Additional accessories and advice for custom-made joints
Finishing and Flashings: Our advice and useful accessories for your roof
High-performance insulation and long-lasting roofing depend not only on the quality of the sandwich panels, but also on the care taken with the finishing details. Whether you are carrying out new construction or renovation work, roof flashings are essential to ensure the waterproofing, durability, and final aesthetic of your project.
As Isotuiles roofing experts, we have compiled a complete guide for you on the finishing pieces and sealing accessories to plan for a successful installation.
Important information regarding accessories
We do not directly supply these complementary accessories in our Isotuiles catalog. However, their use is highly recommended to ensure custom, perfectly watertight, aesthetic, and durable joints to complement our sandwich panels. You can easily find them at your usual building materials supplier.
1. Flashings and Metalwork: Securing angles and joints
1. Ridge Caps
The ridge cap is a finishing piece used on multi-pitched roofs. It is placed on the projecting angle formed by two inclined slopes that meet at an angle.
Functions:
- Covers the joint between two roof slopes.
- Protects this sensitive area against infiltration (water, dust, debris).
- Ensures a clean and harmonious visual transition.
Recommended materials:
- Lacquered steel: Colors matched to the panels for a uniform appearance.
- Zinc: More traditional finish, which develops a patina over time.
Installation:
The ridge cap is attached directly to the sandwich panels using stitching screws. A sealing strip can be added underneath to strengthen protection against the elements.
2. Valleys
Unlike the ridge cap, the valley is used in the inward-facing angles of the roof, where two inclined slopes converge inward, forming a hollow.
Functions:
- Efficiently directs rainwater towards gutters or channels.
- Prevents stagnation and eliminates the risk of leaks.
- Essential for roofs with closed angles.
Recommended materials:
- Zinc: Highly durable and resistant to corrosion.
- Aluminum: Lightweight, rust-proof, and easy to install.
Installation:
Valleys are positioned directly in the inward angle of the roof structure, underneath the sandwich panels. A sealing gasket is recommended between the valley and the panels to ensure a continuous barrier. They must be connected to your drainage system.
3. Flashings
Flashing is the key element for ensuring a seal between the roof and an adjacent wall (a typical case for an extension, a lean-to, or a veranda).
Functions:
- Hermetically seals the joint between the panel and the wall.
- Prevents infiltration at the vertical interface.
- Protects insulating materials from moisture.
Recommended materials:
- Lacquered steel / Aluminum: Lightweight, aesthetic, and rust-proof.
- Lead or Zinc: Ideal for irregular walls (exposed stone) or complex shapes, as they are easily workable.
Installation:
Flashing strips adapt to the shapes of the wall and cover the sandwich panels. For optimal waterproofing, apply a polyurethane sealant or a bituminous strip at the top of the flashing. A flashing holder or trim can be added for a perfect finish.
2. Chemical Additives: Insulation and Aesthetics
Once the roofing and metalwork are installed, some details require precise adjustments, especially to perfect the insulation around the cutouts of your Isotuiles panels.
4. Expanding Insulating Foam
This is an essential sealing product for reinforcing your roof insulation, particularly around ridges, eaves, or complex cuts.
Functions:
- Strengthens overall thermal and acoustic insulation.
- Eliminates thermal bridges, drafts, and micro-leaks.
- Ensures the continuity of the building's insulating envelope.
Materials:
- Polyurethane (PU) foam: Excellent thermal performance, rigid and durable.
- Expanding silicone: More flexible, used for areas requiring flexibility (expansion).
Application:
The foam is injected directly into the gaps between or under the panels. It expands to fill every void, then hardens. Once dry, it can be easily cut with a utility knife or sanded for a clean look.
5. Acrylic Spray Paint
Hardened expanding foam, while effective, is sensitive to UV rays and remains visually unappealing (often yellow in color). The aerosol spray is the ideal finishing solution.
Functions:
- Waterproofs the expanding foam against water and moisture.
- Effectively protects against UV rays and premature aging of the insulation.
- Harmonizes the visual appearance of the finishes with the rest of the roof.
Materials:
- Waterproof acrylic: Ensures excellent adhesion to porous foam with a smooth finish.
Application:
Shake vigorously and spray from about 20–30 cm away from the dry foam. A second crossed coat can be applied after a few minutes. It dries quickly and forms a durable shield.
Ready to realize your roofing project?
You now have a solid technical foundation to install your Isotuiles sandwich panels according to professional standards, from installation to finishing.
