Bone Bruise

I have just came back from the doctor and I have a bone bruise that will take 3-6 weeks to heal. :( The only thing he could do is recommend that I be careful - which is my middle name - sigh. At least I got bulked billed.

Shoring Calculations

For simple cantilever shoring, the pressure can be calculated by the following formula:

max pressure = 0.8 * (1-sin(soil friction angle))/(1+sin(soil friction angle)) * soil density * height

I'm going to use 60 degrees as the soil friction angle - mostly because of the clay sand and the 'weak' sandstone seam. Only the top foot or so is really sand. Assuming a very conservative soil density of 2kg per litre, the pressure would be around 200kg per square metre. The wooden posts are certainly strong enough for that and the ply wood should be able to handle that burst pressure.

Tree Roots

I took today off - last day in a 4 day stint. I was planing on using today and yesterday for shoring - but that was finished on Saturday. The excavator guys were around again and spent the whole day here. Jim had to go off and do something in the morning so I got Glen to dig out some tree roots - from the 12m pine that was cut down. It was such a struggle that I had to help him with my reciprocal saw and cut some of the roots. Some of the roots had formed a tightly meshed web and this made it even more difficult.

Jim offered to take the roots to the tip for me - he estimated that there were 2 tons of roots. Initially I accepted saying that they were far to big for me. However I reneged and fortunately Glen latter offered to load my ute with the excavator. On the first trip, the Kimbriki guy said that the roots are classified as stumps - expensive, but I said that they were not very thick and that I loaded them myself - which was true - the first load was mostly small stuff. The second trip the guy kept on saying that I should be on the weigh bridge - about three times but not quite condemning me. I said I had another trip and then I would go on the weigh bridge - he was happy with that. That trip I carefully hid a big piece at the bottom ~200kg. I managed to unload it no problem.

The last trip was such a laugh since mostly it was that last huge root mass that stuck out of the ute by about a metre - there was no way anyone was going to let me through for free. Jim wished me luck and asked me whether I wanted a chain to tie the root to something stationary and drive off. He also hoped that there was a friendly excavator guy there to give me a hand. When Glen was placing into the back of the ute - he pushed it around and it was quite funny to see my ute also being pushed forward as well. I was pretty nervous about taking the root myself - what happens if I can't unload it???

I went the the weigh bridge and then off to the dumping area. Fortunately all the attendants were busy in conference. One guy noticed me and asked me if I just wanted a ticket. He gave me one just for veg without even looking at my ute. I struggled a bit to heave the root mass off - inching it along. Eventually I got it over the side and it was resting against the side of the ute. The only was I could tip it over was to use my feet with my hands handing onto the side of the ute with my bum on the tray. They are sure going to love me when they try to mulch this sucker. It would have been almost 4m long 80cm wide and around 40 cm thick. It certainly looked massive. But being pine it was actually quite "light". Off back to the exit weigh bridge to pay. My load weighed 550kg - I estimate the root mass would have been about 400kg of that.

Now I can move the water meter again and put in a request to council to modify the driveway on the verge.

Shoring

I spent today finishing off the shoring. I used my hardwood posts that I salvaged from the demolition. I also used ply wood to try to keep the actual soil together. The posts are generally buried 1 metre below the level of the trench. Jim, the other excavation guy loaded up the truck and took more dirt away. Glen seems better with the excavator. I'm going to try to get him to carve out the actual footings.





Yesterday and today I got the excavator to push and in some cases hammer in the posts. Interestingly a single post had no problem supporting the 5 ton excavator with it resting on its back tracks.

The shoring gives a good idea of the size of the garage - fairly big :)



3mm of rain fell last night and I felt compelled to visit the site to check out the shoring - it seems to be fine :)

The Excavation Begins

Today turned out better than expected. I was dreading many things going wrong - but they didn't. Things didn't go perfectly - the auger was missing a tooth so the hole was a bit too small for the pier liners.

The guys turned up just before 7am and dutifully waited for the council approved kick off time before starting up the machine.

The guy (Glen) drilled the holes. Before hand I explained about the geology - a weak sandstone seam running about 600mm deep. He gave a knowing nod when he hit it. The 450mm holes were a bit of a problem. Because the auger was missing a tooth, we spent a lot of time reaming them out to fit the liners - we resorted to pushing them down with the excavator with mixed success.




The next stage was the trench. The guy was very careful and did a really good job. I used a laser level to maintain accuracy. He seemed to be able to get it done to the centimeter accuracy.



It was a bit tricky with the west end the trench - Glen had to stradle the two sides of the trench with mixed success. Eventually we resorted to using a few of my salvaged timbers to reduce the pressure on the ground. It still caved in a little bit, but I was happy with the result.



Glen was very dubious about what I was planing, he kept on asking questions like whether I was planing on going into the trench and telling me that he hoped it would not rain soon. However, once I hand auger my first hole and poped a post in, he came over saying that he had to see this and went back to the excavator saying that he was very impressed.

It was about lunch time when they finished so I took up the offer of getting some of the dirt taken away.

Ready for the Excavator

I continued to use the dingo this morning to stockpile fill. I probably didn't stockpile enough, but I think I'm meant to use course gravel (for drainage) anyway. You can just make out the plywood sides I used to contain the pile in the picture. They are supported by hardwood posts buried around a metre deep or so. They seem to work well. However, the plywood bows a bit.

The only problem that I have with the Dingo is that it easily get bogged and with a bucket full of sand, it gets top heavy and has a tendency to fall over forward - the tip of the day is to hang on! Getting it unbogged is a sinch since one can just lower the bucket down and the front wheels are off the ground. If I hire one again (I doubt it), I'll make sure it is a hydraulic 4wd model - not chain! It fits easily onto the back of a aluminum tray ute using a pair of bobcat ramps. After about 8 hours of use, I think I can be considered 'OK' at handling the Dingo. I think I'll try something bigger next.

The skip bin guy picked up the 10cum of soil and dragged it away - not problem. Fortunately, the concrete drive did not crack



It is interesting that I attrack the interest of mums with their young boys. I hope the mums know what I am doing 'cause I'm sure I don't ;)

Dingo

I hired a mini excavator (called a Dingo) today to fill up the bin. It weighs around 900kg so I put it in the back of my truck :) The rental guy was a bit dubious but the the ute is rated to carry 1.4 ton pay load. The ute sure did plunge putting it on and taking it off. After around 4 hours, I can definitely say I am getting better at it. I think I prefer a shovel and wheel barrow though - I don't get bogged. I topple over once and slightly injured myself - I have a huge bruise on my shin.

I started laying out the building today. My datum point is the south west corner. I marked exactly where the piers should be placed.

You won't believe this, but the engineer had called for 600mm diameter 1.8m deep piers to support the roof covered deck. I calculated the rated performance of the pier and it can support 4000 kN and resist 350kN lateral load. It is interesting to note that the post holders are rated at 25kN compression and 45kN tension. Not that I have a problem with over designed foundations, but it is ugly. I rang the engineer ans asked whether it was really necessary for such wide diameter piers. Apparently not - he had designed to to support a two story concrete slab building and told me I can reduce it to 450mm like all of the others.

Preparing for the big excavation

I spent the last couple of days preparing for the big initial excavation. This included digging a shallow trench to indicate where the excavator should go. I got a huge skip bin delivered (10cum) which I have been filling up with soil. I'm thinking about hiring one of those dingos mini-excavators to help me out.

Plywood delivery

Graham ordered some plywood for shoring and formwork, and it was delivered today so I had to go and take delivery. The truck arrived and I opened the gate ― only to find a whole lot of pier liners (metal tubes) in the driveway. Graham hadn't expected them to be delivered till next week. So the timber man said he'd just back up to the gate and use his crane to lift the plywood over the fence. So he did. Buzz buzz (rather loud) and it was done. He did knock a small branch off the tree.


Then I went over to Council and picked up the approved Construction Certificate. It took a little longer than I'd expected (having paid all fees and filled in all forms last week) but now it's in our hot little hands.

Ready Set Go!

I spoke to the assessing officer the other day and fortunately there is no initial site inspection anymore - yay! The first inspection is excavation/steel or just before the concrete pour. I'm pretty happy about that since it has saved me a $275 inspection fee, a day off work and probably a week delay.

Liz goes in tomorrow to collect the construction certificate and I officially start on Monday or Friday for insurance purposes.

Probably the most difficult / non standard thing I am doing is a bulk excavation down to a max of 1.8m. It is sand so I have to do some shoring. I've done research and I can safely say that most builders won't do it and it can be expensive. Fortunately I have saved many timbers from the roof and floor. I plan on using those, together with plywood, to shore up the excavation. The first step is to dig a trench border to the excavation. Next I will be drilling, using a hand auger, holes 1 -1.5m deep at the bottom of the trench for many posts. Then I will lower plywood sheets between the posts and the soil. I'll be putting holes in the plywood to reduce the hydro static pressure. From my calcs, it should all be ok. I'll be spending around 2K on the shoring so it is not cheap. Fortunately at the deepest points there are trees with roots to hold the soil together.

Construction certificate approved

Hooray! Our construction certificate is approved at last. Now Graham can really get on with it.

Sandpit

Well, I guess it comes down to just a sandpit after final demolition. I removed the drain and took out some of the fragments over the last two days. Even though it is sand, you see the soil holds up well.

The sand stone guy missed about twelve stones. Well hopefully only twelve.

Nearly gone

Graham got someone in to remove the last of the sandstone blocks. He came in with an excavator and dug them up and took them away in a truck. It took him a day and a bit. Now all that's left is a driveway and a bit of rubble.

More forms, more money

Today I took a bunch of forms to council along with a bank cheque and a wad of notes. This time they didn't seem as organised as they have in the past. It took them a while to enter all the information into the computer, to find out how much I owed them. They weren't sure what a couple of the documents were that we'd been asked to provide. The person I was supposed to contact wasn't there. They thought I'd be able to take the approved construction certificate with me, but apparently it wasn't ready. Then when they sent me to the customer service counter to pay, I was quoted a different amount (they sorted it out quickly though). Apparently most builders don't use the council as their certifier.

Poor Louka quickly tired of the small number of Lego Duplo blocks provided to amuse kids, and she'd seen the architectural models before. But she was pretty good.

Construction Certificate Approved

I got a call from the council today. I just need to pay a heap of money and submit a letter saying I vow to conform the Basix(tm) certificate and the construction certificate is in the bag. Yay!

Drains Away

Today I spent my time removing the rest of the brick footings, the rear and side path and some of the sewer drain. The drain is sure hard work as it is buried quite deep. Interestingly it was a bit clogged from the shower and laundry but clean from where the toilet on. It was not smelly at all.

Tell Graham what you think

You may not have noticed, but over on the right there's a survey. You can tell Graham what you think of his blog, and who knows, he might even do something about it. But so far, there's only one vote (mine).

South Side Path Gone

I finished collecting my stack of blocks today - yay! I also made a healthy start on removing the concrete paths. I've mostly removed the path along the south side and managed to remove some of the brick foundations as well. I was thinking I might need to hire the jack hammer again for the foundations, but fortunately I was able to break it up with the trusty rusty crow bar.

It is getting dark early now. I had to wrap it up at 5:30pm. The Kimbriki recycling guys put me on the weigh bridge this morning - $34 instead of $11 - ouch. I was carrying 1.49 tons - just over my official carrying capacity.

One of the things about not having side braces with the gantry is that it allows one to walk it around. It does not detract too much from the strength since the feet firmly burrow themselves firmly into the ground.

The gantry and the block grab will certainly become handing in building a stone wall. I'll me able to simply lower the blocks effortlessly onto a layer of mortar.

Gantry 2.0

I though it would be prudent to ensure my stack of stones is a significant distance from the proposed dwelling. I found that, at the moment, it is probably about 1.2m away. But it does mean that I really should not consume more space with stones. This lead me to rebuild the gantry using a weaker, shorter, but less flexible 2x4 piece of timber. It worked well and my pile of stones is now around 2.1m high.



The rear neighbour has just about finished their renovations and they have put up a screen. It looks good!

Construction Certificate Submitted

Liz went to council and submitted the application for a construction certificate. It costs $1800 and it can take up to three weeks. Fingers crossed, we should get it soon after we get back from holidays.

http://www.warringah.nsw.gov.au/ecouncil/DA.aspx?cmd=3&land_no=14425&da_no=CC2009/0253