I am planning to lay a blue stone tiled terrace at the back of my house that needs to run in a slope away from 2 joining walls. The diagram might explain this better.enter image description here

How can I mark out this sloping gradient so they terrace slopes away from both walls. Also what is a recommended gradient for such a terrace to ensure rain runs off?


A quick check says a slope of 1/4" to 5/8" per foot.

So over a 8' wall length, that's an elevation drop of 2-5 inches.

But, you need it to slope away from both walls. (Dual pitch) That means that you'll need to go another 2-5" deeper for the free corner. You could get away with the 2" drop along both walls, making it 4" deep at the corner.

OR, You seem to want the water to flow off to the left. I'd go with one course of tiles on the left hand wall, carefully graded at the maximum slope (5/8" / ft) to keep water away from that wall, and then do a single pitch away from the other wall. (Say 3/8"). If you lay it carefully, you won't notice the difference in pitches.

  • Thanks for the answer Chris, yeah the second suggestion seems the best,fantastic . Just for convenience for reference: slope of 0.64 to 1.59cm per 30cm so over 2.44m wall is elevation drop of 5 to 12.7cm. – Gurnard Jul 17 '13 at 14:25
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    Or for even more convenience 1/4 in 12 is 21mm/m and 5/8 is 52 mm/m I'm sure you could pick any convenient value between 20 and 50 and be fine. – Chris Cudmore Jul 25 '13 at 14:19

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