building application & ground works

Finally after what seems like an eternity we have submitted our Building Application to Huon Valley Council. This stage of planning work took a lot longer than expected with delays from other professionals, as previously mentioned.

All the usual suspects get submitted such as site and floor plans, as well as engineering drawings of footings, subfloor, framing and bracing and then roofing specifics. As well as a bunch of stuff like energy efficiency to meet the new house ratings and a ‘Certificate of Likely Compliance’ issued by the building surveyor. This sounds like a very arbitrary piece of paper, we imagine they look at us through squinted eyes “Are you likely to comply?”

So finally we are pleased to announce that the application was successful and we now have this great wad of paperwork stamped by the council and issued with a permit number. In regards to the First Home Builders Boost deadline we’re cutting it very fine and have been digging trenches for foundations at every spare moment.

We hired the small excavator again for a couple of days to get the bulk of the work done – a strip trench along the perimeter dug with the scoop, and the auger attachment for the pier holes that dot the internal space. Additional pier holes are also placed every two metres within the perimeter trench, down to a varying depth of ‘approved base’, this means rock. This varies from 10cm to 1.4m due to the slope of the land and also natural variation in the substrate. How do you know when you’re a at rock? The auger can’t screw any further, and for those with the shovel in hand it came just below a layer of loose gravelling clay – this layer became a sign of the light at the end of the hole digging, a very welcome thing to finally hit rock after pulling what seems like endless loads of clay up from below. So while the excavator saved hours of work there is still a lot of hand digging involved. Levelling the base of the trenches, cleaning up edges and moving piles away from the immediate area to keep it level, safe and stop anything falling back in and then removing pieces that do fall in.

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Later in the trenches goes trench mesh – reinforcing steel that comes in pre-made widths, secured into a box like structure that get imbedded in the concrete. It adds strength to the thing and makes the perimeter groundwork a continuous piece – hopefully less likely to slide down the hill or move too much with the varying clay soils.

As there are a few corners and curves to deal with the trench mesh needed to be bent – any joins or corners need as overlap of at least 50cm. After a bit of head scratching as to how to easily bend the steel Steve remembered a pipe bender lying idle in the shed. This make sort work of bending some beautiful art deco corners into the rebar.

Another obstacle in the ground is the existing footings from the previous owners unfinished house. As these footings (concrete strip and piers just like ours) were never approved (rebar sticking out partially covered with concrete) it would be an expensive task to have them inspected for viability so instead we chose to work around them. The geotech engineer said to treat them like “big rocks”. Once the footing plan cam through we set about trying to position it over these existing footings with minimal overlap or interference. this proved fine for the pier holes but of course the perimeter had a few crossovers from their rectangular house to our Y shape.

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Above: Our footing plan showing trenches and pier holes.

We dug as close to them as possible before consulting the engineer as to how to proceed and thankfully we were advised to do ‘tie-ins’. This involved drilling four holes per side and inserting rebar lengths that are glued in place. These length then overlap with the rest of the trench mesh and act like a join, anchoring the two sides into one – possibly creating a sturdier home as this is all connected with old footings. Luck went out way again and were we loaned a rotary drill and epoxy glue that make easy work of drilling holes and setting the rebar. The edge of one pier  that protruded into a trench did need a bit of excavation and we learnt just how hard a massive lump of concrete it – chipping away with every power and manual tool we had we shaved it down to fit an adequate amount of steel work in.

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Above: digging around existing footings in drier times.

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Above: Drill munching through concrete like it’s butter. Sight manager looks on with interest.

We have been lucky with the weather for the most part – not too much rain apart from a bit that saw pier holes fill like a bucket. One of the (many) problems with clay its ability to hold water, great for building dams not so great for making dry trenches. Letting it soak away over the week and scooping it out we got it all looking pretty good for the engineers inspection. A few pointers for the concrete pour and we have foundations approved. High (low?) and dry.

Or so we thought. Finally the dry spell broke with rain, and snow and freezing temperatures, just before we are due to pour the concrete on Monday 26th June. Don’t put away that shovel just yet – we’ve got a couple of big days tiding up for the convoy of mixers booked in. Wish us luck!

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