Patching the holes in a concrete drive

[Another John]

Hi all

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:

'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?

Cheers John

[Nightjar]

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.

has been deteriorating ever since.

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.

Colin Bignell

[SS]

I would patch them and see how it goes if that doesnt work then move on to other options. I patched some (another country,frost free) and some were no more than an inch deep. Used diluted PVA first and they have held for 3 years now. For all it would cost to try and patch its worth a go.

[Nightjar]

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.

Colin Bignell

[Tim Watts]

Another John ( [e-mail]) wibbled on Friday 25 February 2011 13:12:

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.

[John Rumm]

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.

[Tabby]

Piccies please :)

NT

[The Medway Handyman]

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.

[Another John]

OP here... Tabby/NT:

Er -- I put links in my post:

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 point".

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 mentioned.

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 comes out!)

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 useful comments.

John

[zaax]

I think he was after pics of the 'pouring it as a runny mix from the top of a hill'.

Maybe an outdoor levelling compound?

[zaax]

I think he was after pics of the 'pouring it as a runny mix from the top of a hill'.

Maybe an outdoor levelling compound?

[Nightjar]

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.

Colin Bignell

[John Rumm]

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.

[Tabby]

Lol. Shame about the lack of pics :)

NT

[Tabby]

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.

NT

[ARWadsworth]

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.