Hi bro, I have this issue whereby there is this “cold part” between the old porch and the new concrete slab extension which continues to leak even after I use the PU injection. Is there other solution?

I’m thinking of these and hope to get some feedback:
1. Add more gradient to the flat roof and put waterproofing and tile up.
2. Metal decking on concrete flat roof with sufficient insulation to insulate against noises


Thanks in advance

Upload some photos of the porch, the leak etc. Difficult to give opinion based on writing.

This drawing was drawn by a fellow forumer, I’m facing the exact same problem of Pic A. I understand the contractor should have extended based on pic B

Thanks for your help!

Doesnt matter which design, if there is a small crack, water will go through.

What you need is to prevent water from reaching the edges. Construct a cement sloping edge. Finish it with zinc sheet.

If have only 1 water discharge outlet, the water will be slow to flow away esp during heavy rain. The gradient of the slab towards the discharge hole is also important.



This post has been edited by mini orchard: Dec 13 2021, 03:31 PM