Expert: Paul S. Brown, AIA - 5/9/2008

Question
We have an upper deck above a screened in porch. We put in an under deck roof. We have a lab that also has access to the upper deck. His fur, leaves, just general outdoor elements would drop down through the upper decking to the under deck roofing. It was a mess and impossible to clean unless the roofing was taken down. After several years of trying to effectively clean the under deck roofing, I just took it down. Now all of the same junk falls on the screened in porch below. With that and weather, rain etc. we are effectively losing the use of our porch. My husband just wants to put plywood on the upper deck, and just put some type of flooring over the plywood. Hopefully fairly inexpensive, since we spent a good amount on the under deck roofing. There has to be an answer to this. What do you suggest?

Answer
Hi Peggy:
Well, I hope you won't hold it against me, but there really is no easy and good solution to this problem.  There are easy solutions, and there are good solutions, but none that are both easy and good at the same time.  This is a classic homeowner challenge ... the idea of putting the 'wasted' space beneath a deck to good use as liveable space.  A very understandable desire, but very difficult to achieve in a manner that is satisfactory; for exactly all of the reasons that you have described in your email.  Roofs and decks are very different things with very different purposes, and water is very sneaky and gets in everywhere, and so it is difficult to combine a roof and a deck in an elegant and successful manner.
The best advice I can give you is to consult with an Architect in your area; invite them out to your home, show them the problem and what you want to achieve, and then get a ballpark idea from them regarding the work involved and the cost.
Should your husband just deck it over solid?  This solution falls into the 'easy' category; but not the 'good' category.  Yes, it can be done and it will last for a while if you use appropriate weather-proof plywood and rot-resistant and/or painted wood decking.  But, eventually, the water will get in and both rot and freeze-thaw will cause deterioration, and you will wind up replacing it.
My extended family owns a lake-front house in NY state.  It was built with painted solid-floor decks outside.  We like the look, and don't want spaced boards, so .... we simply wind up replacing the decks every 10 or 15 years; and these decks are under full cover from roofs above.
Sorry that I could not be more encouraging ... this is a difficult problem to solve; not impossible, but probably expensive to do it right, and you should seek professional local expert advice for your specific installation.
Good luck!
PB