INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Concrete over wood @ exposed deck

Concrete over wood @ exposed deck

(OP)
Hi all!

What is everybody's detailing preference at a wood framed deck topped with concrete? The deck will be exposed to rain. I'm inclined to put a pressure treated plywood deck, waterpoofing membrane over that and then pour concrete. If the concrete is capped with a closure angle, due to concrete being porous, is there a chance of water pooling at the waterproofing membrane since it would have nowhere to drain?

The detail I'm thinking of going with is a 1 1/8" PT deck, a layer of felt paper, then topped with a concrete with integral waterproofing. Is this overkill for my situation? Please see attached detail.

RE: Concrete over wood @ exposed deck

Specify marine plywood, a PT ledger (maybe 3X considering the length of nails for the hangers, and vent the soffits with strip vents fore and aft.

Mike McCann, PE, SE (WA)


RE: Concrete over wood @ exposed deck

Looks very similar to the balcony which collapsed at Berkeley. Whatever your detail, it will never be done correctly, and it will leak, and the wood will deteriorate with time.

RE: Concrete over wood @ exposed deck

BH:

The detail is very poor - water will be trapped between the ply and concrete, and between the HSS and the ledger.

Take a look at the article at the link - Joe shows how to do it:

Link

Also, I'd be inclined to use precast pavers instead of concrete so repairs can be done with minimum fuss.

Regards,

DB

RE: Concrete over wood @ exposed deck

Def. do not use a closure angle. Form that up an inch or so past the HSS and put a cspillary break notch in the bottom.

RE: Concrete over wood @ exposed deck

Second to XR250.

You'll could get water between the steel angle and the concrete. Ditch the angle and push the concrete out a few inches beyond the HSS.
I've seen architects detail an upside-down "V" notch in the bottom of the concrete to force water to drip there.

Do you have occupied and enclosed space below?

RE: Concrete over wood @ exposed deck

suggest 1/4" per foot

RE: Concrete over wood @ exposed deck

(OP)
Thank you all for your input!

I've followed DBronson's link for detailing this situation. Concrete over wood framing stinks in general. How do you think the clients would react to specify concrete with integral waterproofing in addition to this detail (Hycrete). I have no idea how much this stuff costs. Revised detail is attached. Thanks msquared for ledger nailing depth advice.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close