sorry to come in here, but i missed the original post.
i agree with 'newbie' on this one, and might add you need to do some visual research when it rains to take note of where this water comes from, also are you at the bottom of a slope where all water from the above properties drains to.
as far asi am aware water can be the enemy of foundations as it seeps through the cement i have been told it weakens the structure of the cement, in worst case scenerio could cause reinforcing to rust and swell causing the cement to crack.
also don't recommend having gardens or trees up against the foundations, should be app' a 2 meter buffer zone between plantings and the foudations. all toward stable moisture levels around the foundations. also considers termites.
anyhow for now take a look at our french/agricultiral drain presentation you may have to consider something like this?
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is our story on our research:
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how we determined the placement of the ag' drain we were involved in installing.
first up like i said i had done a couple or 3 or 4 years of observation, this water came travelled through our neighbours foundations and flooded our front yard in times of heavy rain and the water continued to flow through his foundations and across his underhouse storage garage area, so at the least inconvenient for him as it was not dry storage then, for some days week whatever after the rain event.
anyhow after a period and as any good neighbour might i began to sell him on the idea of an ag' drain, yes i will be bitterly honest here if he didn't do it above his house we were going to have to do it along the bottom side of his boundry in his yard to benefit us alone, there was no option to do anything in our yard. but it would hardly be worth our effort for some front yard flooding.
we got on well and he could see the issue with probable failure of cement slab and cement stumps. so i talked him through how i saw it.
he was near the bottom of this app' 6% slope. now at the top of the slope was another street that storm water went direct to the adjacent wetland, a couple houses right at teh very top app' 200 meters up and away. so that meant abut 5 houses could not gravity run their storm water to the street or storm water drain as they too were below the slope.
so as our enquiries found, the builder developer was permitted to put in a large rubble drain down the inside of teh back property lines of these affected house, this rubble drain was fed into a gravel sump (huge hole filled with gravel to allow the trapping of certain water and let it permiate into the clay sub soil) yes all soil was clay.
needless to say of course these sorts of systems provide a cheap remedy and are council apporved but have serious limitations, you see clay makes for an ideal dam, farmers can't have dams without clay soil, once clay saturates no more water will flow into or through it, why dams work so well. and later on at another suburb our next door neighbour put in a large car apron creating a catchment of which i indicated to him he could not pass that water down to us, so his builder put in such a drain system, they made it obvious they did not like ahving to do it, and yes in heavy or continued rain it all flowed out the top of the sump across our back boundry into other yards. it was like a geisher.
the best most expensive treatment would have been to seek pemission to put a pvc drain through 2 yeards (these 2 yards efected from the overflow and it would have saved another
2 from ever being affected) to the lower storm water drain, you can imagine expensive hey and ths overflow water was never going to affect him, out of sight out of mind.
anyway this drain scenerio had same/similar issues, the builder could have gotten pemission to install a pvc drain down to the wetland then there would be no problem for any others, i look carefully now at topography before we buy.
so that was a major issue in my neighbours issue, some hidden ones we found the digger guy helped here also was a disused septic tank with the top smashed in so they could fill it with dirt but they didn't punch a hole through the bottom which would have helped, the tanks should have been removed but guess the owner then was not going to fork out the cash. this was the cause of why the water continued until the level dropped in that tank.
the digger bloke pointed out that the old leach field pipes all had a downhill flow back toward the house, a bad plumber i would say, must have been issues with the owners who had it then? so we factored all that in as the job the ag' drain had to control. the old septic system actually had some uphill flow factor in it between the tank and the leach field pipes. legacy of house being built without owner supervision there is a lesson to be learnt there, with the home we built we were there each and every day even then they tried shot cuts.
we ran teh drain and connected it to a lower storm water pipe to evacuate that water away from his house, we use pvc in leiu of black flexable as the pvc can be cleaned at anytime using a plumbers eel. you can in fact make your own pvc ag' pipe by buying normal pipe then with a grinder cut slots down 2 sides.
anyhow all worked well in the above scenerio.
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