Sunday 22 July 2018

Building in NZ - From building consent to foundations

 Getting the building consent proved not quite as straightforward as I expected. The working drawings done for the Council took almost double the time my builder had orignally told me, delaying things. The council then requested additional drawings for the chimney, despite the fact they have not requested them for the same type of chimney before for other clients.

I have the temerity to want shoulders on my cute little 'traditional' chimney. Silly me for not wanting the usual 'box' shape. Council farms this consent work out to various organisations so there's not a lot of consistency and it takes more time. Council staff themselves are probably not doing a lot of pouring over your drawings.

There was a further delay and also expense because, again, I was selfish enough to want to access my section via a driveway. You what? Yep, my house is NEAR an intersection (not on it) so I was told I would need a Resource Consent. Is it no wonder we love to hate council bureaucracy? I'm in a modern subdivision. You'd think that council consent for a subdivision to go ahead would assume homeowners would be able to build their driveways automatically. Nope.

Following the issuing of the consent a surveyor was sent to survey the section ready for excavation and to take GPS coordinates. Lucky for me, I suppose, I am unemployed and very motivated to avoid mistakes. I did a drive-by of my section to see what the surveyor was up to. No-one was there. I drove on and found a surveyor nearby busily doing his thing with his equipment on another section so I got out of the car and said
 "Are you sure you are surveying the right property? I'm expecting a surveyor for my land today, there's the truck with the digger on it parked beside the fence."
"Oh yes, it's all fine, I've got the coordinates here," said the very young guy who seemed to talk about the hooss rather than the house, determined to ignore me. Well, what could I do?

I got back in my car and drove away but I felt very uneasy. "Stuff it! I said to myself, better an embarassment or confrontation than an expensive, delaying cockup." I drove back to the guy and said "I really think you should check because my surveyor is missing, this section you are on has not been sold. See, no SOLD sticker." I stood my ground. He walked away and called his office. I couldn't hear what was said but he came back and said "Yeah you are probably right but I would have worked it out eventually," he nonchalantly quipped. My jaw dropped.

Later, I drove past to see him checking the GPS coordinates on MY section. I phoned my builder and informed them of the mistake. Almost half the day had been lost. They really appreciated my vigilance as a day lost stuffs up all subsequent trades booked in. Construction is so busy in Rolleston you can't risk a tradie being unavailable because the schedule changed. I had no confidence in the surveyor and told my builder so. "Someone needs to check his work, I don't want my house positioned incorrectly."
The builder came back to me and said it was the first time they had had a problem with that surveying company which was very sorry and embarassed. I was now feeling nervous about everything.

 Surveying done, the excavators fired up the digger and started carving into my virgin ground. What a lot of earth gets unearthed. As predicted, there were quite a few stones in it but less than I expected.
The excavators mark out the house footprint, dig down and then have an engineer test the ground all over where your foundations are going to go. Bad news, the engineer said that the  foundations would have to be excavated a lot deeper than originally planned. This will require significant extra costs to me as the contract always has an 'out' regarding increased costs for foundations since one cannot know the soil issues in advance of excavation.

Important note: If you need cables/conduit for outside lighting your builder needs to know your exterior lighting plan well in advance so pipes can be put in before the slab is poured. The plumber will also come and put sticky-out pipes into the base before they pour for your water supply/toilet/shower. If you are having a tiled shower you will see the shape of it in the pour. You will also see the rebate in the concrete for your eventual garage door.

Gradually the foundations took shape. After digging the soil out metal is piled in and compacted until the levels are right. Then sand. The boxing is done and a polythene moisture barrier is laid out on top and up the sides. On top of this reinforcing rods and placeholders are laid. Another inspection is done and then you are allowed to pour.

My foundation is a single-pour slab. I am told this can knock a couple of days off the foundation stage otherwise two separate pours take more time and are more ugly with a seam running around the foundations.

For more detailed info on NZ residential foundations go to:
 https://builderscrack.co.nz/blog/2015/03/04/house-foundations-pros-cons-3-different-types/
http://www.seismicresilience.org.nz/topics/foundations/residential-foundations/nzs-3604-type-foundations/http://www.seismicresilience.org.nz/topics/foundations/residential-foundations/nzs-3604-type-foundations/
https://www.renovate.org.nz/1970s/foundations-and-subfloors/foundations-original-details/concrete-slab-floor-construction/https://www.renovate.org.nz/1970s/foundations-and-subfloors/foundations-original-details/concrete-slab-floor-construction/
http://www.seismicresilience.org.nz/topics/foundations/residential-foundations/shallow-foundations-residential/http://www.seismicresilience.org.nz/topics/foundations/residential-foundations/shallow-foundations-residential/

Patience is required at this stage because it takes quite some time. You've got to get it right. The foundation guys were great and explained things to me. Some houses use a 'raft' system of polystyrene instead of heaps of metal and sand, especially to counter earthquakes but my guys said "This house is so solid now it's not going to budge unless there's a cataclysm." Solid as... And look how tidy and smooth my slab is, better than many.

Slab poured. OK, the boxing comes off now, slab is polished, and then expansion joints need to be cut in.  I am informed that winter's not a bad time of year to pour a slab as it slows drying thus increasing hardness. A shower of rain arrived to help keep things slowly curing.

Another council inspection and off we go for the drainlayer who takes more than a week to dig (agghh, Battle of the Somme returns) and lay pipes. Very messy and lots of stony ground dug up. He lays a base under the pipes so they don't sink then fills things in but I have useless earth left over. More dollar signs = get rid of it later. Really, when you build you have NO idea how much you will pay even with a fixed price contract.

The end of this stage has incurred days of delays due to the guy working alone and a day of rain mucking up inspection appointments, then backfill.
Next stage is exciting; the framing goes up.
















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