House building questions

[Big Dog]

Perspective is an amazing thing...
You spent 5 years building one set of those a week would be far more impressive than you spent 5 years building one set of those...

Sent via tapatalk.

[Erelyes]

i spent half a decade building the cunts.

So anecdotal then, rather than based on anything published/technical.

And the good Christian folk doing our floors did 110mm in any case (4 1/3 inches in imperial parlance), even though we're not going with heated floors.

[Akzle]

5 years, you spent 5 years building the cunts.

have they changed the definition of decade recently? Or half?
You seemed to get the point correctly, either way...

[Akzle]

Perspective is an amazing thing...
You spent 5 years building one set of those a week would be far more impressive than you spent 5 years building one set of those...

Sent via tapatalk.

3 in a good week with an prentice under me. Four if we had the other cunt who knew what he was doing.

[Akzle]

So anecdotal then, rather than based on anything published/technical.

largely, yes. But a fucking stack of floors that arent fucked says i'm right.

But also if you look at it from a nengineering standpoint, the design is such that, had you a fork hoist large enough, you could pick the slab up by one corner with fuckall deflection. A neighty mil raft is insufficient to hold the slab under tension.

Concrete specifications typically require 50mm cover to any internal steel/formwork, ergo, with 7mm mesh (or 5, if you're cheap aucklander cuntface), minimum top requirement is 107mm.

But hey. Fucked if i care.

[flyingcrocodile46]

Standard ribrafts (80+%) are 85-90mm but it's not uncommon to see 100mm and very occasionally a little thicker. Eco pods or Cupolex (not sure of the spellink) can reduce to as little as 65mm over the middle of the domed pods. The reasons for thicker ribraft slabs are varied (trafficable, public use, Highly expansive soils etc are a few examples).

I'm one of those suspect fellas that "signs off on them" Maybe as many as a thousand of them. They are fine until you start doing un-clever things with the topping (like forming set-downs or drainage planes without reducing the pod depths). They are less likely to crack on expansive soils than a standard slab.

Not sure what all the fuss about insulation is for if it's only a garage (Use a comfy sleeping roll if you want to lie on the cold hard concrete floor under an oil pan). If I was the OP (and didn't want to burn through dollars for little return... for the stated use) I would put the top floor on poles with a free standing pole retaining wall behind/separate to and outside of the garage. Pour (and saw cut) a 100mm thick slab with polythene, SE615 or 62 mesh (with a 150 wide 250mm deep edge thickening) and close it in with non-load bearing 4x2 H3.2 wall framing and 6mm flat hardies (over 20mm cavity battens and wrap) with crappy plastic jointers. Insulate the floor above with some Cosy floor or similar to keep the habitable space warm upstairs. Of course the cladding choice can be modified to taste and budget.

The advantage of this plan is all financial and it can be gradually upgraded to legal habitable use (consented wall insulation and wall and ceiling linings) without any dead money having been wasted along the way (as long as it's properly planned and documented/consented with the DPM, wall wrap, joinery flashings etc and the exterior ground is kept 225mm below FFL).

Even if you pushed ahead and fully insulated and lined it, the saving over ribraft and masonry cost (with internal battens, insulation and wall linings etc to upgrade the masonry wall version to habitable space) would likely be around $25+K. And you don't need to worry about excavating behind retaining walls to fix leaks and/or silted up subsoil drains if it goes pear shaped down the line.

[flyingcrocodile46]

largely, yes. But a fucking stack of floors that arent fucked says i'm right.

But also if you look at it from a nengineering standpoint, the design is such that, had you a fork hoist large enough, you could pick the slab up by one corner with fuckall deflection. A neighty mil raft is insufficient to hold the slab under tension.

Concrete specifications typically require 50mm cover to any internal steel/formwork, ergo, with 7mm mesh (or 5, if you're cheap aucklander cuntface), minimum top requirement is 107mm.

But hey. Fucked if i care.

From NZS3604 section 4 (Durability)
Minimum concrete cover to steel reinforcement shall be:
(a) 75 mm when concrete is placed directly on or against the ground;
(b) 50 mm in all other situations where the concrete is placed in formwork provided the concrete specifications follow the provisions
of 4.5.2;
(c) 30 mm from the top of a wall or floor slab which is in a closed area or 50 mm from the top of any exposed wall or floor slab.

In the case of rib rafts, the pods satisfy the 75mm clearance to ground even if the steel is hard down on the pods so you only need 50mm between the poly and steel under 3604 and another 30mm above the steel (hence the acceptance of 85mm). However, Rib rafts are specific design outside the scope of 3604 and the design recognises the additional clearance provided by the pods, so the bottom clearance becomes more about correct placement for optimum load transfer. Even standard floor slabs only have to be 100mm. The bottom steel cover is able to be reduced where the ground is covered by a membrane (taped polythene) as strictly speaking the concrete is no longer placed "directly" on the ground.

An interesting side note on the performance of polythene DPM. Until very recently NZBC E2/AS1 (weathertightness Acceptable solutions) allowed the use of a single layer of .25mm polythene with taped joints (and 'protection' same as for every other DPM/WPM used as tanking) to waterproof masonry/concrete retaining walls.

[Akzle]

In the case of rib rafts, the pods satisfy the 75mm clearance to ground even if the steel is hard down on the pods so you only need 50mm between the poly and steel under 3604 and another 30mm above the steel (hence the acceptance of 85mm).

yes, but in terms of "whats actually a good fucken idea" and "whats legal" there is, as usual, quite some disparity.

You mean to tell me, you would sign off on a slab with the mesh on the pods? The fuck i waste money on chairs for?

-edits-
do you know how concrete works?

[flyingcrocodile46]

yes, but in terms of "whats actually a good fucken idea" and "whats legal" there is, as usual, quite some disparity.

You mean to tell me, you would sign off on a slab with the mesh on the pods? The fuck i waste money on chairs for?

-edits-
do you know how concrete works?

Yes. That is always a good argument (better safe than sorry) though for most applications 85mm is sufficient. It comes down to ground conditions (that are often mitigated by piling below areas of the raft perimeter). The depth of the ribs do the lions share of the work (with respect to tension in your fork lift scenario) and they can be further strengthened with extra rebar in the more common reverse scenario.

No. I was pretty clear that a minimum of 50mm is desirable. Certainly wouldn't sign off on less than 30mm without convincing peer reviewed calculations.

[Grumph]

No. I was pretty clear that a minimum of 50mm is desirable. Certainly wouldn't sign off on less than 30mm without convincing peer reviewed calculations.

Amusingly enough, I watched the breaking up and removal of a garage floor slab yesterday at my daughter's house.
Onto an existing sealed area, a ring foundation had been dug to about 70mm below GL. Boxed and reinforcing put around the edge. A half sheet of mesh at one end too...Then backfilled with crappy fill and poured. Edges probably 120mm at the deepest point. In the center it was around 20mm thick...

I would not have liked to jack up a car anywhere close to the center of that floor....

[swarfie]

Amazing what some miserable mongrel builders get away with when the 'council inspector' has his back turned. When we bought the house we currently live in we wanted to put in some alarm and phone wiring for my shed out back which required running them through the ceiling, down outside wall and underground to the shed. Couldn't find an access hatch anywhere so had to cut a hole in the back of my daughters upstairs wardrobe. I looked in....no insulation in the ceiling space. Rockwool in the walls but nothing in the ceiling. Found out later the arsehole builder had charged the first owners for the insulation and just stuck it in his pocket.....frigging bottomfeeder
The useless Tron City Council wouldn't even get off their arse and do anything about it (even though the wank "builder" had a reputation for this sort of thing as we later found out). It wouldn't surprise me to find out the 'inspector' wasn't slipped a back pocket bribe to look the other way either. Ended up costing us to insulate the place.

[SPman]

If there was no access hatch, the inspector couldn't look.
Then again - no access hatch, the inspector shouldn't have signed off on it!

[Akzle]

It wouldn't surprise me to find out the 'inspector' wasn't slipped a back pocket bribe to look the other way either. Ended up costing us to insulate the place.

yes or no. It wasnt that long ago in dorkland that the chineses were getting pre-line inspections signed off.

...then going back and removing every second stud and half the nogs, (to be reused at the next house) before whacking up gib and fucking off.

[Erelyes]

whacking up gib and fucking off.

Better than them fucking up gib and whacking off.

[oldrider]

yes or no. It wasnt that long ago in dorkland that the chineses were getting pre-line inspections signed off.

...then going back and removing every second stud and half the nogs, (to be reused at the next house) before whacking up gib and fucking off.

I know of a NZ "Masterbuilders" member who used to do just that - did it for years on certain government contracts was well known for it - got away with it!

There have always been a % of shysters out there - probably always will be!