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Under Deck Ceiling

Rob Kress's picture

 Hello All,

Back in 2003 I had an infant and a pregnant wife and no home to live in.  Through a series of good and bad circumstances I came to be my own builder (swinging hammer, pulling romex, sweating copper builder).  I didn’t know anything about building houses.  But with some great counsel from the building department and help from skilled mentors I completed the project in a year and a half (it was long and hard).  Fine homebuilding forum and all of you here were a big part of my success as well.  A glamour shot of the finished product is attached.

I am back at the forum because I have a problem and don’t know how to fix it well.  And to be honest, I have goofed up this same thing at least once or twice already.  So this time I really want to get it right.

It’s outside and wet and I’ve come to know that I am a flunky when it comes to outside and wet.

I have a walkout basement with a first floor deck and patio underneath.  My problem is the deck and patio ceiling (under side of the deck).  The top of the deck is ipe running long ways across joists coming out from the house back wall (perpenticular to joists).  All that is great and solid (after the second try :( ).  My problem is the ceiling under (on the bottom of the joists)

When I built the deck, I put rubber sheeting between the joists to catch water and run it out to the beam (swaled and there is a gutter at the end).  That largely works but only so well and water does get through to the underside (in places).

For the ceiling, I had originally installed white oak (with the belief that the rubber would do better) running parallel to the joisting out from the house back wall.  And as you would expect, it expanded and buckled because I didn’t leave enough gap between boards.  So much so that it pushed the bottom of the joists apart and caused the handrail post above to go WAY off plumb.  This off plumb intern broke the fasteners holding the handrail by the steps.  You can imagine I felt like a baffoon builder at that point.

So I took it all down expecting to see gaps in between my 2 x 4 nailers (between joists) but I did not see any gaps.  I was expecting to get a come along and pull the joists all “back together” the their right places but now it looks like the 2 x4 nailers have expanded and done the bad deed.  Attached are a couple more pictures of things.

I need help. 

Here are the things I would like out of it:

  • I would very much like to use the 4/4 white oak but will concede that it may not be a good idea
  • I would like to run parallel to the joisting
  • I am assuming that I will never be totally dry so I’m not even going to try to be


  • No matter what material I use for the ceiling (vinyl soffit, white oak, something else) I need nailers.  What should I do there or use?
  • Should I just run perpendicular to the joisting instead (don’t really want to but man that would be easy)
  • What are my good options for material if the white oak should not be used?  Vinyl soffit, hardy board?, etc….
  • if vinyl soffit, is there some special nailer stuff I could use to run parallel to the joisting?  

Thanks in advance for any help you can offer.  The breaktime crew is awesome and helpful.  Please excuse the long post.



I'd run 1 X 4" PT strapping (post #215972, reply #1 of 2)

I'd run 1 X 4" PT strapping and use PVC beadboard as the ceiling but it won't be remotely waterproof and will have mildew stains pretty quickly from water dripping through. i'd consider roofing tin install back to front on the bottoms of the joists before the strapping and beadboard.

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.

Rob there are various (post #215972, reply #2 of 2)

Rob there are various commercial solutions to your problem. I have not tried any of them before but you may want to try a tested solution.

Check this one out: