DIBLU POLYSTYRENE 200MM / PACK 100 PCS

200MM POLYSTYRENE DOWEL

A 200mm polystyrene dowel is an essential component in External Thermal Insulation Composite Systems (ETICS - External Thermal Insulation Composite Systems), used for the mechanical fixing of expanded polystyrene (EPS), extruded polystyrene (XPS) or, in specific cases, mineral wool to various substrates such as concrete, solid brick, hollow brick, BCA or other building materials. This dowel is designed to provide a stable anchorage, resistant to external forces such as wind, thermal variations or the weight of the thermal insulation system, and is optimised for insulation thicknesses thinner than those covered by 220 mm, 240 mm, 260 mm or 300 mm dowels.

Detailed description

1. Composition and materials

• Main body: Made of high quality polypropylene (PP) or polyethylene (PE), sometimes fibre-reinforced for increased mechanical strength. The plastic is chosen to prevent thermal bridging, reducing heat loss and improving the energy efficiency of the building.
• Fixing Nail: Available in galvanised steel for excellent corrosion resistance and solid anchorage or reinforced plastic for less demanding applications. Metal nails are recommended for harsh substrates or harsh environmental conditions, and heat cap models reduce heat transfer through the nail.
• Flange (rosette): The upper part of the dowel, with a standard diameter of 60-65 mm, which presses the polystyrene board against the substrate surface. The flange distributes the pressure evenly, preventing damage to the insulating material.
• Expansion zone: Located at the bottom, this zone expands into the backing material to ensure a firm hold. Some designs include multiple expansion zones, effective in porous or hollow materials such as cavity brick.

2. Dimensions and technical specifications

• Overall length: 200 mm, suitable for 6-14 cm thick polystyrene boards, taking into account the adhesive layer (5-10 mm) and any additional layers (e.g. thin existing plaster).
• Diameter: The body of the dowel is typically 10 mm in diameter, compatible with standard drill bits.
• Anchoring depth: Minimum 50 mm in the supporting material (concrete, brick, etc.), according to the pull-out strength standards. The drilled hole must be 10 mm deeper than the anchorage length for correct fixing.
• Pull-out strength: Varies according to the substrate; for example, may exceed 1 kN in concrete, but is lower in BCA or hollow brick, where specialised designs may be required.

3. Uses and applications

The 200 mm gauge is mainly used for:

• Fixing thermal insulation boards in facade systems, particularly for refurbishment or construction with thin insulation thicknesses where thermal requirements are moderate.
• Various substrates: concrete, solid brick, hollow brick, BCA, porous concrete or, in rare cases, wood/OSB (with suitable screws).
• Low-rise buildings (under 25 m according to local regulations), where 4-6 dowels per square metre are recommended, depending on the technical design.
• Plinth area: For extruded polystyrene used at the plinth, dowelling should start at least 30 cm above the ground to avoid contact with moisture.

4. Advantages

• Thermal efficiency: The plastic reduces thermal bridges, contributing to better thermal insulation.
• Mechanical resistance: Provides stability even in windy conditions or temperature variations.
• Versatility: Compatible with most substrates and insulation types.
• Quick installation: Easily installed with a rotary hammer for drilling and a hammer for hammering the nail, without complex tools.
• Durability: Resistant to corrosion (galvanised nails) and degradation caused by moisture or chemical agents.

5. Installation instructions

1. Surface preparation: The polystyrene sheets are glued with special adhesive and left to harden (24-48 hours).
2. Drilling: Use a 10 mm drill bit to create a hole through the polystyrene and a minimum of 50 mm in the substrate. The hole should be 10 mm deeper than the anchor length.
3. Inserting the dowel: Insert the body of the dowel until the flange touches the surface of the polystyrene sheet.
4. Fastening the nail: Tap the nail (metal or plastic) with a hammer or screw it in until the flange presses firmly against the plate without deforming it.
5. Covering: Cover the flanges with reinforcing mesh and layers of decorative plaster.

6. Recommendations and standards

• Number of dowels: Minimum 4-6 dowels/sq.m for buildings under 25-50 m, according to project requirements.
• Length calculation: Thickness of polystyrene + thickness of existing adhesive/plaster + minimum 50 mm for anchorage.
• Certifications: Opt for European Technical Approval (ETA) dowels to meet building standards.
• Correct installation: Avoid excessive tapping, which can damage the polystyrene board, or insufficient drilling, which reduces strength.

7. Special features of the 200 mm dowel

• It is ideal for thin insulation thicknesses (6-14 cm), common in renovations, buildings with low thermal requirements or milder climates.
• The 200 mm length allows fixing into substrates without additional thick layers (e.g. thin old plaster).
• Some models include depth markings or optimised design for fast and accurate mounting.

8. Limitations and precautions

• Brittle substrates: In very porous or weak materials (e.g. porous BCA, old brick), pullout resistance may be reduced, requiring specialised tests or dowels.
• Incorrect assembly: Too wide a hole or insufficient anchorage compromises fastening.
• Compatibility: Check that the dowel is suitable for the insulation thickness and substrate type, as shorter lengths may be insufficient for thicker layers.

9. Comparison with 220 mm, 240 mm, 260 mm and 300 mm dowels

• Length: 200 mm dowel is shorter than 220 mm (by 20 mm), 240 mm (by 40 mm), 260 mm (by 60 mm) and 300 mm (by 100 mm) and is suitable for insulation thicknesses of 6-14 cm, compared to 8-16 cm (220 mm), 10-18 cm (240 mm), 12-20 cm (260 mm) or 15-25 cm (300 mm).
• Use: Ideal for projects with very thin insulation, such as minor renovations or buildings in areas with low thermal requirements, reducing costs and installation time.
• Strength: Similar performance, subject to minimum anchorage depth (50 mm). All are versatile, but the 200 mm dowel is preferred in applications with minimal insulation.

Conclusion

The 200 mm polystyrene dowel is an efficient and economical solution for fixing thermal insulation boards in façade systems, ideal for thin insulation thicknesses (6-14 cm). With a design that minimises thermal bridging and provides mechanical strength, this dowel is perfect for minor renovations, single-family houses or buildings with low energy requirements. Choosing a certified model and following the installation instructions are crucial to ensure the durability and performance of the thermal insulation system.