Forum

Replies

• 

  Simon Smith July 1, 2012 at 12:48pm

  Firstly natural stone needs to be layed on a full mortar bed not just sand, no wonder he butt jointed them as the pointing would have cracked due to the flexible bedding.

  For longevity the whole lot should be lifted and re-layed by someone who knows what they are doing as simply trying to point this will not work due to the pointing contantly cracking because of the flexible bed.

  Also you need at very least a 5mm joint for slurry resin pointing, better with closer to 8mm. If you do decide to try and repoint without lifting (which is very likely to fail) then you'd need to grind out the joints to at least 8mm wide. This will be incredibly time consuming and very difficult to do without destroying the stone.

  If you are sure the bed is only screeded sand not a lean mortar then In my opinion the only option is to lift and relay.

  Such a shame on what i assume is an expensive high end product.
• 

  Matt - Allscape SW July 1, 2012 at 1:07pm

  Thanks for replying Simon.

  I think that I am going to suggest to the client that I lift one of the slabs at the edge of the patio to ascertain what the bedding layer is.  I'm hoping that it is a mortar bed, but there has definitely been movement and even if it is I am going to have a problem trying to retrospectively point it up as some of the joints are really tight as it's been butt jointed.

  I'm in a difficult situation with this because I knew the guy who laid the patio and although he has closed his business and gone to work for one of the big national paving companies, he was very good at what he did... or at least I thought he was.  He was one of the biggest paving guys down here in cornwall anyway so this patio has shocked me.  If it was laid on a full mortar bed, surely it should also have been pointed to prevent this type of weed problem occurring?  I know that my client paid tens of thousands for this patio and he is, understandably quite miffed at the moment.

  Luckily I have at least managed to stop the client from drenching the whole lot in roundup!
• 

  Steve London Stone July 1, 2012 at 1:07pm

  Agree with Simon all the way.  If its laid on sand, it is doomed to fail and the only way to fix it is to lift and relay. 

  Because its laid on sand then the paving is not stable and if any re-pointing will be loose and cracking within a few months.

  On the bright side because its been laid on sand it will be much easier to lift without damaging the stone.  The contractor sounds like a complete cowboy, the sand screed aside, an experienced contractor should know that natural stone should not be butt jointed
• 

  Matt - Allscape SW July 11, 2012 at 10:09pm

  Quick up date on this problem.  I have lifted 3 separate slabs in different locations on the patio.  The good news is it has been laid on a mortar bed, the bad news is that all 3 slabs that I lifted firstly came up very easily and secondly had significant voids in the bedding layer.  I have also ascertained that when the paving was laid it was then 'pointed' with a red kiln sand which was just brushed into the joints.

  I have advised the client to go to Brett paving to see if they have any form of comeback as the installer was Brett approved.  Does anyone know if Brett Paving would cover repairs to work carried out by an approved installer that has ceased trading?
• 

  Colin Hunt July 12, 2012 at 5:13pm

  It's an all or nothing decision with no half measures as far as I am concerned.  The paving needs to be taken up, the ground excavated, a suitable base(I would go concrete) laid, the slabs bedded on a full bed then pointed.
• PRO

  Graham Parker July 14, 2012 at 11:18am

  I would echo the guys above but also add that as the paving has been laid incorrectly the base will also need to be checked as this may also be unsuitable.

  I am not sure if Bretts have the same sort of cover as say Marshalls. Had it been a Marshalls registered contractor then Marshalls would of picked up the tab and arranged for it to of been relaid.

  I therefore suggest you get the customer to check with Bretts as to what there guarantees if any are.
• 

  David P Fisher July 14, 2012 at 4:14pm

  Further confirmation here.

  We have just had to lift and relay about 230m2 paving ( laid by builders 4-5 years ago). Our original job was to  pressure wash and repoint but as we got into the job the slabs cleaned up well and the remaining pointing came straight out but we  found that 95% of slabs were loose. When lifted  the slabs had been laid on blobs (some were 100mm tall) and there was a world of wildlife living beneath. It was also obvious that the pointing had been mixed dry and swept in.  Fortunately most of the slabs came up clean, all the blobs were removed from site and the base levels re-adjusted. The paving has been relaid on a full bed and each the back of eack slab was soaked before laying. The pointing is now well underway and the cutomer is smiling again despite the knowledge of a hefty bill on the way.

   
• 

  Matt - Allscape SW July 14, 2012 at 7:07pm

  Firstly, thank you for your comments guys.  Although I am certain it is not what the client is going to want to hear I am in agreement with everyone on here who is saying that to guarantee longevity the whole lot should be taken up, the base checked and rectified if necessary and then the paving relaid on a full bed and pointed correctly.

  The client is going to speak to Brett Paving this coming week to try and ascertain if his guarantee covers the patio having to be lifted and relaid.  I was in at the property last week cutting hedges and I investigated the paving a little more.  There appears to have been some significant movement in the retaining walls as there are some sizeable cracks in the render on the top and sides of the walls.  This made me a little concerned about the integrity of the base although there is no visible signs of vertical movement in the finished level of the paving.  I did notice that some of the slabs felt loose underfoot and when I stepped on them I noticed water leaching from around the sides, further indicating voids in the bedding layer.  I should perhaps make it clear the slabs I lifted had been laid on a full mortar bed and that the only voids were ones which looked like they were made with the end of a trowel, they were over the full extent of the bed and were around 1" in depth - and full of water.

  I will be popping back this week and so will take some pictures and post them here to gain some more opinion.

  Thanks again for all your comments guys, much appreciated.
• 

  Steve London Stone July 15, 2012 at 2:35pm

  Concrete is over kill for a domestic patio.  MOT type 1 will be more than adequate.  We sell a lot of sawn sandstones and we have often found when concrete bases are used that moisture patches appear through the stone.  I think it is because the moisture from the mortar mix has nowhere to escape so it goes through the easiest route, which is the stone.
  
  Colin Hunt said:

  It's an all or nothing decision with no half measures as far as I am concerned.  The paving needs to be taken up, the ground excavated, a suitable base(I would go concrete) laid, the slabs bedded on a full bed then pointed.
• 

  Colin Hunt July 15, 2012 at 8:15pm

  Old habits die hard!  I've always worked on the basis that once a job is done it's done and is going to last the client 20 - 30  or more years - hence the concrete base.  Not done us too bad as through recommendation, we are now working for children and even grandchildren of some of our first customers of 30 years or so ago. 

  Having said that, because of cost, we have used Type 1 with sand/cement bedding, but will it still be stable in 30years time...............you tell me?!
  
  London Stone said:

  Concrete is over kill for a domestic patio.  MOT type 1 will be more than adequate.  We sell a lot of sawn sandstones and we have often found when concrete bases are used that moisture patches appear through the stone.  I think it is because the moisture from the mortar mix has nowhere to escape so it goes through the easiest route, which is the stone.
  
  Colin Hunt said:

  It's an all or nothing decision with no half measures as far as I am concerned.  The paving needs to be taken up, the ground excavated, a suitable base(I would go concrete) laid, the slabs bedded on a full bed then pointed.