The Brew Cabin

Posted: **Mon Mar 19, 2012 3:28 pm**

Hi

Some years ago we had extensive patios laid in Indian Sandstone. Although we requested cement mortar joints, the contractor persuaded us that polymeric sand was the best way to point the stone. Shortly after work was finished the pointing material started to come away, it never really went hard and could easily be scraped away with a fingernail. The first time the patios were power washed most of it came out. The contractors came back are redid a test piece of the patios to see if that would hold but it didnâ€™t. We believe that part of the problem is that the concrete bedding material almost fills the joints in many places and although we pointed this out to the contractor and asked him to rake it out before the joints were pointed he didnâ€™t. Also as this is handcut Indian stone, the flags are not uniform in size and neither are the joints, some of them are very small and less than 1 cm wide. Thereafter my husband decided to rake out and mortar the joints himself.

Six years have passed and the patios are still not jointed so time to get in a professional. Just had one round and another coming Wednesday and could do with some advice please.

1. The first contractor wanted to angle grind out all the bedding mortar, not just the high points, to the bottom edge of the stone flag with a disk grinder, but as these stones donâ€™t have straight edges an angle grinder will destroy the character of the stone. He was adamant that there was no other way to do it, correct or not? (The bedding mortar, having been exposed for such a long time, is beginning to crack up naturally on the surface)
2. I had read on this site that there are now some very good Polymeric Sands that do work but he was convinced that none of them work. True or not?
3. He wouldnâ€™t guarantee that his pointing wouldnâ€™t come out as he hadnâ€™t laid the patios originally. Fair or not? He was going to use Instarmac, Ultrascape, Cempoint. He indicated that it was going to cost thousands.

Apart from the fact that they have no jointing compound the stones still look like new when they are clean and as they were laid on a very thick concrete base with a reasonable hardcore sub base they havenâ€™t moved at all. Any advice you can give us to get this work done with the minimum of damage to the stone and with a jointing compound which is unlikely to come out again would be appreciated.

Posted: **Mon Mar 19, 2012 5:28 pm**

I had to take up a few square metres of mortar very recently on a sandstone patio. I tentatively began with a 4" makita angle grinder and lost my nerve for the reasons you describe. I would say it is humanly possible but he's a better man than me if he can say for sure that hour after hour he can work with the grinder and not make a single slip!

In the end i did it the long winded way and chipped it out bit by bit with and solid flat headed screw driver and a hammer. A mortar rake wouldn't touch it and I felt it would scratch the stone irrecoverably also if I carried on with it!

Posted: **Mon Mar 19, 2012 5:35 pm**

What i would do,

If flags are stuck solid then grind out the jointing (it is possible the blade is only a few mm wide), carefully chip out with plugging chisel, sweep off and hover out joints. Re-lay any loose slabs an Jet wash the lot.

Re-joint with either easi point or gftk two part resin.

Job done.

And yes, sounds like you have a big area "extensive", so it will probably cost thousands.

Posted: **Mon Mar 19, 2012 5:37 pm**

Another thing...ive done a few jobs like this where the jointing has failed and everytime the flags tend come loose whilst trying to remove the defective jointing and it has always ended up in a complete lift and relay!

Posted: **Mon Mar 19, 2012 5:49 pm**

that's what happened to me! Only about 30% of the area I chipped out came loose though thankfully!

Posted: **Mon Mar 19, 2012 7:55 pm**

I recently was asked to re-point a large patio (80sqm or so) that i had orignally priced to lay.
The customer went for a cheaper price, but regretted it in the end!
The guy was so under budget, he left a lad there who mixed the pointing up as he went in a bucket.
I allowed two days for two to rake out the old pointing, mix up and gun in easipoint, and it cost him a grand including vat and materials.
there is no cheap alternative to this problem

Posted: **Mon Mar 19, 2012 10:52 pm**

Ive yet to have a recall on pointing. Grind it out and redo the proper way, the way its been done for the last 60 years. Sand and cement. Bloody rip off products.

I may well challenge them all to send me a sample that i can put down with everyone elses product and see how they do over the years, i bet they would all decline

Posted: **Tue Mar 20, 2012 3:12 am**

Thanks for your replies, Iâ€™ll be a bit better informed now for the next contractor who is quoting for the job. I think the plugging chisel is going to be the favoured tool in the absence of anything better. As Forestboy says, I don't think anyone could work for hours with an angle grinder and not make a slip or two. I was hoping that there might be some magical power tool which was less likely to damage the stone.

The contractor didnâ€™t promise he wouldnâ€™t damage the stone just said there was no option! I got the distinct impression that we were just going to have to put up with the damage!

If the small amount of jointing compound which is left and the bedding concrete which is too high is raked out down to a depth of 2.5cm minimum, (if thatâ€™s deep enough?), then itâ€™s only about 20- 25% approximately, of the patios which will need raking. The jointing compound can be removed with very little effort, itâ€™s the bedding concrete which is a bit hard. Most of the joints are completely empty and have a good depth. Still a big job though but after today I think it's going to be hard to find a contractor who will do it manually. I did suspect it was going to cost quite a lot and donâ€™t mind paying a fair price for a good job but I would expect some kind of guarantee, is that unreasonable?

Hope the stones donâ€™t come up when theyâ€™re raked out. They seem pretty firmly fixed down at the moment.

The only reason we opted for the polymeric sand is because it doesnâ€™t stain the stone which is always a possibility with ordinary mortar. Does the easipoint or gftk stain, how does that go in, wet or dry?

Posted: **Tue Mar 20, 2012 7:16 am**

a plugging chisel will be a lot slower and more prone to problems than a grinder
for any pointing you need twice the width of the joint for the depth
I would grind a joint say 30mm deep then use a carpenters chisel to chip the sides in
then hoover out with a henry hoover
i have used ultrascape and easipoint and i believe easipoint has a slightly better range of colours
with all these rough edges how is it going to be pointed?
a picture would be handy
LLL

Posted: **Tue Mar 20, 2012 12:59 pm**

^This makes sense that you could do the initial cut through the middle of most of the not too thin joints with a grinder and then do the finish with a pluggin chisel. Still a long, labourious job though. i would guess that even by this method 1 person could only cover 10 to 20 metres a day and that's just the removal.

No doubt about it, it's an expensive fix!

Posted: **Tue Mar 20, 2012 1:02 pm**

Just worried that a grinder in the hands of someone we don't know has the potential to be disastrous. I was hoping that the contractor would fill me with confidence about how to sort it all out but he had the opposite effect. Not sure how it is going to be pointed, the last guy said that he was going to use Ultrascape Cempoint and trowel it in.

I've taken some photos but can't find out how to upload them. Can you point me in the right direction? Thanks

Posted: **Tue Mar 20, 2012 1:17 pm**

you need to upload them to something like photobucket and then view the thumbtag of the image you want cursor down to direct link, click on this and it will copy and then go back to your page and click image, a box will appear just delete what's in the box and paste what you have copied and ok it and it will appear when you post your message!

Posted: **Tue Mar 20, 2012 5:45 pm**

I could use a 100mm grinder all day and not slip, any competent person could i reckon.

Posted: **Tue Mar 20, 2012 11:34 pm**

[quote]you need to upload them to something like photobucket and then view the thumbtag of the image you want cursor down to direct link, click on this and it will copy and then go back to your page and click image, a box will appear just delete what's in the box and paste what you have copied and ok it and it will appear when you post your message!

I followed these instructions but I get a message saying that you can't use this file extension on this site when I try and post it. I can't find any instructions in the help files on this site. any ideas what I'm doing wrong?

Posted: **Wed Mar 21, 2012 7:25 am**

DNgroundworks wrote:I could use a 100mm grinder all day and not slip, any competent person could i reckon.

I agree with Dan. Its not hard to grind out joints without mullering the edges of stone. Dare I say that even if you nicked the edges of a couple of stones, its not going to be the end of the world

The Brew Cabin

Re-pointing - Without destroying stone& best material