# Forum Home Renovation Sub Flooring  restumping depth sunshine 3020 victoria

## kevinmauseth

hi everyone i own a house in west sunshine 3020. I've decided to slowly replace it's redgum stumps myself.
the soil is heavy clay. house seems quite level and i can live with it not being perfect. From what i see on the internet, other people have been digging 500mm deep holes,
or just down to the sole plate. however today i removed a stump that was completely rotted through and dug down to the sole plate.
the sole plate was at 500mm and i dug another 50mm down expecting to find hard ground. But the ground was still soft i could push my 
index finger down 10mm. the clay is quite damp all the way down my guess is that is due to poor drainage or ventilation. my question
is can i embed concrete stumps into this or do i need to keep on digging.

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## plum

Not to do with stumps, but you may have an issue with stormwater drains if it's so damp.

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## r3nov8or

You should probably get a soil test done. And in my neck of the woods restumping requires a building permit. How much clearance do you have? it really is a tough gig. Have you gotten any quotes from restumpers for an in-situ job? (ie no house levelling)

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## OBBob

Are you replacing with concrete stumps and then mixing up some concrete for the baseplate and then backfilling with the soil?  
Agree it's a tough gig to do them all. The stumpers normally have specialist miniature guy's that are very efficient under the house. Then they get a concrete pump in to do the bases.

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## kevinmauseth

Thanks for the reply obbob I was going to use concrete stumps and use ready mix builders concrete.

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## Moondog55

Is this just for the stumps on the building perimeter?
I'd be happy to do those myself but getting under the house and doing 60 to 80 of them? No F????? way
Also I agree with Plum check the storm water as well, we haven't really had all that much rain
Around Norlane we have the same type of soil and 600 to 900 deep is normal, erring on the deeper side where at all possible and that's without soil tests
Dig a test pit and see what the soil profile is like

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## r3nov8or

> ...
> Dig a test pit and see what the soil profile is like

   ... Or try digging it while under the house to know what you are up against  :Smilie:

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## kevinmauseth

> ... Or try digging it while under the house to know what you are up against

  as mentioned in my original post i dug down and removed the sole plate. this was done under the house.

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## r3nov8or

> as mentioned in my original post i dug down and removed the sole plate. this was done under the house.

   Starting under the house rather than at the edge? That's a new one on me. 
Anyway, restumpers will use hanging concrete stumps, the ones with wire loops on two sides that you place tightly under the bearer and nail to the sides of the bearer. Once you've dug your holes to a flat bottom, hang the stumps (with malthoid between the stump and bearer) to leave about 200mm under the stump (to form a regulation sole plate) and fill with concrete about 50 to 100mm up the stump. Then backfill the rest with soil.

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## MorganGT

> Is this just for the stumps on the building perimeter?
> I'd be happy to do those myself but getting under the house and doing 60 to 80 of them? No F????? way
> Also I agree with Plum check the storm water as well, we haven't really had all that much rain

  Some years back I had a casual job in between careers helping an owner builder (actually the son of the house owner, who lived on a shelf in the shed in the backyard) restump a house in Whittlesea in preparation for a second storey extension, replacing the original redgum stumps with concrete and adding extra stumps to carry the added load. The house was low to the ground with maybe 25-30cm clearance under the joists so we did it room by room (with 3 people still living in the house) by pulling up the boards in a couple of rooms at a time, digging, jacking and hanging new stumps then pouring concrete to form a soleplate and continuing several inches up each stump.  
Eventually the job had to be paused partway through due to soil moisture issues - I'd just finished digging two 1 x 1 x 1 metre holes to take several stumps in each (specified by the engineer to carry  point loads from upstairs where the staircase was planned) when I saw some water appear in the hole. Went outside to tell the owner, and found myself standing in water - the aqueduct passing behind the house block had overflowed due to heavy rain, and the whole yard was starting to flood. Within 15 minutes the flood level had peaked at 1" up from the bottom of the joists and all the sand piled outside by the cement mixer had been washed under the house and into the hole. 
I found myself another job after that, but his building saga doesn't appear to have an end - every now and then I drive past and it seemed to take several years before the upstairs extension started - it's now at least 11 years later, and the upstairs seems to be framed, at least, but for the last 5 years at least it's been covered with a tarp, with no sign of a watertight end in sight.

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## kevinmauseth

i also wanted to know if anyone out their knew how long the concrete under a new stump needs to cure. i'm hearing anything between 2 days to 2 weeks. long drying times would mean i'd have to use jacks more effectively, get heaps of them or just replace stumps over period of a year.

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## Moondog55

Using the 36mPa stuff we had to leave the house for 12 hours and the jacks were removed in 24 but concrete keeps curing for a long time, years in fact This house was restumped in a day but digging the holes and removing all the old rotted stumps and sole plates took a team of 5 a 2 full weeks

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