The Brew Cabin

I have at present I have a patio that I laid myself last April and am now keen to take it up along with the pathway and re-design it all and then re-lay it. There are a few things I would like advice on though please :-

1) Can you suggest the easiest way to lift the old slabs up so they do not break as I am looking to use them
again ?

2) Will there be any issues in my doing the above that you can see ?

3) Once they are all up , do you suggest flattening the whole lot with a wacker plate ?

4) Will it be suffice to then lay the slabs on the previous mix by just putting a fresh mix on top ?

5) What mix should I use...last time I believe I did 5:1. Is that OK ?

6) I will also be digging up some more of the grass to put down more slabs. Now should I put down a sub-base this time as I felt last I should have done especially as the ground consist of a fair bit of clay ? The current patio hasn`t suffered too much at all but I am wondering whether some of the imperfections I have experienced are due to no sub-base ?

Thanks very much in advance

Chas

Hi PNE - is that a reference to the footy club?

1 - lifting the existing paving: easiest is to use a pick, driving the point in under the flags and then levering them up.

2 - the only 'issues' of any importance are dealing with any old mortar adhering to the flags. You mention that the flags were liad on a 5:1 mix, previously. If this was a wet mortar, the flags may well have bonded to the mortar and it will need chiselling off, if the flags are to be re-used. This is best done with a bolster and lump hammer.

Any joint mortar that remaind attached to the flag edges can similarly be removed.

3 - compaction with a vibrating plate can't do any harm, but I'm not sure it would do any good if it's simply a matter of running the vib plate over old mortar.

4 - You could re-lay on fresh bedding over the old mortar bed, as long as there is no problem with DPC and levels, but see (6)

5 - There's no need for a bedding mix to have such a high cement content. 10:1 is fine - see the Laying flags page for info on my preferred bedding mix.

6 - A sub-base is not essential beneath a residential patio, but can be used if there is a problem with bad ground or with levels that required lifting.

If this were my job, I'd actually rip out the old mortar bedding and either bin it or break it up to pieces of 50mm or less and sprread it out over the whole site as what we call a 'blinding' layer. Then, if there is a need for a sub-base, lay that, compact it with the vib plate, and then re-lay the new patio, on my 10:1 semi-dry bedding mix. I would not be 100% happy laying parts of the new patio on top of old mortar (a rigid base) and part of it on a flexible sub-base, as the two parts would behave differently over time and you could end up with the dreaded differential settlement.

How's that?

Hi Tony

Firstly you are quite correct in your observation...it is a reference to the one and only Preston North End FC...!

Secondly, thanks for a quick reply and looking at your comments it has started to give me faith in my own abilty again and I might just pull this off.

Anyway just a couple more questions for you...

1) If I decide to break up the old mortar and use it for a "binding layer", will I need to use a vib plate on that or not ?

2) Will I need in your opinion to hire a "breaker" of some desciption to do it the breaking with ?

3) And if I feel I do need a sub-base after all that, what do you recommend ? and this I guess will need compacting ?

I think that is it for the moment but I have a feeling that once I start this job in earnest, I will be picking your brain again.

Well done for a gem of a site.

Cheers

Chas

I spent a lot of time working in Proud Preston about 13 years ago, and had 'digs' on St Stephens' Road, in the shadow of Deepdale itself. It's still one of my favourite towns....ooops! Cities, I mean....for a night out on the beer. :)

So, to your Q's...

1 - yes - use a plate compactor to rattle over the blinding layer. It's not essential, but, if you're going to have a plate on hire anyway (for the sub-base) you might as well make best use of it.

2 - probably not. Old mortar, even a 5:1 mix isn't terribly hard stuff and breaks up with a few thwacks from a pick and/or a sledgehammer.

3 - For a patio, you can use whatever is easiest to get hold of. That might be DTp1 from a local BM or "Crusher Run" from one of the DIY sheds, or cruushed concrete, 'ballast', 'scalpings' or whatever else is on offer. As long as its a good mix of fines and lumps, and compacts well with the vib plate, it'll do for a patio.

For driveways, I don't believe in spoiling the ship for a ha'p'orth of tar, and always recommend genuine DTp1, but for patios, almost any crushed aggregate will do.

Let us know how you get on, and take photies as you go. The feedback I get tells me that folk love gawping at other folks' DIY efforts! :)

Thanks again Tony

and I sure will sent some photos as it progresses.

Watch this space

Cheers

Chas

Hi Tony

Sorry to bother you again sooner than I thought but there are just a couple more things I need to ask :-

1) I forgot to say that under part of the path that I am taking up and then breaking up the old mortar , there is an electricity cable that runs from the house and into the garage. Now will this be a problem if I start breaking up the old mortar i.e I could go through the cable ?

2) Also where part of the original path/patio was laid ( which was done by the builders and not me ) they have taken part of the patio right up to the house and in the other part there is a 4 inch gap filled with gravel between the house and the slabs which coincidentally is around the same place as the electricity cable comes out from the house. Again would this have been done for a reason or will it still be OK to put the new patio right up to the house at this point like the other bit of the patio ?

Hopefully that will be it for a while

Thanks in advance

1 - not if you're careful. It should be an armoured cable, and, if you can verify that it is, indeed, an armoured cable, and you know, more or less, just where it is, you can work carefully in that area. Consider re-laying the cable in a duct - it makes life much simpler, and safer!

2 - the mystery gap between the house and the paving sounds like a bit of laziness. Maybe they couldn't be bothered cutting flags to fit, or maybe they couldn't be bothered knocking up a bit of grano to infill the gap, but you can safely pave right up to the house when you come to do the work. :)

Good luck!

Hi Tony

I guess this must be the longest you have waited for a reply.

With reference to our last conversation...I have finished the patio and it looks great. Sorry I didn`t send any piccies and I am unable to now as I have sold up and moved on to a new house and therefore new project.

I want to tap your knowledge about pointing/grouting primarily.


We are now living in a converted barn which has a lovely York stone path along the side of it but we now want to extend it out and along to make a patio instead.

What I would like to know is how the previous owners created the whiter lokking pointing between the slabs ?
what mix would it have been?....It would then make it easier to try and match what is already there.

I have taken a couple of shots to try and help you.Is there anyway of sending them to you?

Cheers for your time

PNE aka Chas