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Gardening & Landscaping

Leaking Coping Joints Rendered Wall

Anonymous user 01/03/2024 - 2.55 PM

We have two retaining walls in our tiered garden. The walls have been rendered with K-Rend and they have a porcelain coping stone ontop of them ( these are just the same as we used for the paving, but cut to be coping stones ) A drip was cut on them after they were fitted. They were fitted on a mortar bed and pointed with the same. We are getting water flooding down and staining the wall, these are not just little drips but large amounts of water stains. It looks to me like the water is getting underneath the coping stones by pouring through the joints and then flooding down the wall. This is a guess, I am not experienced in this. Some of the coping stones have even come loose which I think maybe further suggests water is getting under? Any advice is appreciated? Do the joints need sealed to make sure water doesnt go through them?

Are you a tradesperson and able to answer this question?

2 Answers

Anonymous user

Hello, You have three options: 1. Either take off the copings and dress lead over the top like you do with a property wall parapet wall and bed all copings back on. You can see about 50mm of lead either side though so it might not look very nice. 2. Take off the copings and k-rend before putting them back on with a waterproof tile adesive. k-rend has silicone in it making it even more waterproof. 3. The cheapest option if you have metres of stones to replace is to bed the loose copings as best you can and grout well between stones making sure the grout reaches the continuous drip or it will get through the gap and run down the wall before it reaches the drip, and then apply a paving sealer over the stones and grout. Ps. All three options the water needs to hit the top of the stones and then travel over the stones around the stone edge and fall off the drip before it can reach the wall. The drip needs to be continuous and far enough away from the wall to work. Like a window cill. Hope this helps.

Answered16 March 2021

Anonymous user

To understand fully I'd need to know a few more things, and assuming we have soil behind the walls. 1) Are there "weep holes" in the wall? Normally short lengths of small pipe in the joints coming from front to back - they allow excess water to exit the area easily. 2) Was there any grading in the soil against the wall? I use free draining material along the base and a foot or 2 up the wall if I can. Again this acts as a free draining area, with the weep holes as well you massively reduce the pressure of water behind the wall, it can escape much quicker. I have even used a narrow French drain/soakaway system that also brings water around the side and away from the wall. I believe that if none of these things are present , or blocked etc, it's simply that when there's a lot of rain the water will not escape fast enough to avoid the pressure that appears to be forcing through the top layers of the wall. If there are any of these systems present it could be something has shifted or sunk. And that wouldn't be a criticism of any work because with large volumes of soil, water the unforseen can happen to anybody. Hope that helps, and would be happy to have a no obligation chat with customer if it helps, today (Tues) is my admin day so would be a chance of catching me! Best James, earthworks

Answered16 March 2021