Another construction question

[Reckless]

 Building a deck then going to put a sunroom on it. I am not going to use your standard decking boards. Here is one idea that was suggested. Put down 5/8 plywood, then 1" rigid foam board then another 5/8 plywood. Then the sunroom. I feel more comfortable putting down 5/8 plywood then the room. On the inside of the room 1" rigid foam on top of that 5/8 ply. Anyone have a better idea or see something wrong with either of these methods? Thanks! 

[BigAl13]

The foams gonna be soft and noisy I wouldnt do it. Are yoi trying to onsulaye it

[overbite]

Now you are getting into building <a class="inlineAdmedialink" href="#">codes[/url] check your towns, I have a deck upper deck 14.X 20 and a lower 20x48 I could of used 5/4 as the codes says but I went with 2x4- 2x6 and 2x8 staggered for the decking over
 2 X10 & 12 over kill yes but not a lot more in costs 5/4 x 6 sucks and warps and will not last as long my deck is 25 years old and solid. and with that layering think moisture, I assume its a raised deck. Have a outfit that builds sun rooms come in and give you a estimate and a material list. for the deck, then go from there   Bill
All the work in and around my house I do no contractors,

[fluke - u]

 ...nice job overbite.....

[Reckless]

 Want to get some insulation on the floor.
Besides going between the joist is there another way?

[BigAl13]

Not really  the foam isnt going to give you much r value either. It will help with draft but so will 3 mil plastic. What are you going to use for flooring? Why do you not want to insulate between the joists? Are you planing on using this room year round ?  Give me more of a description of what your looking to do and Ill be able to help you a little more.

[overbite]

I hope everyone is keeping in mind he is near the shore in Barnagate, By creating a deck it becomes a crawl space. prone to dampness and and mold. That is why I recommend he check his local Building codes, Fact any problems that arise that are against the codes. voids any and all Insurance claims, and I assume there will be Elect. Provided in this room/ And by sun room you mean it will be enclosed pron to condensation. Flooring and insulation are very important. as with the type of wood used. In all due respect to others there is a proper way to build this and avoid future problems. Bill

[BigAl13]

I know bill im a contractor, well now I am an engineer. I have been on the field for nearly15 years and my Father was a carpenter for nearly 50. So I have a strong baclround in residential building. I know about his conditions there thats why I need more of a job plan so I can help him with the correct way to complete this abiding by the codes.

[overbite]

  Al I do not doubt you knowledge or experiences with <a class="inlineAdmedialink" href="#">home[/url] improvements and editions. I was just pointing out some points to the Forum as a group, I to have many years of experience on the subject. With
 50 plus years in the trades. With people in every trade. Journeymen not self taught.  And have seen many mistakes and bad Advice and Opinions given, And you as a knowledgeable person on the subject well know there is only one right way and many wrong ways.   To cut to the chase He should have a <a class="inlineAdmedialink" href="#">contractor[/url] that does Sun Rooms come in and give a free quote and what materials he will be using. And get the town code and specs. from the foundation to the roof, that is the first step, Giving advice is a good thing but the person getting the advice can do the <a class="inlineAdmedialink" href="#">job[/url] or just wants and seeks to cut corners.  When there is a 1/2 to 3/4 Million involved things have to be done right. I do not cut corners or avoid the codes and inspections. And I am a home owner that does all my own <a class="inlineAdmedialink" href="#">work[/url], so The rules are very important when it comes to doing it right. Or why would someone have homeowners insurance when work is sub par.    Bill sorry for the rand and whats with the typing hyper's in the post lately 

[Reckless]

Thanks for all the suggestions. I do get permits for just about everything. I am not going to run heat or a/c to the room. Seasonal room or 3 season room. The deck will be 12x12. 2x8 joist on 16 " centers. It will only be 12" off the ground. I will not be able to get under it once the floor is on. Its a prefab room they do sell a floor system. That is 3" foam board  sandwiched between plywood top and bottom. They suggested to put felt or tar paper on top of the joist, 5/8 plywood,1" foam board and another 5/8 ply. I want to get this floor right before I go forward. I can't see using fiberglass between the joist cause I would never be able to get to it if it had to be replaced. Or is there another product that can be used between the joist?
Thanks Again!!   

[overbite]

    Great sounds Like a Plan. Just a thought I put a small potbelly stove in friend of mine.  its great.  PS I think he has a Bear Rug in front of it to. sorry about that. Bill