# Forum Home Renovation Concreting  Fencing over a concrete surface

## Dave_KB

I am about to move house and the place we have bought needs a couple of short sections of fence built to close in the back garden. 
On either side of the house 2 new sections of fence are required between the house and the existing boundary fences. 
At this stage I'm thinking of using colorbond post and rail or maybe goodneighbour panels + a couple of gates. 
One side is all garden bed so that should be easy to do the posts as I have a post hole digger, but the other side is completely covered in concrete from the house to the boundary. 
My question is, usually how would the posts be installed?  I have an angle grinder + power saw and an assortment of reasonably long masonry drill bits...but knocking (3 to 4) holes in the concrete using these maybe pretty painful.  Would a jackhammer be the best option? 
Or would I be better off outsourcing this part of the job to a concrete cutting mob...if they do this sort of thing?

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## DJ's Timber

I would imagine that you'd bolt the posts to the concrete, not dig holes through it

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## malb

How short is short? 
If the gap between the house and boundary fence that you wish to close is under 2350mm, you should be able to mount the fence end on an existing fence post, the house end to the house wall, and cut down the panels and top/bottom rails to suit. 
If you need longer, I would take the same approach and have a metalworker weld some base flanges to 50 x 50 x 3mm tube of suitable length, then have these powdercoated to match the panels or rails as required. The flanges can then be bolted to the concrete with dyna bolts to support intermediate posts. 
For a gate maybe a metre wide, I would be cutting an opening in the concrete at least 300mm square, (increase with gate area), digging about 600mm deep, select a 75mm x 75mm x 3mm post of suitable length, and concrete (not quickset) it into hole, filling to finish flush with the existing concrete. Allow a couple of days to set fully. You can fill the post with a drier mix of concrete to increase rigidity if you wish. The post fill mix needs enough moisture to activate the cement properly, but should not be sloppy, as the mix will then shrink as the excess water evaporates.

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