grinding down pier footings under a slab

[Clinton1]

Well, I hope I have the right terminology??
Apologies for the long post... just trying to make sure I explain myself properly....

I want to do some paving, around the back extention (a 'built over' slab) but the pier footings under the house slab "suck".

The pier footings were not 'tidyed up' and the top of them come too far up the slab. Basically the piers were poured and the top of the concrete was not smoothed, the slab form laid over the piers and the slab poured.
Slab smoothed, formwork removed.... forget about the piers.... About 1/4 of the piers extend outside the edge of the slab, as well as up the slab.

Structurally its been approved, but looks a mess and creates a drama for the paving job.

To pave I would like to have the top of the pavers 75mm down from the top of the slab, as per the Builders "waterproofing guarantee" requirement.
If the top of the pavers is less than 75mm down, the warranty is void.

In some places the top of the pier footings is 25mm down from the slab edge.
I need to lay pavers, sandbed, concrete slab to pave 'properly'.
I don't want to consider any other paving 'style' at this point, as I've been through the pro's and con's of other paving styles and have decided on pavers over slab.

I've been advised by a Landscaper to grind the top of the pier footing down just far enough to lay pavers, and that he has sought advice from a builder (phone a mate). Says the builder reckons its fine, and no dramas.
The Landscaper is no-ones fool and is the lanscaper of choice for a lot of top builders out my way. My building plans have not been looked at.

I'm still cautious about touching my pier footings... my guts says that messing with the structural components is a quick way to stuffing up.

Grind the top of the piers down (max 125mm), or not?

[Bleedin Thumb]

125mm is cutting it a bit fine...so to speak. But all you are doing is shaving the pier square right?

Would it be possible to go back to your builder and explain what you are doing and that you want to keep your warranty but that his poor workmanship on the piers puts you in a difficult situation.... does he mind coming back and cleaning up the piers or alternatively you can do this for him if he honors the warranty...
Its worth a try, I doubt that he would have a problem.

[ozwinner]

Bit hard I know from East Timor Clinton, but could you get the missus to post you some pics so we could get a better idea of the problem.

Al

[Clinton1]

Bleeding:
The mob that did the extension have gone belly up.... a reflection of the quality of their work.

Al:
The digi camera is over here with me.... yep, a pic would be ideal!

I'm hoping to get the paving done (I play labourer to the landscaper) when I come back in April for a short break.

Yep, its just shaving down the top of the pier.... gotta shave it down using the following calculation:
"add the thickness of paver, sandbed and slab minus the 25mm of clear space"

Clear as mud right..... bloody picture would be good!

The pier footings are a column.
About 1/3 of the column is outside the slab, the rest is under the slab and I won't need to touch them.

[johnc]

Clinton,

Grinding back isn't going to effect the footprint of the footings which is half the issue, the second of course will you leave enough mass (i.e. 450mm x 450mm or whatever) to remain within regs. Pictures would be good but on the face of it if this is just overflow it should be possible to remove it without problems unless you expose some reo.

John.

[Bleedin Thumb]

What are you worried about preserving your warranty if the builder has gone belly up?

[Clinton1]

if the warranty said 'top of the pavers must be 75mm down from the damp course or waterproofing will be void" then I figure it means....
"if the top of the pavers are more than 75mm to the waterproofing you will get water in the house".

Just keeping things 'in spec', so I don't make a problem that I need to fix later on.

[ian]

Clinton
I need a pic

BUT there should be steel in your piers covered by concrete
the concrete cover "should" stop the steel coroding and spalling the piers
grinding 125mm off the piers is likely to expose the steel which will then corode which will spall the concrete in the piers = very expensive fix.

it might be that your best approach is to cut the pavers in


ian

[Clinton1]

thanks Ian.... is it possible to 'reseal' the pier when the steel is exposed?

[ian]

that's one of the reasons I need a pic

cutting 125mm off is likely to leave the steel proud of the pier, so then what do you do?
I'll admit that I'm not sure

ian