New Floor for Wooden Deck

[Pipsisiwah]

I have an old outside deck made of 2x4 wood. The wood is 25 years old and was never really kept up, although it is still structurally sound. Part of the deck is uncovered (about 150 sq ft) and another part is covered (about 250 sq ft). The entire deck is well-ventilated underneath.

My idea is to cover the existing deck with exterior grade plywood, then cover that with green plastic imitation grass material. Is this a good way to go? By using the existing 2x4 I wouldn't need 3/4-inch plywood. I thought that perhaps 5/8 or even 1/2 inch would suffice.

Are there any problems with my idea or any reasons not to do it this way?

[Hellrazor]

1-The plywood will make the decking underneath it rot faster since it can't dry out.
2- If the deck framing is made out of 2x4's too, i doubt its up to code, check into it.
3- Will the deck support the added weight of the plywood, goes back to #2, which i also doubt.
4- That green carpet stuff is ugly. But thats IMO... :eek:

[Joe.Carrick]

The Carpet would also make the plywood rot and the 2x4's beneath the plywood. This is just not a good idea.

[lefty]

EVERY 25 year old deck I have ever rebuilt has meant starting at the dirt, ignoring the existing footings, and starting from scratch. EVERYTHING from 18" below grade gets replaced.

[Pipsisiwah]

3- Will the deck support the added weight of the plywood, goes back to #2, which i also doubt.
4- That green carpet stuff is ugly. But thats IMO...

3> In So. Cal., decks around mobile homes are 3/4 TIG exterior plywood covered with the green carpet. Sooner or later they will rot I suppose, but if one should not use plywood as a base, what should one use?? (I have no idea).

4> Reminds me of the lyrics, "Saw yo' wife the other day...she sho' is ugly!"
"Yeah, but she sho' can cook!" (Make an Ugly Woman Your Wife)

I don't particularly like the green carpet stuff, but that's what the little lady seems to want. ;) I'm really not sure what to put down, myself. :confused:

[lefty]

Pipsisiwah,

Decks in CA mobile home parks have used either 3/4" T&G or 1-1/8" T&G plywood covered with plastic carpet (usually green or gray) for years mainly because they are the cheapest deck to build that the CA Dept. of Housing will approve. (Mobile homes in parks are covered by DOH, not your local bldg. dept.) Not sure who approved you deck if it was built with 2X4's -- the standard DOH plan for years has called for 4X6's at 32" O.C. if 3/4" plywood was used, or 48" O.C. if the 1-1/8" plywood was used.

Regardless of how your existing deck was built, there's nothing saying that you HAVE to use plywood and carpet. That style of deck usually lasts about 20 years in a mobile home park, because they are generally covered with a V-pan awning. Uncoved sections last about 10 years. Most MH owners replace them with a composite deck. They are tired of the look, and tired of the maintenance involved. But you HAVE to start from the ground up to do that. Your existing framing won't support a composite deck. Assuming that your pier blocks were set on proper footings (16" square and 10" deep) and at the proper spacing (6' apart, max.), and that your ROWS of pier blocks are no more than 6' apart, you can use the existing pier blocks. (If their spacing is too much, simply add another pier block or a row of pier blocks as needed.) From there, you will be starting with all new lumber.

[Pipsisiwah]

I appreciate your confirmation on 3/4" TG plywood and plastic grass covering in CA mobile home parks - means I'm not senile - yet!

I know that replacing a flush valve in a toilet can lead to replacing the valve seat, which means turning off the inlet valve, which will leak, which means replacing it, which can also mean replacing the stub out of the wall, etc. etc.

Been there, done that.

I suspected the same went for 20-year-old wooden decks, and was not happy with your (and other's) confirmation, but so be it. Thanks for your input. I'm gonna hafta rethink this through a bit.

[lefty]

Pipsisiwah,

Repairing old decks and old plumbing can end up being about the same thing, only more so with old decks!! Trying to use a 20 year old deck frame is a waste of time -- at least IMHO. At BEST, you'll 5 years, maybe 10 out of the framing, and then THAT will be falling apart. Best to just bite the bullet and replace the entire thing now. (Lumber will never be cheaper than it is today!!)

[mjdonovan]

After 25 years I would doubt the 2x4s have the structural integrity to hold much, not to mention they are probably out of code. Also putting on plywood will cause rot.

My recommenations replace the entire deck for saftey and asthetics.