Why are bits falling off my roof? (Pics)

[flourwatersalt]

NC in case someone recognised the pics

Not sure what this bit of the roof is called but noticed a few small pieces on the ground mid-Feb and now a much bigger piece from the other side of the house this week

Built as a small development about 15 years ago, we are not original owners. Made to look old but I don't think actually using old bricks or stones. Neighbours not seeing something similar.

In mild part of the Uk so think maybe not from frost and no damage from trees or anything that may have struck it.

Should I be worried and who to call to take a look when I can? Builder? Surveyor? Insurance co? Thnx

Looks like it could be from freeze thaw action. But without seeing the local environment, knowing the recent weather, the location and positioning of your house it’s hard to comment.

In Wiltshire in the countryside on fairly level ground - sorry if that's not what you mean - first bit is north facing, second bit is East facing. First bit was when we had all that rain and stormy weather in Feb but no frost that I can recall other than a bit of ground frost. Second bit was last week when it started to get a bit warmer.

Are the stones damaged then and letting water in which then freezes? Worried now that it will continue to erode now exposed and other bits will fall off or maybe not once frosts have passed?

Thnx