Flashing your projects (without getting arrested!)

Flashing your projects (without getting arrested!)

Flashing – this is what can make or break a deck’s lifespan.  And no, I’m not talkin’ about running around in a raincoat and little else!  Flashing tape and/or metal flashing will divert water away from critical points on your deck, preserving the wood and maintaining a solid structure.
The three main areas I’ll cover here are beams, ledgers and handrail post blocking.

Beams –

If you build East of the Mississippi, chances are you use doubled or tripled  2x as your support beams.  These are just beams built up by nailing multiple 2x members together.  Any time you nail 2 pieces of wood together, you create a spot for water and debris to sit on…and eventually rot out.  I pulled a built up beam apart to find this amount of rot between the plys.

One problem is you can’t see the rot as it’s hidden between the 2x plys.  It will continue to degrade until one day, the beam fails – most likely when there’s a hefty load of people on the deck.

Solution? Run a strip of 4” wide flashing tape across the top of the doubled beam (6” wide for triples) to prevent water from seeping down between the plys.  To eliminate topside penetrations, use hurricane straps such as Simpson H1s or H2.5s to secure your joists to the beam w/o running nails through the flashing tape.
For those builders who use 4x solid beams, the use of flashing tape will prevent debris from sitting on the beam top, hastening rot.


One additional thing I do is build ‘hats’ out of metal flashing for the tops of my 6×6 support posts.  This keeps water from wicking into the exposed end grain and rotting out the tops of my posts.
One important thing to note – if you use metal flashing (aluminum) w/ ACQ pressure treated wood, you MUST put a barrier between them.  The chemicals in the ACQ pressure treated wood will eat the aluminum flashing in short order.  What I do is skin the bottom of the metal w/ flashing tape so the metal doesn’t touch the pt wood.  If you have access to MCQ treated wood, this isn’t an issue for you.

Ledgers –

Can NOT stress the critical nature of this connection ENOUGH.  95% of the deck failures you read about across the country happen because the ledger failed for one reason or another.   I will cover proper ledger connections in another blog, but for now, let’s talk flashing.

I flash ledgers in a multi-part process.
1. Install Z-flashing over top edge of cut house siding (beneath ledger board)
2. Install flashing tape over top of Z metal and up the side of the house to top line of ledger.
3. Under French and sliding glass doors, I install metal flashing and caulk to seal that area from water intrusion.  I can’t tell you how many times I’ve pulled off old ledgers to find the house wall rotted out under the French or sliding glass door!  Not a pretty sight!

4. Install ledger board.
5. Install 4” flashing tape over top edge of ledger board and up the house wall under the house wrap.

Handrail Blocking –

OK, one more thing on flashing…if you’re building a deck where the handrail posts will be top-mounted (usually in a metal post situation), you’ll want solid blocking under the handrail post location.  That way, the lag screws will have a large chunk of wood to bite into, providing a secure connection for the post.Again, you’ve got wood nailed right next to wood so… flash that sucka!


Ah, yes… the numbers!

In my neck of the country, decks can cost as little as $20 per sq. ft, and as much as several hundred dollars a ft, depending on what goes into them. (Most of our projects end up between $30 – $60 per sq. ft.) that’s a big range, isn’t it! This is where a deck design professional can assist- in helping to understand just what you expect of your new outdoor living area, and the tag-along costs.

But if you aren’t yet ready to talk to a professional just yet, take heart! There are a few things you can do on your own to get a feel for what to expect.

Glenn Mathewson suggests you think thru some of the “rooms” you would like to see included on your new deck, then measure the corresponding rooms in your house. Like your 400 sq. ft. dining area, maybe half of your 600 sq. ft. living room, and just the basics of your 500 sq. ft. kitchen? Well, you may be able to share some of the size (think of your first apartment’s kitchen/living room), but you will need some space for walkways, or “hallways” in the deck. So you may be looking at a deck that is 800 to 1,000 sq. ft. in size. It might be worth doing a little thinking and research to find out what that type of square footage is worth if it were a complete house, simply as a point of reference.

Now that you know the size, and you have some idea of what you want for features (remember, more stuff costs more), take a look at your house and neighborhood. Live in a gated community in a pricey zip code? Or maybe you live back a dirt lane at the end of an unpaved county road.

While a deck builder will most likely build whatever you want regardless of where you live, a seasoned deck designer will usually make recommendations in design and materials that reflect the area, and will complement the design and construction quality of your house. You rarely see a throw-away PT deck attached to a beautiful brick home. Your new deck will most likely cost between 5% and 30% of what your house is worth.

Again, this is all about you, and what you are looking for. Don’t let a deck builder bully you into allowing them to build a shrine to their ego- do your research and talk to professionals to find out who you are comfortable working with, just like you probably did when you bought your house!

With a basis of what you would like to accomplish, and some rough idea of what it could cost, you are ready to talk to a deck design professional to start the process of narrowing down the layout, features, materials, and options that will help define the outdoor living space you and your family will create memories with for years to come.

Setting a deck budget… And how about that design!

So you’re thinking about adding a new deck, or replacing an existing deck that has outlived it’s welcome. This is the perfect opportunity to improve not only the value of your house, but the comfort of your home.

See, here’s the thing. A deck can be a simple box,and that’s not wrong, but with a little bit of thought, it could be so much more. But this isn’t about deck design (at least this entry) it’s about budget. However, your budget will drive your design, so a few simple questions should be considered.

Whenever I meet with a new client to talk about designing a deck, we spend some time talking about how they plan to use the deck, before we get to the dollars and cents. If you don’t ever picture using the deck- it’s just simple access, or you need SOMETHING there in order to sell the house, then we will want to look at designing the simplest and most affordable deck that will safely accomplish those goals. I mean, after all, why have an 800sq. ft. Deck, if you only need a 16sq. ft. landing!?

OK, so you need more than a landing with a set of steps… This is actually something you and your family are going to use.

Again, your intended use of the new deck will drive the design, which will help to determine the project budget. Simply put, the more “rooms” of your house the deck will replicate, the more $$ you will need to allocate to the project, in order to meet your needs. Want a big outdoor dining room, with a separate sitting area, and perhaps a built-in kitchen? Then not only will we need to set aside some space, but we will need a proper budget as well.

Ah, yes… The dreaded budget. Stay tuned for some facts, figures, and numbers!