Lachstock,
Looking at the second photo of the damage the opened crack
looks like it has been broken for awhile and lifting there has been the straw that broke the camels back
Your mods will be a big help ...(just my 2bobs worth)......
To add photos to a post have a look at the attached pic
The little rectangle next to the smiley face is the icon to add pics click on that and see how you go you may have to resize the pic that can be done with a bit of fiddling around with the pic