# Forum Home Renovation Sub Flooring  Replace Concrete piers with Steel

## Craigoss

Hey guys, 
I own and old brick cottage, which had a timber extension added on back in the 70s. Several piers on the back of the house has sunk about 20-30mm over the years. There is quite a bow in the floor where one of the piers has sunk the most. I'm looking at fixing the piers and re-building the subfloor to get everything level (in order to lay new floorboards). 
See a picture of the concrete piers in question. 
I'm considering replacing these piers with steel, along the lines of the uni-pier posts, website Uni-Pier Australia  
I have a few questions: 
1) Do you think it would look odd or look poorly when i go to sell the house if part of the extension has brick piers and the other half has steel?
2) Is the general approach to install: lift/support the piers using a bottle jack, remove the pier, dig new footing, bolt on new steel pier, and finally pour footing?
3) What footing depth is recommended? Obviously a difficult question to answer without a soil test and engineers report. The extension is made from timber, single storey and only has a colorbond roof. I know i should get an engineers report, but i'm thinking that any footing I put in will be better than what was originally there and i'm happy to over engineer it. I was looking at digging a 450x450x600mm hole possibly deeper depending on the hardness of the soil. 
Any feedback would be great. 
Thanks

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## autogenous

Jack up the joists and pack beneath them with compressed fibre cement sheeting? 
Had an old house once. Love them to death.  There's something very appealing about them. 
Maybe they're missing the sound of mass production? Some of them have enormous detail.

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## Bloss

I reckon I'd do what Autogenous says! Easy and will get the same result at much less cost. 20-30mm ain't all that much in the scheme of things.

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## Craigoss

What i left out is, that there is a wall seperating the extension to which I am removing to make open plan. Removing the wall will mean some roof and ceiling weight will be transfered to the pier which is sinking, so I will be replacing the old piers regardless of time and effort.

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## dib

I think maybe you should check to see what footings are currently there.  I had an engineer "design" pier footings for an extension in Cardiff and they where a bit shallower - 500mm from memory.  There were some piers in the old section that had sunk enough to cause an office chair with me sitting in it to roll away.  I just packed them up - adding a bit of packing every 40 years in my opinion is no biggy. 
Personally, I would try to keep the outside piers the same if you can.  I would pack as needed except for the pier with extra weight, which I would check / put a better footing at the right height to use the existing pier and put that back in ( if possible)

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