Patio Laid in Sep......cracks Picture Heavy

[mark740]

Hi all,

I had a large landscaping job done in Sep-Oct this involved removal of 10 skips of earth to move a retaining wall back from my house to build a patio.

However the patio pointing has started to crack in some places, and the first 4 slabs in the path move so much they started rocking, also some of the pointing in the main patio completly cracked.

I obviously had them back to sort the really bad slabs but he said that you "will get small cracks" im not really that knowledgable on this thats why i had someone in.

Im now thinking the job has not been done properly, whats worse is this is a friends husbands company that done the work.

Here are some pictures, i just want to know if the cracking is "normal" if not what causes it etc.

This is the patio

This is a crack

same crack not so close

this is the pathway

cracks in the pathway

This is one that was re-done a week ago...!

all the slabs where laid on 100mm of compacted type1 and laid on a mortar bed.

I just want to get some better opinions on it before i decide what to do next

 

[mark740]

Can people see the pictures ?

 

[roberta1000]

Yes thanks.

IMHO it's eventually quite likely to get a few cracks in the pointing due to temperature expansion/contraction over such a length of essentially solid concrete. But these look more like drying out cracks so the mix was likely a bit strong. Hard to avoid when the pointing is done to a feather edge like that. I would just have butted the slabs and not tried to point them. Nothing much to bother about.

If some of the slabs are rocking that's a different matter and the preparation hasn't been thorough enough.

 

[mark740]

cheers

i was not sure if the pictures were showing as i used goggle instead of photo bucket.

the guy who done the work is being pretty good with it all and agreed to re-point any next year that get too bad.

i just didn't want to phone him and complain about something that is normal and make myself look a bit of a plonker

 

[ukbertie]

As a landscape Gardener i would agree about the cracks in the pointing , i to would have butted them together , if the others are rocking as bad as you say then i would sujest that the type 1 is either not thick enough or has not been compacted to a desired level,Ask the contracto if he spotted the slabs or layed a them on a mortar bed

 

[mark740]

the type 1 is def 100mm + as i have before and after pictures.

I have tapped them and most seem solid the ones that came lose had 5 big splodges under them, the blobs were big though, looked less like 5 blobs and more like a bed that had been made with 5 dollops of muck.

Without lifting them im guessing he would say full bed, but im not sure my self that they are.

the slabs where from marshalls and stated on no account should they be butt jointed, I think that's why they didn't.

http://www.marshalls.co.uk/transform/_data/pdf/saxon_paving.pdf

 

[studips]

i do 2 or 3 patios every year.

any patios i do are a minimum of 100mm T1 compacted, 30mm of mortar 1:5 as a continuous bed (not dabs) and semi dry pointe (the mix is damp and you force it in and then smooth with a margin trowel.

the only time i have a slab move is if someone disturbs it, as for the pointing, it isn't right, he probably used a wet mix when he pointed and it's shrunk.

if he is back to repoint next year then he's doing the right thing.

Butt jointing is a recipe for weeds as dirt collects in the joints.

 

[mark740]

yes mine is 30mm ish mortar too, the guy who did the work was actually a trained bricklayer, they did point in with mortar exactly the same as the wall i have had built, so i am assuming a wet mix.......def was not semi dry as he put feb in it.

 

[r896neo]

If any slabs are rocking they haven't been layed properly, if the ones you lifted have been spot bedded why would the others be any different?

I would doubt that the sub-base has anything to do with it as even a badly prepared base wouldn't be settling enough to move the slabs already. It's surely just badly bedded flags here and there. If i was you i would lift any loose ones and check how they are layed and how deep. Because if some of them are this bad after a few weeks how will all of them be next year?

That said the other possibility is that someone walked on them while they were still going off messing up a few here and there. check it out for yourself and then speak to the guy and ask him how they are all layed see what he says

 

[mark740]

none of the slabs are rocking, not even when i jump on them?

i got him back to lift the 4 moving ones and they were the ones bridging the gap from the steps to the path, there was def not enough much under them, these have been redone with a full bed and now seem better.

only 2 from the main patio moved, i had him lift them and under one was a piece of random slate tile, i see this on the floor before he did the patio, he said it was from another job, i didn't think he would lay over it .
again these two were redone with fll beds as i checked, again no movement.

I think the path is where the problem is.

i have been out and i don't think its a full bed more like dollops.

 

[r896neo]

You said in your first post

and the first 4 slabs in the path move so much they started rocking

which was why i refered to rocking slabs.

Anyway, It's up to you what you do now but i would ask him were they laid on spots or a full bed and then if he says full bed then lift a few and if they are spot bedded tell him that you expect him to lift and re-lay them with a full bed as he himself said they should be.

 

[mark740]

I did say that yes, but i then wrote under in in my next section

I obviously had them back to sort the really bad slabs

which was the 4 slabs that were rocking, if you look at the picture of the pathway, it was the first for that moved,the picture i have put there is after the repair.

he fixed the moving ones, but when i ask about the small cracks everywhere else he said it was normal.

i wanted to know if it was or not

so if he has laid them on spots instead of full bed, would this cause the cracking?
If it turned out it was 5 spot bedded and not full bed, is 5 spot bedding the slabs recognised as a bodge in the trade or would it be a matter of opinion as to whether it is a proper job or not?

 

[studips]

5 dabs is not ideal, it is a cheaper, quicker option, but bodge is going a little too far - it allows ants to nest, it makes it more awkward to point, the slabs are not as well supported (not so much of an issue with a quality slab), it is more likely that the slabs can move over time - as a continuous bed offers more support.

take it he did not specify how he was going to lay the slabs- you know, 'minimum 100mm compacted type 1 on a 1:4 5 dab bed of mortat, slabs to be hand pointed with a wet mix of 1:4 cement and soft sand.....etc'

if the rest of the slabs remain stable before he comes back then fair enough, but it is not how i would do it unless my customer requested that method - TO SAVE MONEY i wouldn't blame slab movement on the cracking of the pointing, that is more likely down to drying and shrinking

 

[mark740]

no it was not specified exactly how it would be done.

Unfortunately it was done by someone we know business partner of whom i trusted.

He did tell me it would be 100+mm of compacted type 1 sub base(which it def is as i see before and after and have pictures of it).
he also said the would be laid on a bed of muck (no specification as to if it was full or spots) and hand pointed, im certain he pointed it with the same mix as the walls, would this be 4.1 mix ?

i never asked for anything to save money i always said id rather pay bit more and have a proper job.

cheers for the helpful advise though guys

The majority of it has no cracks and is fine, its just 2 small bits on the main bit, and the photos i have put of the path.

the path seems to be the main concern

 

[cannyfradock]

just another opinion......

I always use a full bed of mortar when laying patio slabs, but I wouldn't condemn brickies that use dabs on a large patio area. The only problem with this is it causes big voids especially directly under where the slabs are to be pointed. When the jointing is done, these voids must be totally filled by cramming a 4:1 semi-dry mix into the joint (I use a cut down trowel which is narrow enough to fit in the joint....or a piece of roof slate) then compressing and striking off with either a flat or bucket handle jointer.

The path is different as it MUST have a full bed of mortar under the slab, so as the jointing mix has something to adhere to. Any voids to the edge of the path will always stay as voids as soil/grass will never hold a jointing compound in place.

These are only my thoughts.......Terry