decking over an existing deck
i have a home in Virginia that is in the country, the deck gets quite a bit of sunlight in the summer. I have an existing 24 ft by 22 ft deck made of what looks to be pressure treated planks. The deck is prob 18 years old and is in good shape as i have replaced the bad warped planks.
My question is instead of ripping up each plank can i lay trex perpendicular to the existing decking, transistion height is not a problem??????
i think i will do more damage to the support beams if i rip up the existing deck.
The old decking will rot rapidly where the new decking is laid across it. Depends on whether that's OK with you.
I suppose it is not much different from things that are left on a deck, such as carpeting and plant pots. I would be thinking about,
1. if your support structure is adquate for the added weight
2. if mold might grow between the planks
3. firmly screwing down old deck first
4. that trex owners say it gets really hot to bare feet and is prone to mold stain that can not be washed away
5. sandwiching construction materials is not tried and true method, and closest example may be too many layers of roofing
6. keeping in mind you don't change the railing height and stair riser heights, especially the last step
7. letting outdoor things dry out is always best
I might just lay down 3'x3' area of the trex and weigh it down with stones or bricks over maybe couple of seasons and see what happens. Having said that, ripping out old deck is not that hard. Nails are probably little loose anyway and having 4' bar makes it much easier. If removing the old deck, make sure the joists are not floppy and you have a solid footing to work on. Hope it helps.
Mold and Trex
Re: >> trex owners say it gets really hot to bare feet and is prone to mold stain that can not be washed away <<
I think Trex has addressed the mold issues in their current products. That in response to all the bad press about Trex and mold maybe 3 or 4 years ago. I'm sure warranty claims fit into the picture too.
BTW- I was in a big box store the other day and saw samples where Trex has come out with a new product that looked to be made of the same stuff only it had kind of a plastic sheath - or wear layer on the top and sides - 3 sides. The layer was maybe an eighth thick. It looked nice, but the salesmen told me it was more expensive then the traditional Trex product. Doesn't sound like a very smart move to me - IMO that has always been the problem with composite decking - can't sell it to customers because it is too expensive. So now they come out with a more expensive product?
FWIW, there used to be a plastic decking made precisely for this duty -- similar to regular plastic composite decking only maybe 1/2" thick. But haven't seen it around for a couple of years.
Definitely don't do it.
Trapped water will lead to early demise of both layers, and meanwhile the whole deck can end up stinking while gunk molds away there on hot steamy days.
Trx requires 18" free air circulation under it to honor their warantee, as do most composite deck materials.
decking over deck
thanks for the responses all were good
sort of what i though in terms of mold and rot. will end up ripping up the old deck seems to be best....i dont like short cuts
Ur not gonna like this...
but when you said "will end up ripping up the old deck seems to be best" I assume you mean remove the wooden decking boards and install the Trex on the existing joists. I think this is a bad plan as you will be installing a 30 or 40 year decking product over joists that have 5 or 10 years of life left in them. Especially once you pull all those existing decking nails and leave the existing joists pocked with water pockets that will accelerate rot.
If you really want to do that, at least protect the top of the joists with some kind of rubber like membrane - like for example Vycor, that sits on top and wraps down the joists sides an inch or so.
Your first step would be to inspect the existing joists very closely to find out if there is some existing rot - poke them with a screwdriver to look for soft spots, particular near the top edge.
BTW - I also agree with the others that sandwiching decking materials will promote moisture damage and rot, etc.
i think you make a good point about the joists no sense putting in trex to last for 20 years on top of joists that will go in five.
so i agree with the conclusion that decking on decking will promote rot and mold, so now my other question is part of my deck is covered by a porch area, like a sun room with a room. I was going to enclose this area and make a breakfast nook. Since it is covered do you all think i can lay a sub floor over the the existing deck to start my addition project. The joists are open to a porch underneath.
Are there many fiberglass decks in your area? Put down ply over existing decking then FG. Good for 50 years if done right.
Got a pic or link or something? I don't think I've seen one of those before.
Here you go... My FIL and
Here you go...
My FIL and I did it ourselves. He's a salty old retired shipwright with lots of FG experience. This kind of deck is a bit of work, but lasts almost forever. He laid his deck over 50 years ago, and has done nothing to it other than twice roughing it up with a sander and rolling a fresh layer of gelcoat. Gelcoat comes in any color, but we opted for the standard "marine gray" which is cheap and effective, plus it matches our roof.
FHB mag did an article on FG decks a few years ago.
In my FIL's opinion, the biggest mistake people tend to make is mixing the resin/catalyst too "hot" (too much catalyst). He posits that polyester resin + catalyst is similar to concrete in that the chemical hardening process never stops. If you add too much catalyst the product turns brittle early which causes cracking and flaking.
Other than this it's pretty simple. First you fill all imperfections in the ply base with bondo; sand smooth. Lay down beveled 3/4" ply strips around perimeter (we also prepped the supporting posts when the house was framed). Then we cut mat, layed it out, and rolled it with resin. We went about 4" up the walls to make sure that deck water wouldn't affect the house. (It shouldn't anyway because of deck slope, but we wanted to be sure).
It was hot that summer, so he used to bang on the door at 4:30 am of the trailer we were living in, "Scott!!!! It's time to get to work!!! Get UP before it gets too hot!"
....Like I say... a salty ol' dawg....
Wondering why no railings? It's a work in progress...first comes siding (see pic 4).
Never seen anything like it. I see it has a "curb" around it. Does it hold water? Or is it "self bailing"? :-)
I knew you would ask about that.
It drains. Here's how he does it:
He takes old burnt-out fluorescent light bulb tubes and coats them with FG. When hardened, he smashes them against something which busts the glass tube inside and leaves a perfect drain tube.
He dumps some water on the deck to see where the low spot is and bores a hole through. Feather some mat around the hole, insert the tube from below and roll resin to seal the joint.
The result is a "bathtub" deck that drains well and is somewhat self-cleaning.
Seems like I can't edit my original post anymore, why???
Anyway, I wanted to add to the paragraph that starts with "Other than that...."
We rolled a layer of gray gelcoat, let it set, roughed it up with a sander, and rolled another coat.
Like I say, a bit of work, but hopefully 50+ years of weatherproof surface. An added bonus: It provides 900 sq. ft. of sheltered storage underneath.
Once someone else has commented on you post you can't edit it.
Durn database record locking... I run into this at work all the time....
I get that sometimes.....
(unable to edit) I thought maybe it was a time limit or something, but I just edited one of my old posts, so that isn't it.
Re the fiberglass deck, what is the purpose of the edge curb?
>>>Re the fiberglass deck,
>>>Re the fiberglass deck, what is the purpose of the edge curb?
It's to form a bathtub to trap the water and direct it to where you want it to go, rather than running off the edge, which can eventually hurt the rim joist.
Certainly if the deck is covered (even if not even screened in) it changes the equation substantially. Even if rainwater blows in occasionally the structure usually (except perhaps in the Pac NW) has a chance to dry out between episodes and so the pace of rot is slowed considerably, if not prevented entirely.
You do need to worry about the edges, which may be more exposed to the weather.
The answer is yes
>> I was going to enclose this area and make a breakfast nook. Since it is covered do you all think i can lay a sub floor over the the existing deck to start my addition project. << Yes, provided the deck substructure will suport conditioned space - there are different requirements for decks and rooms.
the anser is yes
yes i looked at the support structure the walls are cinderblock that support the joists and i do not expect to put anything above one floor. I though it being covered it would be ok
Joist spacing with Tres
Remember that spacing for 2 by PT pine decking is greater than that recommended for Trex particularly if laid on the bias.