[?]Concrete fence post repair - is there a suitable filler?

[Dave Chapman]

I have a concrete fence post which has cracked, although at the moment it still supports the fence, see the two pictures at:-

and...

Digging out the post to completely replace it will be a real pain since it is set in a concrete base so I was wondering if there is a suitable filler that I can purchase and then 'pour' into the cracks to reinforce the post and prevent further crumbling.

Any thoughts/suggestions will be much appreciated.

TIA - Dave.

[Onetap]

You can get an epoxy-based repair mortar, probably Screwfix or similar. Never used it. ISTR that epoxy-based flooring required careful preparation of the old screed to ensure it stayed stuck. I suspect it'd cost more than a new post and I doubt that it will stay repaired for long. But you know that. Best of luck with it.

[Tim Watts]

Sorry - it's buggered. No amount of "repair" will help there sadly..

[JimK]

Jim K

[Ian Jackson]

Alternatively mix some cement powder with ordinary resin?

I think I'd first fill the cracks and gaps in the sides of the post (and against the fencepost) with grey car repair paste - fairly stiff, so it doesn't penetrate too far, then pour resin in from the top. In parts, you could temporarily glue on some cardboard 'shuttering'*.

You may have to use a little cunning to avoid too much resin oozing out on the fence post side. Maybe you could first prepare some resin with a lot of hardener in it (so it goes off quickly), and then dribble that down on the post side only. As it starts to harden, keep topping it up.

• I think that's the correct description.

If you make a decent job of it, the post will probably long outlast the fence!

[RobertL]

What about 'cementitious grout' - the kind of thing you pour on concrete so that it flows flows under steelwork bases. You'd need to make a sort of wooden mould around the post an then pour it in. it's quite runny so it wo uld spread into the cracks a bit.

Robert

[Lee]

What the others said, although a couple of those large metal "cable ties" (road sign type) wrapped around it might just about keep it in one piece for a while longer.

[Martin Brown]

You might be able to extend its life slightly by either epoxy filler or the cheaper alternative of slightly expanding high tack polyurethane glue in the gaps. Basically whatever you do the rusting process will continue and widen the gap probably sooner rather than later.

[dennis]

That can't be true, they have repaired bridge supports with similar problems.

It needs a new post casting around the old one.

Easier to dig it out.

[Tim Watts]

Buggered in any meaningful way... It's not supporting a bridge - the cost of removal is tiny compared to the cost of removal of a broken bridge column with a bridge on top...

yep...

[Peter Parry]

Not really, the post is cracking because the vertical iron reinforcing bar is rusting along its length (as it seems are the horizontal bolts fixing the fence). When Iron turns to Rust (Iron oxide) it expands and this cracks the concrete. You can't keep out the water as the bar has probably now corroded to its base so it will continue to expand and crack any repair no matter what you plaster on top. The strength of the post is in the iron bar, not the concrete.

[The Medway Handyman]

Yup! Buggered!

[Capitol]

Easy. Crack the concrete away from the iron bits, you don't need to go much lower than the bottom bolt. It will ideally look a bit castellated and give a good key. Give the iron a thin coat of bitumen and cast a new post in situ but 2 inches taller to cover the iron. You only need to shutter 3 sides and there's enough iron around to give adequate strength. Some neat cement on the join with the original post will probably help, as will a coat of bitumen on the top of the rebuilt post.

[Rick Hughes]

To repair with resin and expect it to be strong ... I think not unless you grind out cracks to provide clean surface. If it were me (and I didn't want to replace) I'd fill with resin bolt fix material (something like Fischer Polyester Styrene-Free Resin) , then bolt on a support strap of 9mm thick galv steel on the face that takes most of tension forces ... fixing strap with resin bolts to avoiding bursting by expanding bolts.

[harryagain]

It has cracked because there is insufficient concrete cover over the reinforcing.

50mm is the min. cover to prevent this happening. It doesn't rust (when properly covered @50mm) due to the alkalinity of the concrete. When not properly covered, acidic rainwater causes the reinforcing to rust, the swelling effect shatters the concrete. It is buggered and can't be fixed.

The above about bitumen is drivel. Concrete bonds to steel, that is what gives reinforced concrete it's strength.

[Andrew Mawson]

+1

With a Kango it's an hours work to chop out the old, open up a socket in the slab, slip in the new and bed it with concrete. Any 'repair' to that post will be a waste of time and money

Andrew

[stuart noble]

Why styrene free? Ordinary car body filler would suffice, or Toolstation Profil. Might need to do it again in 10 years time :-)

[John Rumm]

Its shagged, and replacement is probably the easiest solution IMHO. If you are worried about the base, you could use a metal bolt down base support instead.

Clomp it a few times with a club hammer to knock the concrete off, and use an angle grinder to cut off the rebar etc flush with the ground. Drill and fix post base to the concrete path, and drop the new post in.

[stuart noble]

Digging out 25 kgs of concrete base is indeed a pain, and what do you do with it if you do manage to get it out without breaking your back? Take it down the tip and pour in a fresh 25kgs? Yep, those bolt down bases are a godsend

[JimK]

in the act of breaking it out it will get er broken....

"hardcore" free to good home....

can you use bolt down post bases for concrete posts or just wood?

Jim K