GRIPES

[spacesailor]

A LOT like having a '' Wing load '' factor , for 95-10 category . IS it in any other category ? .

spacesailor

[Old Koreelah]

1 hour ago, willedoo said:

… For their ego, and an easier experience with them, best to let them think that. Hence the bait of leaving some small thing not completed on purpose so they can feel good about themselves by educating you.

In had a school principal like that; we learned to use that tactic to keep him happy.

I called out my first building inspector for each stage of my house build until he gave up coming- too many other priorities. It seemed he was well satisfied that I was over-engineering the place. 

[willedoo]

Back when I built my place you didn't have to complete an owner builder's course like these days. From memory, you had to have an owner builder's permit from council which wasn't expensive. I already had experience building and just went by the standard TRADAC manuals. At the time, our top wind category was W60 (60 metres/second). Council stipulated W41 for my site, but I built quite a lot of it to W51 standard, and a fair bit of the tie-down to W60.

 

I learnt quite a few things from those manuals. My place has a cathedral ceiling, around 38 degree roof pitch, so it's a steep pitch. I was surprised when I looked up the tables for tie-down requirements to find it was a lot less than a standard 22 degree roof pitch. The reasoning is that a flatter roof will get a vortex of wind on the roof slope causing a greater uplift force. In other words, it's trying to suck the roof off. On the other hand, the wind hits a steep roof like mine with blunt force and the wind is less inclined to curl in a vortex. Correspondingly, the steep roof cops more sideways force, so the building needs more bracing than the flatter roof. So it's flatter roof - more tie down, less bracing, steeper roof - less tie down, more bracing. 

[willedoo]

I always use the theory with tie down that fixings are so cheap, why not use extra. If requirements stipulate one triple grip per rafter, it's no trouble to put a triple grip both sides of the rafter. Very little extra work and expense gives you double the tie down specs.

[rgmwa]

4 hours ago, facthunter said:

When building where I am now I put in heavier than needed exposed beams for the looks of it and the engineer from Shy  Cancel said "that Beam is too big" and I said yes but inside it is the exact  sized one you want. %$@*%%! Rock Apes/ Oxygen thieves. Wouldn't work in a tub of yeast.  Nev

He couldn’t have been a real engineer. A proper engineer would never say a beam is too big.

[facthunter]

It was exactly the term he used. Bigger than you needed would be OK. I really thought he was Joking... But NO.. Nev

[Bruce Tuncks]

Once, I left out the hold-down bolts for a roof, yep it was just sitting on the walls. I did it deliberately ( It was held down by tech screws, and these had just been removed. The next job was to drill them out and put in the nuts n bolts.  My plan was to praise the inspector effusively for finding out my trick.

In the event, he didn't notice so I said nothing to him but told the rest of the town. There was no wind this day.

[Bruce Tuncks]

In Darwin, it had become standard practice to just put threaded rod down the first concrete-brick row to hold the roof trusses down. This was before Tracy.

[old man emu]

Someone here said they were chipped because footings were square, not round. I waa thinking, "isn't a curved surface better at handling pressure than a straight one?" Think about the body of a pressure cylinder. It is a cylinder with between a sphere. 

 

Don't know diddly about engineering, just thinkin'

[willedoo]

ome, I think you have a point. Imagine a steel pole in a square footing undergoing lateral stresses. You would think the footing corners would be a weak point subject to stress fractures. In other words, if the footing was to split vertically, the corner is the logical point.

[old man emu]

I do know that if you want to stop a crack spreading in a sheet of metal or perspex, you drill a round hole at the ends of the crack. I don't know the physics of why it stops the crack, but it do.

[facthunter]

The hole stops the crack which is self perpetuating and the hole is harder to start a new crack from especially if it burnished to put the surface into compression.  Nev

[Marty_d]

Concrete footings are subject to compressive forces from the weight of the building above, but unless you're on very volatile ground, not laterally.  And if your reinforced concrete is not handling that then your walls have already fallen down.

I can't see that square footings would be any weaker than round, just more expensive as there's more concrete in them.

[rgmwa]

Rigid square and round footings of the same area will produce the same average bearing pressure although the deeper subsurface pressure distribution will be different for each. Square footings are almost always used simply because they are easier to form up and reinforce than round ones. The corners of a square footing are not prone to breaking off because the maximum bending stresses are in the centre of the footing.There are situations where a round footing is more appropriate, such as the foundation for a major airport control tower, water storage, wind turbine or power station chimney, but typical building footings are square or rectangular because those shapes are more practical.

[willedoo]

11 hours ago, rgmwa said:

Square footings are almost always used simply because they are easier to form up and reinforce than round ones

 

11 hours ago, rgmwa said:

but typical building footings are square or rectangular because those shapes are more practical.

That applies to standard building on slab construction. Earlier, I probably didn't clarify, but was referring to pole and stump construction footings when discussing round footings vs square. Almost always round (round augers); also much easier hand digging a round hole vs square.

[rgmwa]

5 hours ago, willedoo said:

 

That applies to standard building on slab construction. Earlier, I probably didn't clarify, but was referring to pole and stump construction footings when discussing round footings vs square. Almost always round (round augers); also much easier hand digging a round hole vs square.

Yes, I missed that. Round post footings are the norm.

[willedoo]

When I look back at the number of fence post holes and house and shed footings I've dug by hand with a shovel and crowbar, it's no wonder I'm getting a carpal tunnel op next week. Most of my place is rocky, so involves a fair bit of jarring with the crowbar. The only fence post holes I was able to get in with a bobcat and auger were along my front boundary where there's a good depth of soil. Drilling holes saves a lot of work, but if the ground is grassy, sometimes you don't end up with enough dirt to fill around the post. You lose a lot in the grass, and of course you are also compacting the soil back in the hole at a higher compaction rate than the natural soil.

 

Luckily, I haven't got clay. Hand digging post holes in heavy clay should be reserved for only the harshest punishment.

[facthunter]

Post hole diggers on the back of a Fergie would have to rate as one of the most dangerous of all farm implements. I had a total of 45 Kms of vine rows at the grape farm. .  Nev

[willedoo]

Nev, what type of soil did you have? I remember with planting trees in bored holes, if there was a fair clay content the auger would glaze off the sides of the hole. We had to punch holes in the side of the wall with the crowbar to get some drainage. That was in a 60" rainfall area.

[facthunter]

Sandy Clay Loam it was called with a boron base at about 27 cms which effectively prevented roots going down deep unless you used a ripper to get through it. Very Alkaline. Ph around 10.  Old ocean bed I think.. Mallee country. Grow anything if you treated it right (and HAD WATER and drainage).. Nev

Edited April 28, 2023 by facthunter

[Bruce Tuncks]

Wow I'm impressed by the technical expertise here. It would all be way beyond the ability of the west wimmera inspector to understand for sure.

I actually heard today that the round auger-type of hole had compressed soil in the circumference and would therefore be stronger!

The book said 90 cm diameter footing holes and they built 90cm square holes. 

when, 20 years ago, the guy was drilling footing-holes for a farm shed I was building, he was amazed that I wanted them 90 cm deep.

Never before had he been asked for such deep holes, he said. But I was only following the instructions in the shed manual. I reckon, with hindsight, that half this depth would have been ok.

[Bruce Tuncks]

Nev, I heard that arsenic was found in some USA soils and it rendered the soil unsuitable for horticulture.

All I know is that soils here are often deficient in Phosphorous, and that Arsenic is grouped with Phosphorous on the periodic table.

Has anybody ever heard about Arsenic being a problem in soils?

[willedoo]

54 minutes ago, Bruce Tuncks said:

Wow I'm impressed by the technical expertise here. It would all be way beyond the ability of the west wimmera inspector to understand for sure.

I actually heard today that the round auger-type of hole had compressed soil in the circumference and would therefore be stronger!

The book said 90 cm diameter footing holes and they built 90cm square holes. 

when, 20 years ago, the guy was drilling footing-holes for a farm shed I was building, he was amazed that I wanted them 90 cm deep.

Never before had he been asked for such deep holes, he said. But I was only following the instructions in the shed manual. I reckon, with hindsight, that half this depth would have been ok.

45 cm is a bit shallow, even with good diagonal bracing. 75 cm would probably be a good compromise. From memory when I built my place, the code at the time stipulated 90 cm minimum depth for the house stumps, or where rock was encountered at a shallower depth, to key the hole 30 cm into the rock. I built on a slope so went down to rock with all the holes, and then jackhammered a level punching pad in the bottom. The shortest stump on the high side is the minimum allowable 45 cm from ground to bearer, and the stump on the lowest side is nearly 4 metres out of the ground.

 

That one was a pain in the rear to dig by hand, about five and a half feet deep. Because I had to have shoulder space to work in the hole, I had to increase the diameter = more digging. Then it was too deep and narrow to get the jackhammer down the hole, so to chip the base rock level I had to use the crowbar like a percussion drill. I can remember standing upright in the hole and looking at a cane toad at eye level; he'd hopped over to the rim of the hole to check me out.

 

For a standard cow fence, strainer posts are normally 3' (90 cm) in the ground and in between posts 2' (60 cm). With a strainer post hole, don't even think about the tape measure until you start having trouble getting the dirt out with a post hole shovel. If you're getting it out without losing it from the shovel, you still have a long way to go.

[pmccarthy]

Arsenic is associated with sulphur, iron, quartz and gold. Bendigo is a giant arsenic anomaly. Natural arsenic levels in the soil there are way above what EPA would accept if not natural.

[onetrack]

Many shed uprights come out of the ground thanks to being lifted out by ferocious winds. As a result, plenty of concrete in footings is better than less concrete, and it doesn't really matter whether the footing is round or square. But a footing that is wider at the base than at the top is going to be more difficult for any savage wind gust to lift out.