways to improve their energy performance.

PIR Insulation Boards | Materials Market

How to Insulate Under Floorboards Without Removing

23 October 2023

How to Insulate a Shed

23 October 2023

Cavity Wall Insulation Installation

03 October 2023

Cavity Wall Insulation Problems

27 September 2023

Cavity Wall Insulation Cost

26 September 2023

How To Install Celotex Insulation Boards

17 May 2022

Insulation Installation Safety Precautions

09 April 2022

Insulation Installation Equipment - What Do I Need?

19 March 2022

Celotex Floor Insulation Guide

19 March 2022

PIR Insulation Board

Manufacturer

Material type

Thermal conductivity

Width

Thickness

Related Articles

How to Insulate Under Floorboards Without Removing

How to Insulate a Shed

Cavity Wall Insulation Installation

Cavity Wall Insulation Problems

Cavity Wall Insulation Cost

How To Install Celotex Insulation Boards

Insulation Installation Safety Precautions

Insulation Installation Equipment - What Do I Need?

Celotex Floor Insulation Guide

All Categories

Insulation Boards

Insulation Slabs

Insulation Rolls

Material Type

Applications

Insulation Accessories

Plasterboard

Insulated Plasterboard

Metal Studs & Ceilings

Bagged Products

Other Boards

Drylining Accessories

Treated Timber

Sheet Materials

CLS Timber

Planed Timber

Loft Boards

Cladding

Sand & Aggregates

Cements & Limes

Bricks & Blocks

Lintels

Builders Metalwork

Drainage

Internal Doors

External Doors

Skirting & Architrave

Windows

Door Frames

Fencing

Decking

Landscaping

Driveways & Paving

Lead Flashing

Pitched Roofing

Flat Roofing

Fascias & Soffits

Guttering

Roof Tiles & Slates

Plasterboard Fixings

Wood & Timber Screws

Fixings & Fasteners

Insulation Screws & Fixings

Nails & Anchors

Nuts, Bolts & Washers

Glues & Adhesives

Silicone & Sealants

Tapes

Foams & Fillers

Power Tool Accessories

Hand Tools

Site Supplies

Packs of Timber

Packs of Sheet Materials

Packs of Blocks

Loose Sand & Aggregates

Pallets of Cement

Pallets of Insulation

Pallets of Plasterboard

Pallets of Bagged Products

Services