Decking above or below concrete step?

[pfuller]

I'm building a deck in my courtyard which has a concrete entry step extruding into it at the level of the concrete slab the house is sitting on.

I've heard that you shouldn't have the top of the deck above the level of the floor inside to avoid water and flooding problems. I was considering having the joists level with the concrete step and running the decking timber over the concrete step concealing it below. This would mean the top of the decking timber sits above the concrete slab inside, but it is below the door frame so should let in any water if the door frame is properly seal.

What do people recommend? Should i remove the concrete step and run the top of the decking below the level of the concrete slab inside? Or should i keep the step and run the decking timber over the step?

Attached are a couple of pics to explain what i mean.

[zathras]

I'd personally get swinging with a sledge hammer, 15 minutes and the problem's gone away. It looks like it is only 75mm, and you have pretty good access under the front edge.

If there is reo, perhaps a bit more effort would be required.

[addo]

I'd wondered if it's part of the floor slab... Any clear join line visible?

Regards, Adam.

[zathras]

If that's the edge of the slab, I shudder to think how the rest is constructed.

No edge beam in sight, and by the looks of it, it is varying in thickness a fair bit.

Looks like a slapped up step to me.

[pfuller]

Thanks Ray and Adam.

There is no visible join line in the slab/step (unless its under the door frame.). So i'm assuming its part of the concrete slab. The textures of the concrete inside and on the step are pretty consistant too, so i'm pretty sure its all the same structure, which is why i'm asking this question. If i remove the step, i risk upsetting the door frame and concrete slab inside the door (especially with a sledge). I do have a kanga hammer but thats probably just as hit and miss (scuse the pun . So i'd probably prefer to keep the step there and just build over it...but dont want to cause any water problems..????..what do i do?

[Dr - 307]

What's the dimension / thickness of the door jam?

And as far as water getting in the house you can leave the 2-3mm gap between door jam and deck board like you would when laying the decking and any water will just run through the gap and down the step.

But, the question is how much room do you have to actually lay deck boards on top of the step?

[zathras]

I'd try putting a crow bar under the left end and giving it a decent tug upwards. If it moves in the slightest against the bricks, it probably isn't part of the slab.
Note that I have not said it will be easy

As I said before, the edge thickness is not consistent from your pictures, and nowhere near as thick as would be required for a slab, especially for the typical reactive soil found in the west of Melbourne. It looks very much like that black mucky clay in your pictures.

I'm thinking 450mm edge thickness, and probably 300mm across if it were a proper edge beam of a slab.
You don't have the house plans by any chance? They should show the slab dimensions...

Failing that, it is hard to believe it would be structural, perhaps a demo saw across the doorway then break it away from there?
Or if you get really keen remove 25mm or so off the top with demo saw and kanga so the boards will finish properly.

Put it this way, it would look far better without the concrete landing IMHO

[pfuller]

Thanks again Ray. Thankfully, it wasn't attached to the slab and i was able to pull it out from the wall as you described. Its all smashed up now and i'm ready to rock with the decking sub-floor. Cheers, Peter.

[zathras]

Bueady, you were probably swearing and cursing at breaking up the concrete, but once the job is complete you'll be glad you did.

You can sit back on the new deck with a coldie and admire your handy work, once you're done of course.