How to choose a fiberglass mat for roofing based on the density of the glass fiber

1. The concept of fiberglass mat density
The density of Fiberglass Tissue Mat for Roofing refers to the mass of glass fiber contained in a unit area, usually expressed in grams per square meter (g/m²). The density directly affects the mechanical properties, compressive strength, water absorption, thermal conductivity, etc. of the mat. In simple terms, the higher the density, the tighter the structure of the mat, and the higher the overall strength and stability. Conversely, a mat with a lower density is lighter and softer, and is suitable for occasions where strength requirements are not high.

2. The relationship between density and mat performance
Density directly affects several key properties of the mat, including:

(1) Tensile strength and compressive strength
High-density fiberglass mats usually have stronger tensile strength and compressive strength. This is because the glass fibers in high-density mats are more tightly interwoven, forming a stronger supporting structure. Therefore, high-density thin blankets are suitable for roof systems that are subject to large external forces, such as industrial buildings, commercial buildings, etc., and can effectively prevent the roof from deforming due to external loads or weather.
Although low-density thin blankets are lighter, they are weaker in strength and durability. They are usually suitable for roofs in low-load or non-exposed environments, such as small houses, sheds, etc.
(2) Water resistance and water absorption
The structure of high-density fiberglass thin blankets is tight and water is not easy to penetrate, so it has good waterproof properties. This is crucial for roofing materials, especially in rainy or humid areas. Thin blankets with strong waterproof properties can effectively prevent moisture from penetrating into the roof structure, avoiding mold growth and structural corrosion.
Low-density thin blankets have strong water absorption and water is more likely to penetrate, thus affecting the waterproof effect of the roof. Especially in rainy seasons or areas with heavy humidity, the use of low-density thin blankets may cause moisture and aging of the roof structure.
(3) Weather resistance and UV resistance
High-density Fiberglass Tissue Mat for Roofing is usually more weather-resistant and can withstand extreme weather conditions, including high temperatures, strong winds, and UV radiation. This is because the structure of high-density mats is more stable and can effectively prevent material degradation or cracking caused by UV radiation or temperature changes.
Low-density mats are more susceptible to UV rays and temperature changes due to their loose structure. Long-term exposure to the external environment may cause surface aging and performance degradation.
(4) Construction convenience
High-density fiberglass mats are stronger and easier to cut and lay during construction. Especially in large-area roof construction, higher density can provide better stability and tensile resistance, reducing breakage and deformation during construction.
Low-density mats are softer and may be more flexible during construction, but due to their lower strength and durability, extra care is required during construction to avoid damage.
(5) Weight and convenience
High-density mats are usually heavier because they contain more glass fibers. In some special applications, heavy weight may affect the roof load, especially when the bearing capacity of the roof structure needs to be considered, it is necessary to weigh the problem that using a higher density blanket may increase the roof burden.
Low-density blankets are light, easy to transport and install, and are suitable for projects with low weight requirements, such as some lightweight roofs, residential buildings, etc.
3. Choose density according to roof requirements
When choosing the appropriate fiberglass blanket density, you need to make a decision based on the actual application scenario, roof structure and climatic conditions. The following are several common roof types and applicable fiberglass blanket density references:

(1) Industrial plant roof
Recommended density: 400g/m² - 600g/m². Industrial plants often require higher compressive strength and durability, so high-density blankets are more suitable. High-density fiberglass blankets can withstand the larger loads that may occur on the plant roof and have stronger waterproof and UV resistance.
(2) Commercial building roof
Recommended density: 300g/m² - 500g/m². Commercial building roofs usually have higher strength requirements and better waterproof performance. Moderate density can not only ensure strength and stability, but also provide more flexible construction methods.
(3) Residential roofs
Recommended density: 200g/m² - 400g/m². Residential roofs have lower load requirements and relatively lower strength requirements for fiberglass blankets, so lower density blankets can be selected. Such blankets are not only sufficient to meet waterproofing requirements, but also reduce the overall cost of the building.
(4) Extreme climate areas (such as high temperature and strong wind areas)
Recommended density: 400g/m² - 600g/m². In extreme climate conditions, the tensile strength and UV resistance of roofing materials are crucial. High-density blankets can better withstand high temperatures and strong winds, while improving the durability of the roof.