Balcony leak

I have an external balcony which has Hardiboard siding. It keeps cracking at one point underneath, and letting water in. It's probably due to the balcony flexing in the wind (slightly). Any ideas for repairs? The area of cracking is about 2x2 inches.
Thanks much
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Site Timeline is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.