Hot Topics: Deck Construction Advice

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Original Posts: Early Stage Deck Construction

fish02906 - Member

Thanks in advance to everyone willing to educate me on this!

I'm planning to build a raised "fort" for my two boys (ages four and seven), and I've come up with the design shown in the attached photos. It's basically an ~8x12 deck (made of 2x6's) on 6 4x4 posts, with a 3-sided structure on top (all 2x4's; 2x6 rafters; 2x8 ridge). There's more to come in terms of the design (e.g. windows, rails), but I thought I'd start asking for advice early on.

I'm especially interested in feedback on the post-beam, rafter-plate, and rafter-ridge connections. For the post-beam connection, I've figured a notch at the top of each post with 2 heavy gauge carriage bolts. For the rafter connections, I found some Simpson Strong Tie products that seem to be right for the job.

Any and all advice is welcome, and thanks again.

deck construction diagram computer drawing designdeck construction diagram computer drawing design

deck construction diagram computer drawing design

deck construction diagram computer drawing design

XSleeper - Group Moderator

Nice drawings! Just a few thoughts at first glance...

The post connections sound fine, assuming you use two HDG 1/2" bolts w/washers per connection.

You might find that the deck structure sways without corner gussets. (See DCA6 figure 10) You can will likely need to add blocking for these gussets to bolt to. (1/2" lags w/washers are permissible here).

Your H1 connectors should be on the outside of the building.

If your wall sheathing will not extend from top plate to bottom of deck rim, you might want to put a few strap ties down several wall studs (at least 4' on center) to tie the wall structure to the rim of the deck, to help resist uplift.

You typically want a double top plate on load bearing walls, your sheathing needs it for shear nailing.

I would probably use LSU26 hangers for the rafters at the ridge.

And I dont know if you didnt draw them, but you will need at least some rafter ties (ceiling joists) to help keep the walls together. Without them, the rafters have no triangular support and the walls can spread as the ridge sags.

And with one end being open I would suggest maybe some collar ties to resist uplift. The wind is quite powerful and you may notice that on a structure that is open on one side.

I don't know if you were thinking the ridge would be structural or not... (You dont need rafter ties if the ridge is structural) but yours will not be if the ends of the ridge are not supported. What I'm getting at is that your hangers are there for uplift and don't eliminate the need for rafter ties.

I know it's just a playhouse, but I think of building things like that to the same standards as a house, and hopefully you do too. It's the same liability even if it's a playhouse.

Marq1 - Member

I'd look into some pre made trusses, get standard size and they are very cheap. By the time you add up all those ties your probably half way there and the build time will be a fraction!

Pilot Dane - Group Moderator

I would also check your local zoning ordinances especially if you are within city limits or a smaller rural plot. A structure that size might be viewed as a deck or storage shed so you might have to comply with setback requirements.

fish02906 - Thread Starter

Marq1 - never even occurred to me! Thanks for the suggestion! I'll definitely be looking into that today.

"I'd look into some pre-made trusses, get standard size and they are very cheap. By the time you add up all those ties your probably half way there and the build time will be a fraction!"

fish02906 - Thread Starter

XSleeper - thanks so much for the comprehensive feedback! Perfect illustration of why I use this forum! I'm reviewing your input and will update the drawings. Please come back when I post them!

As a side note - using Google SketchUp to produce those drawings. On a scale of 1 to 5, I would consider myself a level 3 user of that program, and i recommend it to everyone.

"Nice drawings! Just a few thoughts at first glance..."

fish02906 - Thread Starter

XSleeper - responding to your feedback, and posting updated screen shots for support:

"The post connections sound fine, assuming you use two HDG 1/2" bolts w/washers per connection."

Confirmed.

"You might find that the deck structure sways without corner gussets."

I moved the corner posts in by 1.5 inches in order to make room for the gussets that i added to the drawing, made out of 2x6 and fastened with 1/2" lags to the post and to the "rim joist" (what do you call the joists on the very end?). Is it sufficient to have gussets arranged in just one direction? Or do i have to go both ways?

"Your H1 connectors should be on the outside of the building."

Moved them to the outside, but how do you address these metal pieces getting in the way of the plywood sheathing? I also added another layer of 2x4s at the top of the walls.

"If your wall sheathing will not extend from top plate to bottom of deck rim, you might want to put a few strap ties down several wall studs."

I moved the 4x8 plywood down by the 5.5 inches in order to overlap the deck rim.

"I would probably use LSU26 hangers...you will need at least some rafter ties...I would suggest maybe some collar ties to resist uplift."

Changed to the LSU26; thanks for the tip. I added four sets of 8' rafter ties and 4' collar ties (made out of 2x4's). I presume 1/2" lags are ok to use here, too. Sufficient?

I called the local lumber yard and unfortunately they don't stock pre-made trusses, nor were they able to recommend anyone in the area who does. One of the biggest head-scratchers for me with this project is how to erect the roof system. I usually work along, though I recognize i'll probably need an extra set of hands for this one. Even then, seems tricky. I suppose that's because i've never done this before.

deck construction diagram computer drawing design

deck construction diagram computer drawing design

deck construction diagram computer drawing design

deck construction diagram computer drawing design

deck construction diagram computer drawing design

fish02906 - Thread Starter

I have a feeling I didn't get the gusset situation quite right...

fish02906 - Thread Starter

Gussets both ways. The new one in the back (underneath where the top structure is going to go) will get in the way of the plywood sheathing as currently drawn. Maybe the solution is to add a piece of plywood between the post and the bottom of the gusset, so that the top of the gusset sits flush on top of the sheathing...?

deck construction diagram computer drawing design

XSleeper - Group Moderator

If you don't want the gusset on the outside of the post, put it on the inside of the post, and add blocking between the joists for it to lag onto.

Did I mention earlier the posts need to be 6x6?

Just three rafter ties would be sufficient, one on each end and one or two in the middle. Or maybe just do half of the building if you want a little loft area for toys and such.

Your collar ties could be directly below the ridge as high as possible. Fastening the collar and rafter ties with framing nails or construction screws (if permitted) is sufficient.

Marq1 - Member

"I called the local lumber yard and unfortunately they don't stock pre-made trusses."

Chances are slim they will be in stock, but common sizes can be ordered, I got mine at Menards, around $43 each.

fish02906 - Thread Starter

"Did I mention earlier the posts need to be 6x6?"

No you hadn't mentioned that! What's the threshold for using 4x4s?? I thought for something this small it wouldn't be a problem...?

fish02906 - Thread Starter

"I got mine at Menards, around $43 each."

Yeah that price is ridiculous! I may expand my search, though XSleeper's idea about "loft space" has given me all kinds of ideas of my own....

fish02906 - Thread Starter

Quick question—is it necessary for the rafters to be 16" OC? Can I go 24"?

Marq1 - Member

Trusses are 24", stick build, not sure!

XSleeper - Group Moderator

2012 IRC. All support posts must be 6x6. When you notch a 6x6 for a beam you will still have 2 1/2" of post to bolt into. Which reminds me... Noticed your under deck drawings... You need to double your rim for your joists to hang on. Yes you can go 24" on center if you want.

fish02906 - Thread Starter

An update for all my fans...

backyard deck construction project

backyard deck project with firepit and chairs

backyard double layer deck project

XSleeper - Group Moderator

Nice job, looks like a great place to hang out!