DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   Building & Construction (http://www.diychatroom.com/f19/)
-   -   Platform (second level) on deck. (http://www.diychatroom.com/f19/platform-second-level-deck-188325/)

dabeast 10-09-2013 04:20 PM

Platform (second level) on deck.
 
1 Attachment(s)
Is there a way to build up a second level on a deck without putting in more posts?

Attached is a picture of what I'm looking for. The black is the main deck and the red would be a 4 foot by 4 foot landing 1 step up from the main deck (7 inches). Green circles are the current footers/posts.

Can I just put the 4x4 landing on top of the joists and attach them with ties or do I need to put more posts in?

cortell 10-09-2013 04:37 PM

That should be fine as long as the deck design isn't tight to code. You're increasing the dead load in that area. If you don't remove the deck boards on the first layer, then you're actually doubling the dead load.

This is important only if your deck was built to bare minimum code (or below it)--i.e., the beams and joists spans barely meet the minimum values specified by code for the size of the deck. If that's the case, then you might want to consider strengthening before building it up. There are many ways to go about this, depending on what parts of the deck are weak. It may not require additional posts.

So, at this point you're asking yourself...how the hell do I know if the deck is below code, barely meets it or exceeds it? Good question:) You can measure your decks spans and compare them the AWC prescriptive code book tables. Or, you can do the poor man's assessment: jump up and down in the middle of the deck (away from perimeter and beams). Does it feel bouncy? If not, it's probably exceeding code, at least enough to take some additional dead load on part of the deck.

Now, if you were talking about adding a hot tub, that's a whole 'nother story...

joecaption 10-09-2013 04:39 PM

Not clear on what you already have.
What's there now? Is there already joist and decking there?
A real picture of what you have instead of a drawing may help picture it.
What's this platform for?

tony.g 10-09-2013 04:44 PM

Strictly it would depend on the span of the joists and the spacing of the existing posts, but in practice you will be adding < 5lbs/sq.ft at that corner so it should be fine.

dabeast 10-09-2013 04:57 PM

This is just planning now for the deck.

I'm going to be using 2x8 joists on 12'' centers. With double 2x10s for the beams. Joists will only span 8 feet.


16x8 deck. The 4x4 is the landing outside the door.

Door, 7'' down to 4x4 landing, down to deck, down 2 stairs to the ground.

cortell 10-09-2013 05:04 PM

Quote:

Originally Posted by dabeast (Post 1251573)
This is just planning now for the deck.

I'm going to be using 2x8 joists on 12'' centers. With double 2x10s for the beams. Joists will only span 8 feet.


16x8 deck. The 4x4 is the landing outside the door.

Door, 7'' down to 4x4 landing, down to deck, down 2 stairs to the ground.

Haven't checked the tables, but I believe that joist span is plenty above code. What is your beam span?

dabeast 10-09-2013 05:08 PM

Beam is 2 2x10s 16' long with a post in the middle at 8 feet.

cortell 10-09-2013 05:15 PM

Quote:

Originally Posted by dabeast (Post 1251577)
Beam is 2 2x10s 16' long with a post in the middle at 8 feet.

You're equally good there. Assuming normal loads (no hot tubs!), and that you're using SYP (I think these days all PT wood is SYP), and that you're using grade #2 or better, you're fine building that second layer without additional reinforcement.

tony.g 10-09-2013 05:17 PM

Assuming your code live load = 40psf, deck dead load = approx 10psf, the double 2x10 will be supporting around 1600lbs. maximum. Your 4x4 'mini-deck' would add no more than about 60lbs on top of that; that puts it in perspective.

dabeast 10-10-2013 02:36 PM

No hot tubs as this will be in the front yard (don't want the neighborhood seeing my naked body and making everyone jealous :laughing:).

It is all going to be pressure treated. I will probably put some extra blocking in the joists below this section also just to give it a bit more support.

AndyGump 10-11-2013 01:07 AM

If I read everything correctly about what you want to do, then 2-2x12s for the beam would be right.

Andy.


All times are GMT -5. The time now is 09:47 PM.


Copyright 2003-2014 Escalate Media LP. All Rights Reserved