Way important. Do it right the first time and you save some big bucks in only a few years or less. In the picture, you see here is just a tin flashing. With the new codes, we have to use copper flashing because of the metals used in the new pressure-treated lumber. If you notice any white spots on the wood, no it’s not mold, it’s the copper coming out of the wood and is very normal and will wash away…
You would think that if you don’t use flashing what could go wrong? Well, I can’t even begin to tell you just how many jobs I get called on that have no flashing or was installed wrong and the problems that it caused. There was one that the deck was only two years old on a house that was three years old. Well about 20k later the homeowners didn’t need to worry anymore. What happened was the so-called deck builder never used any flashing and the rainwater found it’s the way in the house. It wasn’t enough to be visible in the house until they noticed a leak on their basement ceiling and called a plumber to fix it. Well, the plumber couldn’t fix that leak. The long story here is that the water rooted out the main ring joist and three feet of the floor joist of the house. Needless to say, I had to lift the house up and cut out all the bad wood, remove the deck and rebuild it. All because of a $40 piece of flashing. Yes, copper flashing is not cheap, but what a saving.
Now more on how to install the flashing
Sometimes a picture is worth a thousand words.
Ok, let’s get more with the times, shall we?
The flashing used today is really not as shown above. I mean copper is good and all. But mostly we use a peel and stick membrane. It’s so much better and easier to use. Well, least I think so.
Here’s a link to Amazon for some of the flashing. Link https://amzn.to/37WFCs7
You may also like to see this. The rim joist was rotted right out Deck Tension Ties For Your Deck