Digging up Archeology
The builders began digging the foundations a few days ago. It has been a bit stop start as we have discovered a few archeological finds.
Firstly, Owen found our sewer. Well, he found it a few days ago when pulling up the concrete, but I thought it was worth a mention here. It seems that the PVC lines were put in a bit shallow when they replaced the old stoneware lines. The result was a crunch with the excavator and a quick call to the plumber. Not real harm was done, we just had to hold on and not use the loo for a few hours while it was repaired.
While digging the foundations, we have been pulling up bits of old rubbish like glass bottles and then every so often a rubble drain filled with large river rocks. We first thought these were the discharge for the septic tank. Owen also discovered where the septic was when he shoved the scoop in and discovered a liquified mud. He was lucky that he hadn't run the excavator into it over the previous few weeks. When the tank was decommissioned they punched the cement cover slab into the hole and filled it up with rubble and dirt. However, they didn't punch a drainage hole in the bottom so the soil was saturated to the point of being a sludge.
Unfortunately the footing has to go right over the middle of the tank. Owen had to scoop the sludge out and then send Eben in to finish off the job by hand. They then cut a hole in the bottom so that a cement pillar can be put into the shale below. This pillar will hold the strip foundation up which will be formed over the hole. Once all that is done, they will backfill the hole, never to be seen again.
It's lucky that the septic was where it was and not a few feet to the south. If that had been the case, then it would have been under the foundations for the heater/fireplace which apparently would have been a much larger pain in the backside.
Anyway, after some more trenching today, Owen thinks he has solved the mystery of the rubble drains. He thinks the whole site has been backfilled by about 8 inches or so. When you look at the soil profile, there is a distinct layer at the top with an orange fleck through it. The bottom of this layer is throwing up strange "finds" of glass bottles, building rubble and other bits and pieces. Under this is a darker layer of the original soil. All this lays over a heavy clay subsoil which goes down to shale at about 1m deep. It looks like the rubble drains were put in to drain the heavy clay soil. They seem to criss cross the site at fairly regular intervals.
So the upshot - or downshot from a cost perspective, is that the pier foundations may have to go down a bit deeper to the shale layer. We wont know exactly what we have to do until Owen speaks to the engineer next week.
At least we had one "find" that wasn't bad (or costly) news. Eben found a 1950 penny so we'll have to stick that one in a frame and hang it up somewhere once the renos are done!
Firstly, Owen found our sewer. Well, he found it a few days ago when pulling up the concrete, but I thought it was worth a mention here. It seems that the PVC lines were put in a bit shallow when they replaced the old stoneware lines. The result was a crunch with the excavator and a quick call to the plumber. Not real harm was done, we just had to hold on and not use the loo for a few hours while it was repaired.
While digging the foundations, we have been pulling up bits of old rubbish like glass bottles and then every so often a rubble drain filled with large river rocks. We first thought these were the discharge for the septic tank. Owen also discovered where the septic was when he shoved the scoop in and discovered a liquified mud. He was lucky that he hadn't run the excavator into it over the previous few weeks. When the tank was decommissioned they punched the cement cover slab into the hole and filled it up with rubble and dirt. However, they didn't punch a drainage hole in the bottom so the soil was saturated to the point of being a sludge.
Unfortunately the footing has to go right over the middle of the tank. Owen had to scoop the sludge out and then send Eben in to finish off the job by hand. They then cut a hole in the bottom so that a cement pillar can be put into the shale below. This pillar will hold the strip foundation up which will be formed over the hole. Once all that is done, they will backfill the hole, never to be seen again.
It's lucky that the septic was where it was and not a few feet to the south. If that had been the case, then it would have been under the foundations for the heater/fireplace which apparently would have been a much larger pain in the backside.
Anyway, after some more trenching today, Owen thinks he has solved the mystery of the rubble drains. He thinks the whole site has been backfilled by about 8 inches or so. When you look at the soil profile, there is a distinct layer at the top with an orange fleck through it. The bottom of this layer is throwing up strange "finds" of glass bottles, building rubble and other bits and pieces. Under this is a darker layer of the original soil. All this lays over a heavy clay subsoil which goes down to shale at about 1m deep. It looks like the rubble drains were put in to drain the heavy clay soil. They seem to criss cross the site at fairly regular intervals.
So the upshot - or downshot from a cost perspective, is that the pier foundations may have to go down a bit deeper to the shale layer. We wont know exactly what we have to do until Owen speaks to the engineer next week.
At least we had one "find" that wasn't bad (or costly) news. Eben found a 1950 penny so we'll have to stick that one in a frame and hang it up somewhere once the renos are done!