I think this was discussed recently, but -- sorry -- I cannot find the
thread, using Google Groups search.
We've had gouges out of our concrete drive for years, but this last
winter has really made them bad, and I ought to patch them
The worst of them is here: it's nearly 4" deep in the middle:
I'm thinking that I will pressure washer the crap out of them, and then
fill with a strong and fairly sloppy concrete mix, using fine gravel as
part of the the mix.
Are you supposed to line the hole with PVA solution as well? I'm never
too sure why you do this exactly, though people commonly say "it's what
you do". If so, what sort of solution to be used?
others may priovide chapter and verse but I think that unfortunately
you are on a loser here - looks like frost/salt damage spalling the
surface - IME whatever you try and "spread" on top will fail after a
winter or two starting at the (thin) edges and then once the water can
settle in the cracks and freeze..... back to square 1 PDQ.
Could look at costs of tarmacing over it (by a *reputable* firm)??
I think you ought to replace the drive and not use whoever laid that one
to do it. Patches only work if the substrate they are being applied to
is substantially sound.
That looks to me as though the concrete was badly laid to begin with and
has been deteriorating ever since.
> I'm thinking that I will pressure washer the crap out of them, and then
> fill with a strong and fairly sloppy concrete mix, using fine gravel as
> part of the the mix....
Strong and sloppy are mutally exclusive terms when mixing concrete. Too
much water produces a weak concrete, which may even be the problem with
the original drive.
You should not have more than 550ml of water per kg of cement, which
includes any water in the sand. At that ratio, you should be able to
move it by shovel without much falling off as you lift it.
If the concrete looked sound, I would go with the patch, but that has to
be one of the worst bits of concrete I have seen since a chap I knew
laid his garden path by pouring it as a runny mix from the top of a hill.
No - PVA is worthless in a very damp/wet environment.
What you should do and has always worked for me, is to mix up some cement
slurry (cement + water) to the consistency of honey and paint that all over
the inside of the patch to be repaired. Wet the hole first of dry.
Apply concrete asap and the slurry will ensure a very tight bond between the
old and new.
The rest of your idea seems fine - what I'd do.
The concrete has been improperly laid. Probably someone has played
about with it too much when it was wet and drawn the cement to the
surface to the detriment of a few inches below where voids have been
left. (ie short of cement and fine particals). Water & frost soon
All you can do is chisel out any loose material and try a repair with
a 3:1 mix of sand & cement. Try to avoid any feather edges by
chiseling out a definate edge to your repairs. Obviously lean out
all muck and loose material.
You need to leave it undisturbed for a couple of weeks this weather.
Don't do if frost or rain expected & cover it up withan insulating
It will look a mess but there's no help for it.
Its only saving grace is it does not appear to have moved or cracked
right through. Which suggests its sub base is ok.
Could you tolerate a rise in level of say 40mm? If so, one option would
be treat it as a sub base, shutter round the edge, and pour a new sharp
sand and cement screed as a fairly strong mix over the lot, and then
tamp it off neatly. That would give a much nicer appearance that a patch
job, and also not leave any feathered edges to lift and allow water in.
| Internode Ltd - http://www.internode.co.uk |
| John Rumm - john(at)internode(dot)co(dot)uk |
Piccies please :)
Concrete isn't strong in thin sections. Cut the bad bits into square
sided areas with a large angle grinder.
I tend to use Hanson Instant Concrete from B&Q. Basically put in dry &
watered - dead easy & very strong.
5-1 PVA acts as a bonding agent.
Dave - The Medway Handyman www.medwayhandyman.co.uk
OP here... Tabby/NT:
> Piccies please :)
Er -- I put links in my post:
(BTW: sorry for all the really awful pop-up ads you get on tinypic ...!)
Thanks everyone! I never realised we had such CRAP concrete! :-) We've
been here 25 years, and the drive was spalling when we arrived. The
holes have got steadily worse, but the last winter was a "tipping
ISTR that the chap we bought the house from said that he'd had the drive
skimmed -- probably (I see now) because of the problem people have
So: at least now I know the extent of my problem. I may even do what
JimK suggested right off: get a [good] tarmac company in. (I've always
fancied tarmac: I love to see the rain steaming off it when the sun
My main problem is that I have a pathological inability to spend large
sums of money... especially now that I'm not working. However I think
tarmaccing is beyond DIY, and I suspect re-laying the concrete is now
also beyond DIY.
OK ... I'm thinking....! Thank you very much, chaps for your very
I think he was after pics of the 'pouring it as a runny mix from the top of
Maybe an outdoor levelling compound?
No, just a very incompetent, but enthusiastic, DIYer - the sort you
really don't want to buy a house from.
I wish I did have photos. It never occurred to him that a runny mix
would nearly all run to the bottom of the hill.
Sounds like the old joke about a chap being given a set of water skis,
and then spending ages looking for a lake on a hill.
Lol. Shame about the lack of pics :)
This is surely the best option. If its too costly in current
circumstances, patching it shuold at least last a few years. I dont
know whether painting the surface with cement/water slurry would
toughen it to some extent.
Well one of the regulars down at the local was aked by his wife to put the
fishpond on a slope so that see could watch the fish from the house.