Methods for Insulating Extensions: Discover Your Choices, Detailed in Our Guide
In the process of extending your home, insulation plays a crucial role in ensuring comfort and positively impacting existing spaces. Furbnow, a company promoting best practices on the environmental, social, and economic aspects of sustainable housing, provides insights into the best types of insulation and methods for incorporating them into an extension.
Walls
When insulating the walls of an extension, it's essential to use insulation batts or rigid boards that fit well into wall cavities without compressing, maintaining thermal performance. For period properties, consider breathable insulation materials that minimize trapping moisture, such as natural wool or hemp, to avoid damage to older masonry walls. Ensuring any insulation addition to solid walls manages moisture correctly to prevent condensation and decay is crucial.
Roof
Two main roof insulation types are warm roofs (insulation above roof structure) and cold roofs (insulation below roof space). Warm roofs reduce the risk of condensation, providing a continuous thermal envelope, but can be more costly. Cold roofs rely on ventilation to avoid moisture buildup but may pose condensation risks and require careful design.
For period properties, warm roofs are often preferred due to better moisture control and preservation of historic roof timbers. However, local building codes and architectural considerations are critical. Common insulation materials for roofs include rockwool, glass wool, or performance boards, often paired with vapour barriers or membranes to control moisture.
Floor
The type of floor insulation depends on the floor construction. Suspended timber floors can use batts or rolls such as polyester or glasswool that resist moisture and mold. Concrete floors benefit from thin, high-performance boards like radiant foam insulation or ultralight rigid boards that improve thermal retention without excess thickness. For period properties, underfloor insulation must ensure moisture control and allow the floor to breathe, sometimes favoring breathable insulation or using membranes carefully to avoid trapping moisture in historic buildings.
Key General Factors to Consider
- Moisture control and ventilation: Critical to avoid condensation, mold, and damage, especially in older constructions.
- Building regulations: Compliance with local codes is mandatory and might influence insulation choices and installation methods.
- Thermal efficiency vs. preservation: Balancing energy savings with the need to protect historic features.
- Material suitability: Insulation materials should be compatible with the extension’s construction and use.
Variations for Period Properties
Older properties often have solid walls and breathable materials, requiring insulation methods that manage moisture without causing decay. Typically, avoid impermeable materials (like certain foams) that trap moisture. Retain original features by using plasters and insulation that allow vapor permeability. Consult specialists to ensure that insulation respects both thermal performance and heritage conservation requirements.
When building an extension, homeowners should consider the requirements based on the planned use and the style and age of the existing house. Insulation materials can cost anywhere from £20 to £50 per square metre, with installation costs on top. Older homes with solid walls may require insulation to tie in with the existing structure to avoid thermal bridging issues.
In summary, the best insulation method combines a well-chosen material offering thermal resistance, moisture management, and compatibility with the extension's construction type. For period properties, breathability and careful moisture control become paramount, often making natural or flexible insulation materials preferable and necessitating expert input on suitable solutions.
[1] Furbnow (2022). Insulating Period Properties: A Practical Guide. Retrieved from https://www.furbnow.co.uk/insulating-period-properties-a-practical-guide/
[2] Passivhaus Trust (2021). Insulation in Passivhaus Buildings. Retrieved from https://www.passivhaustrust.org.uk/resources/technical-guides/insulation-in-passivhaus-buildings
[3] Building Regulations (2019). Approved Document L1B. Retrieved from https://www.gov.uk/government/publications/conservation-of-fuel-and-power-in-dwellings-approved-document-l1b
[4] National Insulation Association (2020). Insulation for Warm and Energy Efficient Homes. Retrieved from https://www.nationalinsulation.org/news/insulation-for-warm-and-energy-efficient-homes/
- In the extension of your home, use insulation batts or rigid boards that fit perfectly into wall cavities, prioritizing materials that won't compress, preserving thermal performance.
- For period properties, opt for breathable insulation materials like natural wool or hemp to minimize moisture trapping in older masonry walls.
- To prevent condensation and decay, ensure any additional insulation to solid walls is installed correctly, managing moisture effectively.
- When choosing between warm roofs and cold roofs, consider their pros and cons regarding moisture control, cost, and compliance with local building codes.
- For suspended timber floors, use batts or rolls of materials that resist moisture and mold, such as polyester or glasswool.
- Concrete floors benefit from thin, high-performance boards like radiant foam insulation or ultralight rigid boards that enhance thermal retention without excessive thickness.
- Comply with local building codes and ensure contractors follow proper insulation and installation methods to avoid any issues with thermal bridging.
- Consult specialists for advice on suitable insulation solutions for period properties, focusing on breathability and moisture control to preserve heritage features.
- When planning an extension, factor in the costs of various insulation materials, which may range from £20 to £50 per square metre, and anticipate additional installation costs.
- To create a comfortable living environment, efficiently manage energy consumption, and maintain the aesthetic appeal of your home and lifestyle, refer to guides on home-and-garden websites and home-improvement publications for tips on successful insulation projects.
