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Roofing

Wavy and not flushing roof tiles

WoodleyCustomer 26/08/2025 - 8.14 AM

Hi everyone, We recently had our main house pitched roof retiled with old concrete tiles, and during this process, we also replaced the underlying felt, battens, gutters, UPVC fascia, and soffits with new materials. I've noticed that some of the tiles on the pitched roof appear wavy rather than flush, and the lower part of the roof (near the gutters) seems a bit flatter compared to the steeper incline of the rest of the tiles. The roofer mentioned that as long as the tiles are seated in one or two grooves, this is acceptable and the roof is water-tight. He also recommended using CT1 sealant for any large gaps (about 1 cm wide). Is it normal for old concrete tiles to show some waviness after retiling? Could this lead to potential issues like water leaks or damage to the battens or rafters, or is some waviness generally acceptable? Additionally, he is providing a 10-year insurance-backed guarantee and a 20-year guarantee from his company. I’d appreciate any insights or experiences you might have!

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2 Answers

JDB Roofing SW Limited

Rating: 5 out of 5

Honiton

It’s good that you have the insurance backed guarantee, but you should never have to put mortar in the gaps in the tiles, no creditable roofer would ever suggest this as an option.

Answered19 August 2025

Kurt Riley Roofing

Rating: 5 out of 5

Liverpool

It's not a good sign if someone is suggesting using CT1 to fill gaps between tiles. It actually sounds awful. The waviness could be from the rafters themselves where theyve settled over time, or it could be that the roof battens are poorly installed and not at a uniform gauge, giving the image of an uneven roof surface

Answered26 August 2025