# Forum Home Renovation Sub Flooring  Water on concrete footings

## spurf

Hi guys, 
I have a single level, Hebel Powerpanel clad, wood framed house that is around 10 years old. It has perimeter brick foundation on concrete strip footings and brick piers on concrete footers. The sub-floor is between 30 - 50cm below the surrounding yard. The block is relatively level, with the front yard sloping towards the street around 3 meters below. The street has a south to north downwards slope and my place is relatively high up with only one neighbour higher than me with a retaining wall separating us. The retaining wall seems to have a french drain installed as there is a pipe level with the retaining wall connecting to the street that seems to discharge water a few hours after it starts raining and continues for several hours after. 
I have water accumulating on top of the concrete strip footings (up to 14cm deep!) which are around 15cm lower than the sub-floor soil which is dry. The water seems to be originating from the south east concreted path which discharges water directly onto the south west lawn which is abutting the house. The bottom of the perimeter brick foundation has gaps between them presumably to let water out but unfortunately is helping water get in! The water is difficult to drain once under the house as the surrounding land is higher than the sub-floor and the strip footings are uneven in depth so I have only been able to partially pump out the water using a submersible pump. Fortunately despite this there doesn't appear to be any major structural consequences except for 2 interior doors who's latches don't align properly and a fine crack in the ceiling. 
My plan is to excavate the lawn next to the south west and north west walls and apply a water proofing compound to the foundation. Additionally I am hoping to install a french drain along the footer of those walls and connect it to my storm water system. I also want to install a surface drain to catch the south east run-off. If water still gets in I was then planning to water proof on the inside of the foundation as I can't access the rest of the exterior without breaking a lot of concrete and moving my hot water heater. 
Does this sound like a reasonable plan of attack and what water proofing products would you guys recommend especially if I end up having to waterproof the inside of the foundation, as my understanding is many products have poor negative water pressure resistance?

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## boo

Hi mate. 
I get why few have responded so far... 
That's no easy solution, but it seems you are thinking in the right direction. I have a similar scenario that is being addressed by french drains with ag-pipe as low as possible near the base of the footings. Water-proofing is a somewhat superficial fix, and yes, doing that to the _inside_ of the wall is less effective and more prone to fail. 
You may need to consider a different method for surface and sub-surface water. 
The short answer is: get professional advice from a plumber for your specific situation, not hit 'n' miss advice like you get from a forum where any bogan (like me) can comment.

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## spurf

Thanks for the advice boo, I did get advice from 2 different plumbers but they weren't very useful and contradicted eachother  :Mad:  
I have gotten around to installing a pit to catch the south east concrete run-off which has helped keep the lawn from transforming into a swamp. Unfortunately I am still getting water on the concrete footings, illustrated today after an unseasonal downpoor which transformed the footings from dry to soaked in under 24 hours with by my calculations at least 1000L of water  :Shock:  
Given how quickly this happened I am pretty confident the water is subsoil water coming through the "weep holes" between the first row of foundation bricks as the rest of the wall is dry. The "weep holes" are between each brick, which are split half-bricks installed perpendicularly with no motar between them. Does anyone have any idea what the point of these holes are? Being installed sub-terraneanly seems pretty obvious that this problem would happen  :Confused:  
My plan is to try to fill these holes with a suitable filler as my last option is to tear up a lot of reinforced concrete to access the exterior of the foundation  :Cry:  
Does anyone know of a suitable product, preferrable injectable using a "sausage" or caulking gun that can cope with a bit of residual moisture and clay around the brick joints?

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## egoxrt

Water will always take the path of least resistance and remember the area around your footings will be much looser than the surrounding soil. The other issue you have is that the soil on the inside of the wall is lower than the outside so the water will try to level itself out. 
Gaps or no gaps the water will penetrate the mortar, maybe not as easily as your gaps, but it will still do it. I have the exact same problem here, i had a little success by water proofing the outside of the wall and using agi below the first course of bricks a couple of meters away, that was until we started getting above normal levels of rain again. 
Also, if you remove this level of moisture to rapidly you will more than likely cause more damage than good, you will unsettle the foundation,i was warned by a engineer, this is why the agi is two meters away.  
Apart from the fact that if sub soil water rises to ground level and causes moisture issues, having water on the footing on the inside, or outside is no different, it's still there. You must be on clay by the sounds of things also?  
The major problem i have had from this issue has been some bricks on the perimeter piers have been affected by spalling, but we are talking over 50 years and quite a lot of salts in the soil.The house has some minor crack in the brickwork but compared to many in my area it has fared well.  
I wish you luck in your endeavour to stop this, i spent 30k in ripping up paving and installing new plumbing, agi, etc and it has returned once again with this crazy weather we have been having, a months rain in two days wont help, clay is saturated and the water needs to go somewhere.

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## Oldsaltoz

Waterproofing the exterior wall is not a DIY job, unless you enjoy doing this sort of thin several times. Over the counter products are often a much cheaper option in the short term but many do meet any standards or tests. 
The wall can be very successfully sealed, but it will need a professional who is prepared to give you a guarantee on the product/s and workmanship. 
Also note the inner wall can also be sealed, I recently stopped leaks in brand new service pit that was just over 2.2 m deep and 25 m long, the leak was between the base slab and the walls, both were 350 mm thick (the pit was for truck repairs, not cars). 
If you would like some free professional advice use the link below. 
Good luck. :Smilie:

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## twinny

why don't you just mass fill the rest of the footing holes so that they are concrete to just over surrounding soil level? that'll fix the ponding and have no adverse structural effect on a pier. presuming your concern is water ponding in the holes that is ?  :Redface:

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## spurf

Thanks for the advice guys and sorry for the late reply, have been distracted with work. I have done some more sleuthing. I have discovered that 3/4 of my house discharges to a stormwater pipoe at the rear of my property with the rest discharging to the street. This pipe travels down 3m vertically down to get underneath the retaining wall on the north of my property. 
My new plan is to cut a strip into the south east concrete path along the length of the house. I will then excavate soil down to below the level of the footings and install ag-line and gravel and run this to the stormwater pipe to the rear of the house. For completeness I was hoping to install a reln type surface drain into the cut strip to capture any surface water and run this in a seperate pipe to the stormwater pipe. 
I have some questions: 
1. The reln drains are usually installed with fresh concrete poured around it. Is it feasible to lay it in the trench created by cutting the concrete, packing either side with sand and then sealing with a product like Compriband? The drain will at most have to cope with pedestrian traffic. 
2. I have read good things about Dimpled Membranes installed against foundation walls to overcome hydrostatic pressure. Has anyone had any experiences with these products and know of any stockists?   :Biggrin:

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## spurf

Hi Guys, 
Finally got around to sorting this out! It was two weeks of backbreaking work, cursing the original builder who could have sorted this out in a couple of hours on construction. 20 metre trench dug by hand to remove 8 cubic metres of soggy clay, 1 cubic metre of reinforced concrete and all carted by wheelbarrow. Thankfully it was all worth it, my subfloor has completely dried out! Basic steps where:  
- dig down to below footer level
- waterproof exterior foundation with Maxseal Foundation
- added platon dimpled membrane
- lined trench with geotextile
- 100mm ag line (socked as they were out of non-socked on the day) connected to stormwater
- backfill with 25mm aggregate 
Also added some surface drainage in the same trench to catch water from my concrete path and a tap. Here are some happy snaps

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