How to install decking flashing?

Swaartbaard

Hi all,

First post here 🥇 thank you in advance

I’ve removed 19mm pressed concrete flooring from our outdoor area and am about to lay 140mm Merbau.

Ive noticed though that there isn’t any flashing installed. Do I need to pry up the cladding and install flashing, apply new cladding and then lay the decking? The deck is covered but Brisbane sideways rain will wet the walls

Holding thumbs that there may be a simpler solution. Not sure if I’m cut out for that sort of fix 

JacobZ

Hi @Swaartbaard,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

A flashing that starts behind the bottom weatherboard and finishes on the face of the deck's ledger board would offer the best protection, but I don't think it is worth removing the bottom weatherboard to do it unless you are comfortable doing so or willing to pay someone who is.

If you were to install something like a flashing tape over the gap, I would be concerned that if water got in behind it, it would trap water against the timber, which would cause more issues than it would if it weren't there.

If you take the time to tidy everything and then apply a good bead of silicone sealant along the full length of the gap, ensuring there are no gaps or holes, then this should offer you a decent amount of protection. 

After this, ensuring the gap doesn't fill up with leaves or anything that will hold moisture against the weatherboard is about the best you can do.

Allow me to tag @Nailbag, @Dave-1 and @AlanM52 to see what they think.

Jacob