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Hi -
I need a suggestion on whether I should install a strip drain on the left side of the house, in the side alley. The slope is adequate for water flow, but the home inspector told me when I bought the house that rainwater can pond or flow toward the house wall and then flow out. So, later I asked the plumber to install a strip drain to direct the water to the stormwater system. Weep holes are also obvious and cleaned, and there is no moisture inside the house. I am only concerned about whether I should order a premium strip drain, which is an expensive solution, in case of windy rain. Even if the strip drain is installed, water or moisture may still enter the weep holes during windy or monsoon rains. Alternatively, I could use Sikaflex to seal the gap between the concrete and the wall, leaving the weep holes open before and after applying Sikaflex. Or I could do nothing and leave it as is, since there are no signs of moisture, mold, etc., and water flows toward the side gate. I know the slope isn't ideal, but it's acceptable. I used the water hose to see where the water flows. Attached are pictures and a video for reference. I really appreciate any help you can provide.
Does anyone share the experience and guidance on that?
Welcome to the Bunnings Workshop community @Sameer. It's terrific to have you join us, and many thanks for your question about drainage.
It sounds as though you have a few possible paths forward, but the first thing to weigh up is the fact that you are not currently seeing any signs of moisture, mould or internal dampness. In many situations, if there are no symptoms, nothing urgently needs to be fixed. The slope you have described is at least allowing water to move away from the wall.
The concern I have is that the concrete is sitting right up at the base of the weep holes. That is not ideal, and in many cases it is not compliant because the weep holes should sit above a clear gap so moisture has a free point of escape. When the concrete surface is level with the lowest point of the weep holes, there is always a risk that during a heavy downpour the path will briefly hold water, the gradient will not keep up, and water will lap straight into the weep holes or be drawn into the brickwork. You may not see these events from inside because water can travel in the cavity and evaporate before it ever leaves a mark. The problem usually only shows up after prolonged or torrential rain.
Installing a strip drain is the most effective preventative measure. It gives you a guaranteed low point for the water to fall into, which helps compensate for the fact that the concrete has been poured too high. It also creates some separation between the slab surface and the brick line so the damp course is less likely to be overwhelmed. While it is an added cost, it is a sensible long-term fix and removes the risk of water reaching the weep holes during storms.
Using Sikaflex to seal the joint is not a good idea. It would bridge the tiny gap that currently exists and create a continuous surface for any water to sit against. That can encourage moisture to track into the wall rather than letting any small amount drain down the expansion joint. It also does nothing to change the fact that the concrete is still too high relative to the brickwork.
Given everything you have described, doing nothing does carry some risk during exceptional weather. Installing a strip drain is a proactive solution that helps offset the height of the concrete and reduces the likelihood of water entering the wall cavity in heavy rain. If you want to protect the home for the long term, the strip drain is the best option.
Let me tag @Nailbag to get his thoughts.
Please let me know if you have any questions.
Mitchell
Hello @Sameer
Every state has its own going hourly rate for plumbers. I suggest posting the job on Airtasker or Hipages and asking the trades people online for a quote to get the going rate for your area. In regards to positioning, I propose placing a drain such as the Everhard 3m EasyDRAIN Polymer Grate And Prejoined Channel at least 200mm from your wall. Please check with your plumber for any local rules and regulations in regards to distance. The Everhard drain should be deep enough to handle any heavy downpour.
In regards to the moving the weep holes. I propose keeping them in their original position. I'm just a bit worried that if water were to enter the brick wall there would be no way for that water to get out and you would develop a heavy infestation of mould and mildew inside your interior brick wall.
Let me call on our experienced members @Nailbag and @Dave-1 for their recommendation.
If you need further assistance, please let us know.
Eric
Hi @Sameer.,
Oops.
RE: could you please post the video link? I am unable to find it in the previous message.
How to replace a vent in a brick wall.
To remove a brick it's best to use a hammer drill and I recommend this one as a good all-rounder.
And a masonry a bit smaller than the mortar joints but long enough to drill through the width which is 110mm.
Cheers
Good Evening @Sameer
By the sound of it you are in the range of "not do anything" other then keep an eye on it. If the water flows away from the side of the house towards the fence then that solves most issues.
I was thinking of running a piece of right angle metal along the wall next to the path but fear that rain running down the wall would be directed towards the air vents.
So second thought is a piece of aluminium strip shapped like an oversized electrical conduit saddle Kinetic 32mm Galvanised BSP Pipe Saddle Clips - 10 Pack With these you silastic them against the wall and also against the expansion strip/concrete path at the base. They are for forming a little dam to stop any potential blow back from wind on the path. They wont stop airflow so no issue there. It may look a little odd but might be better to be odd then cutting up and digging a drain 
And yeah you could use those saddles if you didnt want to make up a saddle from scratch.
Dave
