Who This Hillside Guide Is For

SPEAKER_01 0:00

If you're living on the hill or looking to buy a house on the hill, this is the episode for you. I've got Evan back in the house. Hello, Evan.

SPEAKER_00 0:06

Hi.

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We're going to talk about retaining walls and hillside sections.

SPEAKER_00 0:10

Yep, that's uh Wellington tour tea.

SPEAKER_01 0:13

Well, I've just come

Retaining Walls And Hill Sections

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back from Dunedin and I'm like, I saw a lot of houses in Dunedin that's sort of on the hill as well. They don't have much flat land.

SPEAKER_00 0:20

No, not like not like Caperty, yeah.

SPEAKER_01 0:22

No, so Wellington, Dunedin, a few other parts of New Zealand, hillside. What should people really pay attention to?

SPEAKER_00 0:28

So unretained areas, I guess when it comes to buying a house on a hill and seeing if there's

Geotech Reports And Unretained Ground

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been any geotechnical reports done. So how stable is the the ground compared to, you know, like where the house is, if there's going to be any impact of any instability of unretained sections. If there are older crib walls installed, so they're the older style retaining where they kind of interlock sections and they go back about like a meter into the ground, but all you see is like this crib face. So that's quite common. And just generally how a house is built into the hillside as well.

SPEAKER_01 1:18

Are they normally like drilled on piles?

SPEAKER_00 1:20

Yeah, so I I built our first home up in Mangaroki in Lower Hutt on the Western Hills, and we had

Building On Piles On A Slope

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so we had a a small block retaining wall at the back that anchored into the hillside, and then from there the house was kind of tied there and it went out maybe about five or six metres out from there, and because it was on a hill, I think the very outer poles were about 12 metres long, and they went into the ground about three metres.

SPEAKER_01 1:56

Wow.

SPEAKER_00 1:56

Yeah. Yeah.

SPEAKER_01 1:58

That's a lot of drilling.

SPEAKER_00 1:59

A lot of drilling, yeah. It's um it's quite scary, you know, building a house when you're nine, ten metres up and you're walking around on a scaffold and or just on the build platform and you you look down and there's a nine metre drop, you're like, whoo. Especially up in the western hills where it gets quite windy.

SPEAKER_01 2:19

But the views must have been worse.

SPEAKER_00 2:21

Incredible, yeah. 100% incredible. And we had a massive deck on the on the western face of the house. I think it was about 75 square meters in total.

SPEAKER_01 2:30

But like maintenance-wise, if someone was to buy a house like that, which they probably did, like what what are the risks there? What are the pros and what are the cons?

SPEAKER_00 2:41

I mean, maintenance-wise, it was actually a pretty low maintenance house. It was it was a single story, and because the deck wrapped around the entire house, or well, the majority of the house, and then there was easy access out the back, you could actually access the entire cladding pretty easily off a ladder. Okay. So it wasn't it wasn't too bad. Yeah.

SPEAKER_01 3:04

I'm I'm still like stuck at the heights. Yeah. How scary it would have been.

SPEAKER_00 3:09

Yeah, I mean, and and because it was built into the hillside, I think we had three retaining walls on the section. One that ran all the way along the back side of the house, I think that was about 25 metres long, and they all had to be drilled in about three metres into the ground. There were some areas where we just physically couldn't. So we got the the digger driver when he was augering out the holes for us.

Drilling Into Greywacke Reality Check

SPEAKER_00 3:37

I remember it hit about two metres, I think it was, and the the auger just started smoking in the in the bottom of the hole. And it'd pull it out, and there would be nothing, nothing come out. And so we ended up having to get the engineer to come on site, pay for a site visit, to tell him that you physically couldn't drill any further because the drill just wouldn't go in. And we're not talking about a small digger, we're talking about you know, eight-ton digger or whatever it was. Yeah.

SPEAKER_01 4:06

Why why it couldn't dig in? What what are the elements there?

SPEAKER_00 4:09

It was grey wacky rock up there. So when when it it just got too hard, it got too hard at at one point, and even with the we got a new auger bit with a tungsten cardboard tips, so it should really be eating into anything. That was still smoking at I think about 2.4 meters. And the engineer came on site, he saw it smoking and was like, Oh, yeah, no, we'll sign it off. We're just like, Okay, cool. Like, I know that it was specified for three meters, but you physically have seen that we literally can't dig any further than that. And some holes we got to three, and that was great, but some holes just And it's still safe.

SPEAKER_01 4:49

Yep. Okay. So what should people watch out for if they are looking to buy for house on the hill? What are the red flags that they should go? Oof, I don't know about that one.

SPEAKER_00 4:58

Subsidence.

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What is

Red Flags Like Subsidence

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that?

SPEAKER_00 5:01

So settlement to the ground. If paths are uneven, if there's significant cracking to foundations or cracking to cladding, dropping in windows. So I've done a couple of inspections where the window was just out of level, probably by about 30-40 mil, because the corner of the dwelling had dropped about like 50 or something, and so the kind of dragged the whole window down out of square. What else? Yeah, failing failing retaining walls. Anything that's straight up and down, plum, be careful of that. Most retaining walls, especially newer retaining walls, they have to have the right degree on them because any surcharge on the wall should stop if it's already straight, and a surcharge gets put on the wall, it's going to start tipping over. So it has to be whatever's specified by the engineer.

SPEAKER_01 6:07

Because there have been some significant slips in that region. Yeah. And some houses did go down.

SPEAKER_00 6:14

Yeah, I have a friend

Slips, Storms, Insurance, And Access

SPEAKER_00 6:18

of my wife's best friend in the I don't think in the last big storm, but I think the one before the hillside collapsed into the house, came into the bedroom.

SPEAKER_01 6:29

Whoa.

SPEAKER_00 6:30

Yeah. Yeah. And then the insurance wouldn't pay out.

SPEAKER_01 6:34

Why is that?

SPEAKER_00 6:35

I'm not too sure. I didn't see any like geotechnical. I didn't do an inspection on the house or anything, so I'm not too sure why it got denied. Access wise, it would have been an insane job to try and do because it was a pedestrian access only. You probably would have had to, I don't know, either do it all manually or maybe helicopter a digger in. But there was no physical access with machinery up there. And you're talking about tons and tons of removing dirt and then trying to install a retaining wall within a you know a metre of the house or whatever it ended up being. And that would have had to be, you know, pretty similar to what my retaining walls would have had to go at least two, three metres into the ground, most likely. And yeah, you just physically can't get like hand-powered stuff. You can't hire those kind of tools from you know high pool or bunnings. Ken arts, yeah, yeah, yeah.

SPEAKER_01 7:41

Wow, that's crazy.

SPEAKER_00 7:43

Yeah.

SPEAKER_01 7:43

So there are yeah, extra risks for people to really watch out for if they are looking to buy something on the hill or has a bit of an elevation.

SPEAKER_00 7:52

Yeah.

SPEAKER_01 7:52

And what can go from there. Beautiful. Thank you so much, Evan. Anything else to add to that story?

unknown 7:58

No.

SPEAKER_01 7:58

Any words of wisdom from your learning experience of building yourself on the hill?

SPEAKER_00 8:04

Get a builder that knows what they're doing. Yep. It it it does take a little bit of a

Choose A Builder Who Knows Hills

SPEAKER_00 8:09

specialist to, you know, work at heights and and and whatnot. Not every builder has come across that kind of stuff. A lot of builders will just build on flat, you know, new builds and townhouses, they're all pretty flat sections and all the earthworks are already done for them. So if if you are doing building work yourself, going with a a private company, I guess, kind of see what work they've done in the past and if they specialise in that kind of area, because it may cost a little bit more than someone else, but at least they know what they're doing.

SPEAKER_01 8:43

Exactly. And you can't take a bigger risk with that, like once yeah, once it goes down, goes down. You just reminded me actually with piling and drilling. I have a neighbor next door and he put his house on piles. And when they were drilling, my whole house was shattering. And I was worried

Neighbour Drilling And Final Wrap

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for my own house, thinking, is my house gonna go down the hill? Because this guy has been using some powerful tools there.

SPEAKER_00 9:05

Yeah. No, you'll be fine. Just rocks at bone. That's fine.

unknown 9:09

Okay.

SPEAKER_01 9:09

Well, we're on sand, so it sort of tends to move a little bit. Awesome. Thank you so much, Evan. Stees and see ya.