William1896
New Member
Hi!
I have a block work hut built into a marshy slope. The ground was dug down to bedrock and filled back with several cubic metres of concrete. A 6" base slab for the hut (roughly 5m*3m) was then cast on top for good measure.
Unfortunately the builders didn't add any waterproofer when mixing the concrete and I now have acidic water (pH 5.5 - 6) soaking through the base of the wall on the backfilled side where water seeps out of the bog. I can't see the floor inside the hut (it's covered with Kingspan and a sump tank) but the water then drips out the other side of the hut, leaving a kind of calcite deposit - it is obviously dissolving the cement as it seeps through. I was expecting the concrete to be damp but the continuous drip-drip-drip of water passing through it makes me nervous.
I'm hoping the hut will last for many centuries and I don't want the concrete to turn into a small-scale cave system as it dissolves away. The wall was meant to have been tanked as it went up but that got put off until the weather had turned - the upper parts of the wall were given a self-adhesive bitumen membrane but the base slab was then much too wet (see photo with the drainage chippings raked back) and had to be left untreated. I have a drainage pipe buried in chippings, with a Terram fabric under the back-filling: this limits the depth of water on the uphill side but cannot keep it dry.
I have tried asking companies (Sika etc) what they would suggest but I just get passed around. Assuming I can wait for some really dry weather to dig out the back-fill, pressure wash it clean and get it all dry, the options seem to then be (a) continuing the bitumen membrane downwards, (b) EPDM or similar roof membrane, like a flat roof at ground level, (c) bituminous paint, (d) concrete floor paint, (e) cementitious or polyurethane grouts, (f) injection with a chemical damp-proofer.
I guess all would work to some extent but I don't want to be repeating the exercise at any stage in the future. Can anyone suggest a suitable product?
I have a block work hut built into a marshy slope. The ground was dug down to bedrock and filled back with several cubic metres of concrete. A 6" base slab for the hut (roughly 5m*3m) was then cast on top for good measure.
Unfortunately the builders didn't add any waterproofer when mixing the concrete and I now have acidic water (pH 5.5 - 6) soaking through the base of the wall on the backfilled side where water seeps out of the bog. I can't see the floor inside the hut (it's covered with Kingspan and a sump tank) but the water then drips out the other side of the hut, leaving a kind of calcite deposit - it is obviously dissolving the cement as it seeps through. I was expecting the concrete to be damp but the continuous drip-drip-drip of water passing through it makes me nervous.
I'm hoping the hut will last for many centuries and I don't want the concrete to turn into a small-scale cave system as it dissolves away. The wall was meant to have been tanked as it went up but that got put off until the weather had turned - the upper parts of the wall were given a self-adhesive bitumen membrane but the base slab was then much too wet (see photo with the drainage chippings raked back) and had to be left untreated. I have a drainage pipe buried in chippings, with a Terram fabric under the back-filling: this limits the depth of water on the uphill side but cannot keep it dry.
I have tried asking companies (Sika etc) what they would suggest but I just get passed around. Assuming I can wait for some really dry weather to dig out the back-fill, pressure wash it clean and get it all dry, the options seem to then be (a) continuing the bitumen membrane downwards, (b) EPDM or similar roof membrane, like a flat roof at ground level, (c) bituminous paint, (d) concrete floor paint, (e) cementitious or polyurethane grouts, (f) injection with a chemical damp-proofer.
I guess all would work to some extent but I don't want to be repeating the exercise at any stage in the future. Can anyone suggest a suitable product?