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Posted: Fri Apr 18, 2008 2:23 pm
by jrob
I have about 18inch under ground, there was too much concrete below to dig deeper, there is a slight bit of movement on the 5 ft post above, with a five foot panel, all concreted in
not sure if its just a bit of flex in the post as the bottom nr to ground is solid
do posts have a bit of movement?
whats the best method to break up concrete below ground?
with making the hole too big
cheers
Posted: Fri Apr 18, 2008 3:02 pm
by MRA
To remove the concrete, your best bet would be using a Concrete Breaker. A 110v or 230v would be fine for this if the power behind the breaker is adequate (Get these from a Hire Shop). Remember, the concrete is effectively wedged in by the surrounding soil, so a decent breaker is advisable. It is worth removing because if you have 1.5m posts, a deeper hole would aid stability in the post; and if using timber posts, use 100mm over 75mm (the posts take a battering as the pressure from a 1.5m panel either side of the post in strong winds is pretty high).
A 75mm post equates to 0.0056m2, whereas a 100mm post equals 0.1m2; a significant increase in strength.
The posts mostly go at the base of the post where it meets the ground due to water ingression, so even with pressure treated timber, give them a good coat of protection.
Posted: Fri Apr 18, 2008 3:33 pm
by yourgardenworks.co.uk
Just too add to what MRA said you should look to make the holes as small as possible so as to use less concrete and a 10 - 11 kg breaker should be ample to break out the existing concrete.
Posted: Fri Apr 18, 2008 11:33 pm
by Bob_A
jrob wrote:not sure if its just a bit of flex in the post as the bottom nr to ground is solid
do posts have a bit of movement?
Does he have to dig out the post.
Could it be that a slight flexing of the post is normal?
Don't know the answer myself but if the post flexes slightly but the concrete around it stays solid in the ground then wouldn't that be ok?
Personally I'd leave for a while and see how it goes before ripping it out.
Posted: Sat Apr 19, 2008 7:06 am
by seanandruby
Why is there concrete below? Be careful its not covering any services before you start breking it out.
Posted: Sat Apr 19, 2008 4:21 pm
by lutonlagerlout
sounds like a foul run to me perhaps
wooden posts flex slightly,concrete not
LLL
Posted: Tue Apr 22, 2008 12:40 am
by matt h
Could employ wooden hardwood wedges to stiffen the posts if in concrete surround without digging up. timber may have shrunk in the concrete base.. Is this your own place or are you doin it for someone else?:)