Concrete padstone

16 Jun 2018
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N.yorkshire & Cumbria
United Kingdom
Hi all. I have to cast a padstone with reinforcing onto a stone wall top to carry a steel column which supports the centre of my ridge steel.
The pad is specified as 300x300x1000.
What mix ratio should I use and do I add anything to protect the steel.
Regards kev
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Whoever specified the padstone should specify the mix. Anything else is just a guess.

Rebar is not protected, but again who ever designed this should specify the amount of cover and spacing.
Normally concrete containing rebar is an ST4 mix.

You need the structural engineer's notes on the design.
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That is a mighty big padstone; would two 152 x 152 x 30 1m lengths of steel side-by-side not do?
It will take a bit of lifting too, weighing in at around 215kg....
It seems very large. I haven't seen one bigger than 600mm long & 215mm square.
The problem with a padstone that size is that it would in practice have to be cast insitu.
With that, there's no knowing the strength of the concrete. Off-the-peg padstones are usually around 50N/mm² crushing strength,
but they are made under factory conditions where they can achieve that strength with vibrators and specific mixes etc. A DIY job is
unlikely to achieve anything like that.
If it's taking a point load from a steel column, the pressure under the baseplate is likely to be high.
Really, the SE should have designed something specific for this job with DIY skills in mind, rather than just give him something which he must know would be difficult to achieve in practice.
Last edited:
Yes the SE did specify it to be cast in situ and yes it carries the steel column that supports the centre of the steel ridge beam . It's onto a stone wall . I will give him a call and see if I could use premade instead .
I am concerned about the strength of a cast in situ job

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