Side lights in decking

Hi All,

Not really too sure if this is the right place but was wondering if anybody could help with a small query.

I'm wanting to install lights into the side riser on my decking but the joist is behind all of them.

Would putting a 30mm hole through the joist in the places marked below be ok or would it severely weaken the joist it wouldn't be worth it?

Joists are 2x4 and hole for light is 30mm.



Thoughts appreciated.

 

All done, thanks for the advice chaps.

 

Bought a set of these

http://www.festive-lights.com/solar-lights/6-white-solar-deck-lights.html

Wicked for solar lights, really bright compared to other ones I've came accross.