I'm looking to add a wood/composite deck over an existing concrete slab that has heaved/cracked and looks unsightly. We've only owned the house for a year so I don't have the full history but we have resolved some drainage issues that I assume caused the cracked slab in the first place. Now we'd like to create a more visually appealing back patio.
Some quick info:
- Slab size = 12' x 14'
- Slab thickness = 4"
- Slab is covered by overhanging shingled roof with eaves
- Vertical clearance to sliding door threshold = ~2-1/2"
- Slab heave = 3/4" ~ 1" at the center of the slab
I've considered floating deck tiles directly on top of the slab but I'm concerned about the slab not being level enough for this, and also about how well the floating tiles will hold up over an Ontario winter.
The second option is to lay down some 2x2 joists (16" OC) and put cedar/composite decking on those. This is my preferred method but I'm not sure what the best way to support the joists is. I'm thinking of using plastic shims to level & support the joists and some steel angle brackets to secure joists to slab.
I haven't seen any information on how much unevenness can be tolerated by floating tiles, so if anyone has experience with this that would be great. Otherwise, I'm mostly looking for suggestions on how to best support the 2x2 joists that the decking will sit on.