Mesh or External antenna

I need to figure out how to get a wifi signal out to a pool automation controller outdoors.  I have an R9000, X10 router onsite at the opposite side of the house.  The outdoor location can see the network but the signal is too weak to use consistently.  Are there any outdoor antenna configurations that work with the R9000 or do I need to look at some type of mesh configuration.  If the mesh is required are there netgear devices that can work in an outdoor configuration.  I could put a device in the roofing area if signal can get through roof with enough signal to be useful.

Any suggestions would be appreciated.  I will do the engineering but looking for any experience folks have to point a direction to research.