In motorhomes with aluminium roofs or glass fibre reinforced plastic roofs, so-called expansion marks or expansion joints can form.
These stretch marks appear on the roof and can be found along the entire length of the roof on the left and right. The expansion joint is approx. 15 cm wide.
Stretch marks are normal and even desirable to give the material room to expand: This is because both aluminium sheets and glass fibre reinforced plastic have the property of expanding when heated and contracting when cold. To enable this process, there is this expansion joint on the roofs.
This expansion joint is structurally important to prevent damage to the vehicle and the roof. The expansion joint has no influence on the quality of the vehicle and does not constitute a defect.