Hi all Hopefully at the weekend I will be putting up a few 7 foot, concrete posts, 12" gravel boards, 4 foot panels I know this question has been asked\answered a thousand times and generates almost as many variations but just want a simple clarification please......If possible ! Decided against using Postcrete - seems pricy for a bit of sand and cement but realise you're paying for convenience (plus I guess a whole lot of expensive additives) Seems 2nd easiest option is "all in ballast" and add cement in a 5 - 1 ratio. Add water but keep a dryish, stiff mix Will dig down 2 feet, drop in posts, level, prop with some hardcore, concrete, tamp down, check levels, drop in panels, prop if needed with some timber All sound ok guys ? Any need for adding plasticiser to the mix ? I guess not Also no clear verdict on a dry mix then either leave overnight or sprinkle with water or just adding the water before chucking in the hole Would appreciate your thoughts as ever PS - Will also sort out my gate over the w/end using the concrete screws as recommended recently - thanks
if you've got a quarry close they'll probably do a ready mix - just add cement/water to suit - it'll cost next to nothing if you can collect - or a ton bag from a merchants your plan sounds OK - there's a 100 ways to do this - nice sloppy mix, not dry - treat yourself to a MiniMix
Having done fencing for more then 30 years, I will tell you the only way to do it , all in ballast mix at 6.1, NO water at all, the moisture from the ballast is enough. As you say 2' deep hole, but only about 2"/3" wider then the post on all side, put a couple of inches of the concrete in the bottom of the hole, post in then start filling with the concrete every 6" compact the concrete down really well ( I have a proper fencing Graffter) but a sturdy piece of 2" x 2" timber will do, if you have done it right you will have trouble moving the post straight away.
Cheers Sean Was planning on getting sacks of ballast from B&Q as near to me, with a discount about 1.40 a sack so cheap When you say a ready mix from a quarry - just add cement\water.........That's what I was planning on doing with the above anyway From my understanding (may be not quite right) the ballast is an "all in" mix - so contains aggregate and sand, then I'm adding cement and water so this equals concrete 5-1 ratio sounds about right to you Sean ? Plasticiser Y / N ? And you say a nice sloppy mix then.......I just though that a stiff mix would support the posts better whilst setting As we both said, loads of ways around this and I guess that if you do this on a regular basis, then you will have your own, preferred method, tried and tested
yep just add cement/water - we call it consand up here ratio sounds fine - doesn't need to be accurate, no point adding anything other than water and cement sloppy mix will run and fill any little voids - don't bother trying to dig a nice tidy regular shaped hole
Thanks Phil for sharing your 30 years + of knowledge - much appreciated Have borrowed a decent (trenching I think it's called) spade from my brother. I gave him a hand last year building his decking and we both agreed that my post holes were superb, neat and tidy with vertical sides and not over large. So I've had a bit of practice ! Ok so a 6-1 mix and no water. Seen the sacks of ballast at the weekend and although stored inside B&Q, noticed how wet the mix was, plus I guess the ground is damp this time of the year Yep will tamp down the concrete, got some spare timber posts that I can use Have been reading up on this and having trouble deciding which method to go for, ie dry mix (Phil) versus wet mix (Sean) Is it just down to personal preference or is there a more scientific reason for dry / wet mix (don't want to start another debate like the current PVA saga on the plastering thread)
With a dry mix you can put the fence up as you go, ie: post in, gravel board, panel, post and so on, with a wet mix you will have a post that may aswell be set in jelly, you will end up with bracing bits of timber all over the place. One thing to remember is that the concrete isn't holding the post in the ground, the depth is doing that, you could in theory just fill the hole with ballast and it would hold, but over the course of time it would wash away with rain fall, so the cement is just to bind it, putting it in dry it will take on moisture from the ground and set firm enough to stop it washing away.
if it's a proper trenching spade you'll not find it much use - see if you can borrow a set of spoons my wet mix argument would be that you have control of the moisture content
[quote="Sean_ork, my wet mix argument would be that you have control of the moisture content[/quote] Sean for what purpose, this isn't concrete that has any bearing on strength or load. its a fence post.
we build strong round these parts ......... or it'll blow away do what Phil says Mr D (but only because he's bigger than me)
The spade is "like" this one......http://www.screwfix.com/p/spear-jackson-newcastle-all-steel-drainer-16/38521 My brother got it for digging post holes, really nice to use, long but slim blade so the holes don't end up too large and sharp Yeah those spoons look good Sean, can always hire a set for the weekend but will probably just dig then scoop out by hand, dig, scoop, etc That's the difference when your doing work for yourself, time versus money isn't the deciding factor so if things take a little longer, then you just drink more cups of coffee during the day I to was thinking that a dry mix (although I was going to add a little water) would support the posts better whilst setting and less props, also lets you complete the fence as you go But.... the more you read up (dam internet) some peeps say the dry mix doesn't always cure fully, you get pockets of sandy material amongst set concrete, may not be enough moisture in the material and ground, etc. So for a diyer like me, its sometimes really hard to make an informed decision and have the confidence to go ahead with it - too many conflicting methods quote="Sean_ork, my wet mix argument would be that you have control of the moisture content[/quote] As for the above, would it help if I PVA'd the surrounding soil first.........................................Only joking.....................
As for the above, would it help if I PVA'd the surrounding soil first.........................................Only joking.....................[/quote] Dry pockets will not make the slightest difference, though I haven't seen any on fencing I've replace, as I said above depth is holding the post. Your spade will be ok for digging, though the angle of the handle may get in the way when compacting the concrete. I use and own one of these. http://www.amazon.co.uk/gp/aw/d/B0044TPTKO
Just stumbled upon this thread by accident, if anyone is following for advice, please, please, I implore you to ignore Phil the Pavers advice, whilst he may have been putting up fences on and off for 30 years, I have been a fencing specialist for 15 years and have read with mouth wide open in horror, Wet Mix concrete, not dry, there is a process called hydration which starts the chemical reaction to turn cement into concrete, 4/5 in 1 cement to ballast ratio, use a slump test to check you have everything mixed properly, hole should be approx 30% in ground to out of ground, 6’ post out of ground should be 2’ in ground, stand post should have approx the same width of the post surrounded each way by the same amount of concrete, 4” post should be 12” hole with post to middle, whilst your fence may not be a multi story car park, it needs strength to stop it blowing away in the wind, a 6’ wide panel is extremely weight bearing in the mildestof gusts, a gale will just push it over. If in any doubt, consult a specialist, not an odd-jobber.
This is a joke yes!!!. Use a slump test on fence post concrete. A fencing specialist. ??? While a totally dry mix might not be right, who going to the trouble of gauging the mix to the point of a slump test on a fence post.
I do a bit of fencing here and there. Mainly to get a bit fitter. I dig a hole about the right depth. I stick the post in I put some water in I pour the postmix in I put a level on the post. And repeat. None of my fences have blown down yet.