# Forum Home Renovation Sub Flooring  Drilling into concrete stumps - ok?

## djhaslett

G'day all, this is my first post. 
I'm fixing up a few plinth boards on my place, which is a weatherboard house sitting on concrete stumps. There is a small section where I need to drill into the stumps to fix a couple of bits of 4 x 2 so I can nail the plinth boards.
Someone told me once that drilling into concrete stumps is a no-no. They would only be small holes to fix a couple of screws. Does anyone have any ideas? 
Thanks, Darren.

----------


## Exador

> G'day all, this is my first post. 
> I'm fixing up a few plinth boards on my place, which is a weatherboard house sitting on concrete stumps. There is a small section where I need to drill into the stumps to fix a couple of bits of 4 x 2 so I can nail the plinth boards.
> Someone told me once that drilling into concrete stumps is a no-no. They would only be small holes to fix a couple of screws. Does anyone have any ideas? 
> Thanks, Darren.

  No prob at all Darren, except that you'll have to watch out for the reinforcing. If the post is exposed to moisture or if the hole is very low, you might want to seal it with silicone as well to prevent water getting to the reinforcement, which can get ugly pretty quickly, but if it's under your house at the top of the post, you should be fine.

----------


## djhaslett

Thanks very much for your quick reply Craig. If you don't mind me asking, are you a qualified tradesperson?

----------


## ozwinner

I wouldnt drill into a concrete stump.
Id be more inclined to clamp a block onto the stump.
Or sislatic it on.
Or make a some timber frame work that wedges between stumps. 
And before you ask, ive only been in the building trade for 30 odd years.  :Tongue:   
Al  :Biggrin:

----------


## djhaslett

Tks Oz - what type of clamp would you use? What about a bigger version of those tighenable ones you use on a radiator hose - what are they called?

----------


## Ivan in Oz

> And before you ask, ive only been in the building trade for 30 odd years.  
> Al

  I agree with Oz on that one;
What's the worst which could happen your way:confused:  :Frown:   
I'd go CLAMP.............what's the worst etc. etc.. Blah! Blah!! Blah!!!  HOWEVER 
>Rub your left nipple on my avatar....
> All your ills will be cured.....
> Trust me...... 
Didn't work..........................:eek: ............... :Tongue:

----------


## ozwinner

> Tks Oz - what type of clamp would you use? What about a bigger version of those tighenable ones you use on a radiator hose - what are they called?

  You can get some whopping stainless hose clamps, Id be useing one of theose with some silastic as well. 
Al  :Smilie:

----------


## ozwinner

> >Rub your left nipple on my avatar....
> > All your ills will be cured.....
> > Trust me...... 
> Didn't work..........................:eek: ...............

  You only did it once didnt you??
You have to repeat the process many, many times.
Preferably after grog..... 
Al  :Biggrin:

----------


## Exador

> Thanks very much for your quick reply Craig. If you don't mind me asking, are you a qualified tradesperson?

  Used to work in geotechnics. The only real issue with drilling concrete stumps is the reduction in cover to the reo, which can lead to water ingress and eventually, spalling as the reo rusts.

----------

