How to DIY Freestanding Deck Framing

This is the 2nd post in a series on the DIY freestanding redwood decks on the Main House Fixer Upper here at One Hundred Acres Home. Check out the first post on the deck footings here. This post will show you the next step – freestanding deck framing of the small posts and the deck beams. By freestanding I mean that the deck is not attached to the house with a ledger to avoid rot that is so common at deck ledgers. Instead, the deck will be self-supported and have a 1/2 inch air gap between the deck and the house. Woohoo to no legder rot!

Back Deck Posts:

I’m replacing both the front and back decks on the Main House at the same time and in the same style. Below is a photo of the back deck footings and a rough fit-up of the small support posts.

So what is going on here? Lol yeah this might look weird. Each of those posts are cut to a custom length so that their tops are level. It may not look like it in the photo, but they are. Each footing is at a different elevation, so it was a bit tricky to cut each post. I used a reference line at the house and a long level to confirm the top of each post lined up.

How did I determine the elevation of the top of the posts? Well, let’s start from the door sill and work your way down. I want 2″ from the door sill to the top of the redwood decking to meet the building code in my area. I’m splurging a bit and using real 2x redwood decking, so that’s actually 1.5 inches thick. Below that are 2×8 joists that are actually 7.25 inches tall. From there the dropped beams at 4×8, or actually 7.25 inches tall. So in total from the door sill the top of the posts should be 2″ + 1.5″ + 7.25″ + 7.25″ = 18 inches. There you go! I marked a level line at the house for the 18″ and tracked everything else from there.

Simpson Post Base

• Embeds in wet concrete after pour and is made to install flush with the concrete surface
• Embossment in the seat of the base gives increased strength
• Stress relief holes under the base resist tearing during loading

buy on amazon

Simpson Strong Tie PBS44AZ-10 ZMAX Galvanized 12-Gauge 4×4 Standoff Post Base (10-Per Box)

Back Deck Dropped Beams:

Once the dry fit was finalized, I brushed the cut ends of the pressure-treaded 4×4 posts with copper green (in a brown color) to add even more decay resistance. You can see dripping copper green on the top of the nearest post in the photo below.

Next, I set a few nails though the post bases into each post to keep in secure and plumb. A post level tool comes in handy here. Those are Simpson PBS post bases with Zmax galvanization that are cast into each concrete footing. It’s nice that they have a 1 inch standoff to keep the wood post off the concrete to avoid rot.

IRWIN Tools Magnetic Post Level

• This level has a magnetic strip and a rubber strap for convenient hands-free installation of posts, railings, pipes, and more
• Allows you to plumb and level posts, poles, pipes, railings and more
• Molded frame is durable in all conditions

buy on amazon

IRWIN Tools Magnetic Post Level (1794482),Blue

To connect the posts to the dropped beams, I’m using Simpson BC post caps with Zmax galvanization at typical posts. The 4×8 beams only span about two bays, so there is one post where two beams ends meet. At that location, I’ll use a Simpson AC post cap because it’s wider at the beams and grabs each beam section.

Below is the freestanding back deck posts and dropped beams in place. On the very far end, I added a perpendicular 4×8 beam connected to the beam ends with Simpson HUC closed face hangers. That beam will help support stair stringers. Later on I added a beam at the near side as well.

I also added 2×6 redwood braces at the far end in the photo above since the posts are a bit taller there. I connected each end of the brace with (2)-1/4 inch diameter x 3 1/2 inch Simpson SDS screws to the posts or dropped beams. The Simpson PBS posts bases have two holes in the vertical legs that I lined up for the SDS screws when connecting on that side.

Simpson Post Base

• Embeds in wet concrete after pour and is made to install flush with the concrete surface
• Embossment in the seat of the base gives increased strength
• Stress relief holes under the base resist tearing during loading
• Made from 12 gauge steel base; 14 gauge steel strap

buy on amazon

Simpson Strong Tie PBS44AZ-10 ZMAX Galvanized 12-Gauge 4×4 Standoff Post Base (10-Per Box)

Front Deck Post and Beam Framing:

The framing process is the same for the front deck as you can see in the photos below.

The 4x beams were slightly warped so I had to cut them and connect the ends over the wood posts to adjust around the warp. That was a little annoying, but it worked out.

You can see the Simpson AC post caps at the center posts in the photo below. I use those large post caps where beams connect. Then, because I like to over-strengthen things, I added some Simpson straps across the tops of the beam ends to help keep them connected even more.

Then, I added 2×6 redwood diagonal bracing just like I used at the back deck.

Freestanding Deck Joist Framing:

Remember these are freestanding decks so they won’t have a ledger connecting at the house? Well, so how do I actually frame the joists? The photo below is worth a thousand words.

Basically, I use a 2×8 perpendicular to the joists and connect all the joists to it with two face screws. This keeps the joists spaced properly. It also keeps them all connected so that I can slide this whole system front and back, relative to the house. When ready, I can slide the hole system back towards the house, leaving that 1/2 inch gap between the deck and the siding to prevent wood rot. Once I have the joists adjusted in place, I’ll toe-nail them to the dropped beams and add blocking between them along the beam lines.

Below is a photo of the joists in place for the front deck. I still need to add blocking between the joists here. In the photo, you can tell that I’m thinking about the stair placement and how the stringers will line up – more on that in the future posts!

Below is the same joist system at the back deck. The front deck has pressure-treated joists. But by the time we got around to buying joists for the back deck, lumber prices had gone all wonky. It was cheaper to buy redwood! So we bought redwood joists for the back deck, and then brushed copper green on them for addition rot protection.

That’s my husband and me just finishing up the copper green while the sun goes down. Once it dries, I’ll push the joists closer to the house, toe-nail them to the dropped beams, and add blocking just like the front deck.

Stay tuned for the redwood decking with hidden connectors in the next post!