[johnny67]

Right now the original tar and gravel is on the deck and it used to have a plywood fiberglass surface over it but that was removed when it rotted. I put 1 or 2inchs of concrete over the tar and gravel years ago and its still there and in good shape but I have a leaking problem. The drainage system on the deck is a drain in all four corners.

Neighbors that have the same style house have removed the bottom plank of the railing and fiberglassed their deck with the drainage going into gutters around the perimeter. I also read about dura-dek vinyl covering.

What is the best surface to have on the deck so I won't have water leaking into the garage?

 

[Ron6519]

Adding 2" of concrete on a structure that is unsupported for a majority of it's length would not have been my solution.
What ever you do, I would remove the weight of the concrete and start from there. I would expect a good deal of rot from trapped miosture. I think the subfloor would need repair as well as a joist here and there. To go over the concrete would be a mistake.
Ron

 

[johnny67]

Ron, I will remove the concrete and replace the rotted pieces of floor.

Once I get that done I will be left with joists with a 1" thick wood floor and old tar and gravel on top, I would like to get some thing that is water proof on top of this. Here is some more pics.


this is a pic from inside the garage looking up at the floor

 

[Ron6519]

It looks like you'll need both a new roof and something you can hangout on. Most roofing material will not stand up to tables and chairs. The plywood walls also look like they are having moisture issues. The short wall by the gate has lower darkening as well as the front section I can see in the photo. The wood from the garage angle looks pretty good with just a darkening near the tracks of the garage door. But that could just be the lighting.
They do have membrane roofing that you can set a deck on. It would just depend upon the clearance you can get by the entrance door.
Whatever roof you get, make sure the drainage is done properly. It's a tricky transition going through walls and into a trough.
Ron

 

[johnny67]

Whats your opinion on going with fiberglass and opening up the bottom of the railing for water runoff.
Can I screw down 5/8" tung and groove plywood over the tar and gravel for a good surface and of course I would make sure there is a 1/4 inch slope for every linear foot??

 

[Ron6519]

I'm not really familiar with a fiberglass roof. Especially one that doubles as a patio. The issue I see, is that fiberglass would need to be treated with a resin to seal the surface and I think that resin would not be up to the task of continuous foot traffic and patio furniture.
Maybe someone else will come along with more experience with your situation.
Ron

 

[johnny67]

Ok, so I have the concrete taken off the deck, I will also be taking down the whole railing. I still have to take up the tar and gravel. I am going to take this down right to the joists. My question is since the joists have no slope (their level)for water run off what is the best way to achieve this? I want 1/4" per linear foot.

 

[Ron6519]

To minimize weight, you could rip shims and install them perpendicular to the joists. If the depth was 10 ', the one by the house would be 2 1/2". Next one would be 2 1/4". They would be installed every 16".
The question is whether you have the height by the door to get this pitch when you add up the height of all the layers you need to put down.
Ron

 

[johnny67]

thanks Ron, Yes I have the height that is not a problem. The deck will be 34' long and 12' wide, the 34' will go the length of the side of the house and the joists are 12' wide perpendicular to the house. I was told to go like you said with the shims perpendicular because it will achieve an air cross flow and prevent rotting since I will be insulating the underside for the garage ceiling. Can't I just rip 2x4's and go from 3" down to nothing along the joists and just add vent holes for every joist cavity on the fascia board to prevent rotting/trapped air.

 

[Ron6519]

thanks Ron, Yes I have the height that is not a problem. The deck will be 34' long and 12' wide, the 34' will go the length of the side of the house and the joists are 12' wide perpendicular to the house. I was told to go like you said with the shims perpendicular because it will achieve an air cross flow and prevent rotting since I will be insulating the underside for the garage ceiling. Can't I just rip 2x4's and go from 3" down to nothing along the joists and just add vent holes for every joist cavity on the fascia board to prevent rotting/trapped air.

Sure, you can do that too. You just need to make sure all are cut the same or you'll have low/high spots in the mix.
Going accross the joists will highlight any of those highs or lows so you can shim or shave, based on the situation. It's also easier to rip them on a table saw to get consistant cuts.
Ron