Grounding of the antenna is an important thing to do.It prevents the loss of our dear equipment and other non desired effects .So how to do it properly and when the grounding is needed?The rule of thumb is ,antenna being outside to start with.Indoor antenna does not need grounding,nor the one that is being deployed in the loft.The house itself provide sufficient shielding from static discharges.Outside antenna should be always mounted on metallic pole for pernament installation.The other rule of thumb for outside mounting is,if antenna does not protrude roof more than 1m ,the static protection is sufficient by pole attached to the other metallic structures,as roof and common rail and/or other antenna systems nearby.If the antenna is being placed higher over the roof over the 1m ,then sufficient gounding should be the concern.Speaking of course,is high current wire of high diameter,at least 4mm squared yellow/green color should be connected to the antennas metalic structure ,i.e holder,using a twist around the screw or properly designed soldered lug on the end of the wire,and lenght of the wire should be attached to the 1,5m long zinc grounding pole that can be bought locally in a good electical store,with bracket that is allowing wire to be connected to the pole.Hammer down the pole into the soil next to the house,connect the wire and the grounding should be sufficiant.Of course,one may argue that this grounding may require technician to measure the ground resistance to be within the limits but hey,that cost time,plenty of money and other resources.To be on a safe side,doing so is enought and certainly better that ingore the risk of static or nearby discharge and doing nothing.
Connecting antenna to the common grounding rail already on the roof is also an option,even not perfect.Antenna should have its own system.Given that antenna is on the roof,connected to the metallic structures by default ,it is hard to insulate from metal already present .
In case of a direct hit by the lightning,unfortunatelly there is not much you can do.Such a strike is very very rare and usually the equipment take the toll and does not survive.But we do all we can in a given moment enjoying a wonderful hobby of ours.