# Forum Home Renovation Sub Flooring  New build - engineer has recommended timber stumps?

## ebf

Hi guys, 
Commencing a new build soon and the engineer has come back with what to me seems like the worst possible option - timber stumps cast into the concrete. 
This seems like a rather arcane method - and especially so given the house we're building. Our house's height off the ground isn't high - shortest to longest distance is 0.4m to 0.86m. Soil is class M, so not too bad either. 
Can anyone think of a reason why the engineer would recommend this? At worse, i would have thought timber stumps screwed into a concrete pad level with the ground - though I would much prefer steel stumps over timber in any event. Here's the engineering below:

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## sol381

cant see anywhere where it says timber.. stumps can be steel.. Im sure its 75 x 75  steel.

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## ebf

It does elsewhere in the engineering, specified as F7 seasoned timber - I would assume there would be an equivalent of steel for F7 timber that I could just swap it out with, yes?

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## sol381

indeed but ask the engineer to change it on the plan, dont just do it..some engineers are lazy and just use generic drawings. id use 75 x 75 x 4mm hot dip gal.

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## davegol

> I could just swap it out with, yes?

  Maybe it's the engineer that needs to be swapped out ?   :Yikes2:

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## Optimus

If using steel his drawings will have to change.. you need to pour the concrete in a "coned" fashion 100mm above ground level so no water can sit against the steel stump.  
At that height I'd personally use 100x100 concrete stumps. Heaps cheaper than steel and no different to steel

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## sol381

100 x 100 concrete stumps.. where ringtail.

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## Optimus

> 100 x 100 concrete stumps.. where ringtail.

  Haha obviously not in Victoria

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## ebf

Thanks Optimus. 
Looking into steel in more detail and it unfortunately increases the price heaps. Not for the stumps so much but the connectors really blow the cost out. 
I see concrete is only slightly more expensive than timber, plus the threaded ones will be easy to put in place. What's the expected lifetime on concrete stumps - i'm assuming as good if not better than treated timber?

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## Optimus

> Thanks Optimus. 
> Looking into steel in more detail and it unfortunately increases the price heaps. Not for the stumps so much but the connectors really blow the cost out. 
> I see concrete is only slightly more expensive than timber, plus the threaded ones will be easy to put in place. What's the expected lifetime on concrete stumps - i'm assuming as good if not better than treated timber?

  Timber (treated or not) will just rot out eventually.. 
Concrete stumps will last your lifetime. 
As for price, 100x100 cypress is more expensive per lineal meter than a 100x100 concrete stump here in Melbourne. 
It's a no brainer for me.

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## ebf

Great, thanks again. 
One last question - for timber stumps I was going to place bearers up and hang stumps from the bearers into the holes and then pour concrete. Can the same be done for concrete stumps - i would assume perhaps not due to the weight?

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## Optimus

Yep.. that's the way i build decks or extensions, i use bottle jacks and brace the bearers with some of the joists.. 
Only downside is it makes it harder to pour the concrete if you are doing it by barra as the bearers and joists and some braces are in the way. 
I then use a concrete pump. So much easier, trust me its $400 (pump hire) well spent

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## Optimus

Also that way you can use threaded concrete stumps instead of builders stumps.

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## Optimus

You could just set up a few hurdles.. 
Also use this http://kordontmb.com.au/kordon/about...Kordon_tmp.asp 
Instead of antcaps

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## OBBob

I just set up hurdles and string lines. Then once the stumps were in I hired a laser lever and packed any that needed it. I was surprisingly accurate and just needed a coupled of cement sheet packers in a few spots.

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## METRIX

I would be getting the bricky to brick up piers for you, that's how we do it in NSW, pour the footings, set up profiles let the bricky do the rest. 
Steel would be the next choice, timber would be my last choice, I know in Vic concrete stumps are used extensively, we prefer brick piers in NSW.

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## sol381

your land seems very flat just wondering why you aren't just going slab on ground.

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## phild01

+1 for brick piers :Wink:

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## manofaus

I have just done a bit of research for this very thing.
For the cost I would do full concrete piers in the ground with 75 SHS embedded. Another option is a steel stump dyna bolted to the top or use strapping embedded in concrete. Approx $60 a post. (with adjustable head)
You could always do a screw pier or helicial pier. 50yr guarantee. $55~65m installed. Done in a day. Just level and add a top and away you go. 
Only problem is how to hide your piers or posts when they are steel. Thats the main advantage of using brick piers. Pretty sure you need to run some sort of strapping or threaded bar in the concrete if you are going to use brick on all external walls. 
FYI BCA calls for a clearance under your bearers of minimum of 400mm.

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## ebf

Thanks again guys. 
Sadly, finding a supplier of concrete stumps in NSW is looking impossible. I'm not a fan of brick stumps - so that leaves steel or timber... unless I make my own concrete stumps....

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## phild01

> Hi guys, 
> ...and the engineer has come back with what to me seems like the *worst possible option - timber stumps* cast into the concrete.

   

> I'm not a fan of brick stumps - so that leaves steel *or timber...*

  Can't beat bricks.

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## sol381

Cant see how brick stumps are cost effective.. Footing has to be much larger.. Have to pay for bricks and bricklayer.. Steel is light, easy to concrete in and easy to attach bearer to. If you can weld then it will save you heaps just buying the posts and plates. Have to say never seen a 100x 100 concrete stump up here in qld.. Must be a victorian thing.

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## phild01

> Cant see how brick stumps are cost effective..

   Didn't say brick 'piers' are cheap, just better.

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## Optimus

> Didn't say brick 'piers' are cheap, just better.

  Better in what way? 
How do you brace the brick piers to each other when they're high out of the ground?

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## METRIX

> . Have to say never seen a 100x 100 concrete stump up here in qld.. Must be a victorian thing.

  Yep, it's a Victorian thing

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## phild01

> Better in what way? 
> How do you brace the brick piers to each other when they're high out of the ground?

  you don't, and op is not qld, so I doubt he is reaching for the sky :Smilie: .

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## Optimus

> you don't, and op is not qld, so I doubt he is reaching for the sky.

  So there's no sloping blocks in nsw? 
So are you saying you have brick piers built up 2 meters (ish) without any bracing? 
Wowieee! 
How are the piers attached to the bearers?

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## phild01

Houses in the sixties were built high on piers when the land sloped.  It is not a problem.  The low lying part of the house had a partial perimeter brick foundation wall that braced the structure well.  The high piers are bigger in the lower part.  The thing is that brick piers offer bracing and factored in.
  The structure rests on the piers, all that is necessary and doesn't blow away.

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## ebf

How would you get the bricks to the right height - with timber and steel you cut to size - with brick stumps would it make the concrete base height absolutely critical? Sounds hard  :Shock:

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## manofaus

your concrete pad is what you get to the correct level. As you go down a slope you just minus a multiple of the course of bricks. If the concrete is off they fudge the mortar to gain or lose height. Have even seen bricks laid on there edge or cut in half when piers are low. 
Are we getting things confused? A brick Pier sits on a concrete footing that is level if not just higher then the ground. The concrete piers or timber piers are set into the ground and protrude from the ground to directly support your bearers.

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## ebf

So ended up with steel posts in the end - concrete stumps just don't seem to exist in NSW. Used Levelmaster heads which are great - same price as Unipiers but far more flexible.

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## manofaus

so was it concrete with posts embedded?
Do you mind sharing the details of construction and cost?
Thanks

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## ebf

> so was it concrete with posts embedded?
> Do you mind sharing the details of construction and cost?
> Thanks

  Steel was 75x75x2.5mm gal - three eight metre lengths cost me $300. After cutting them to size i drilled a hole 150mm from the bottom and inserted an m12 bolt to give it something to anchor into the concrete. 
The heads from levelmaster were $40 each - including shipping it cost me around $1,200. So total price was around $1,500 - that's around double what I would have paid for timber, but given the huge increase in longevity of steel, it was well worth it.

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## Optimus

Suprised you didn't weld a plate to the bottom of them.. 
You should also build the concrete up minimum 100mm out of the ground and slope it away from the stump so water can't sit against it.

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## havabeer

> So there's no sloping blocks in nsw? 
> So are you saying you have brick piers built up 2 meters (ish) without any bracing? 
> Wowieee! 
> How are the piers attached to the bearers?

  this is basically my house, I have some piers around the 1.8m mark with no bracing, bearers aren't strapped either

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## Optimus

> this is basically my house, I have some piers around the 1.8m mark with no bracing, bearers aren't strapped either

  Ya learn something new everyday!

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## phild01

> Ya learn something new everyday!

  Worth considering that these houses are typically hardwood framed with internal load bearing framing,  and tiled roofing.  So as a structure they are quite heavy, unlike today's light timber framing. 
What I find a bit surprising is the increased requirement for tie-down, in the southern part of Australia.

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## Uncle Bob

> . 
> What I find a bit surprising is the increased requirement for tie-down, in the southern part of Australia.

  Climate change

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