The Brew Cabin

We had a patio laid using Marshalls Heritage Old Yorkstone slabs 10 days ago. The slabs have been laid on a full bed of mortar. The pointing looks crumbly, uneven and generally awful. We think it's because the builder covered everything with sharp sand, it rained heavily and the sand got into the mortar. I would like some advice on sorting this out.
How much of the pointing should be raked out and what mix should be used to repoint? Should it be a wet mix?
What's the best tool for raking out?

I need to gain some knowledge about this before negotiating with the builder. He's suggesting that no raking out is needed. This would make the level of the pointing wrong for a start.

This looks like a great website. I could really do with some help!

The old pointing needs to be cut out at least 12mm deep, preferably 20-25mm. I normally use a roofer's pick for this when the joints are fairly wide, but some may choose to use an angle grinder or a hammer and bolster.

The replacement mortar should be a 5:1 mix (Class II - see Mortars page) and a true mortar, ie, wet but not sloppy and not semi-dry.

Thanks! Looks like I'll be spending the weekend raking out pointing. Should a plasticiser be used for the mortar mix? Would silver sand provide a better colour
for pointing Old Yorkstone paving?

Also, Marshalls Keykerb was used to edge the patio. It has a lot of mortar stains, which couldn't be shifted with a power washer. Any suggestions?

Thanks again - I wish I'd consulted the website before
the work was done!

Regards

Plasticiser - yes.
Silver sand - yes, if you're using a dye to colour the mortar.

Mortar stains - as they are relatively fresh, they might weather away over a month or so, but, if they are quite bad, then brick cleaning acid is the stuff to use.

TEST IT OUT on a discrete corner first, as some acids react adversely with coloured concrete products.

Use a paint brush to paint on the acid, leave it for 10 mins or so, then wash it off. Scrubbing with a wire brush will also help, but be sure to wear goggles and gloves. Assuming the acid doesn't balls up the colouring, you might need to re-apply 3 or 4 times to shift all the staining, but allow the kerbs to dry out each time, so that you can better judge how successful each application has been.

Thanks. Some more questions : At what level below the slabs should the pointing be? At the moment it's about
quarter of an inch. Also, could you recommend a plasticiser?

Sorry if the questions are a bit simple, but I don't know any of this stuff. Since the job didn't go as expected, I want to make sure all is ok this time.

Regards

Dominic

The pointing should be flush with the paving or no more than 3mm below paving level if tooled.

Plasticiser - whatever they have in the BM - FEBmix, PLAmix, Sealomix - they're all approved products and it's not possible to say one is better than the other.

Are you re-pointing them yourself, Dominic, or bringing the contractor back?

Looks like I'll end up doing the raking out to make sure it's done properly! The contractor will do the pointing, I hope.

The patio is small - about 10 sq m. Can all the mortar be mixed in one batch, or will it dry out? Also, I clicked on the Mortars link you pointed me to - Class II seems to be 1: 3-4 , not 1:5. can you explain? Excuse my ignorance!

Regards

Tony,

Yet another query...... I'm having problems getting the contractor to do the repointing. He wants to hand over to someone else, who seems inexperienced.

Our Builder's Merchant suggested using Geofix. What is your opinion on using this for a 10 sq. m patio?

Don't suppose you know any contractors around London W3?!!


Best Wishes

Right - here we go.....

Mortar - my mistake: I meant to hit the "4" not the "5" - a class II mortar is 1:4 - sorry for the confusion.
I can't see why the contractor isn't prepared to re-point a 10 m2 patio - it would jonly take an hour - why bring in someone else?

Geo-fix - I've seen good things with it and I've seen bad, nay, bloody awful jobs with it. I need a lot of persuading to convince me Geofix is a worthwhile investment on such a small project.

Surely it's only a coincidence that the BM wants to sell you Geofix, at approximately 10 times the price of sand and cement - they wouldn't be looking to earn an extra bob or two, would they? ;)

Contractors in London Village - I know a few, but none that would be prepared to come in over a BH weekend to re-point some other contractor's work. Most of the Contractors in my little black book are really only interested in larger works, 100m2 minimum.

You can do this yourself - believe me. Take your time, don't rush it and make sure it's not done during the heat of the day (assuming we get a bit of heat!).

Frankly, I'd insist the contractor comes back and finishes their own work in a professional manner, but it sounds as though you're chasing shadows. :(

Thanks! Talking to you is a welcome change from raking out mortar! Thanks for the tip re. using a roofer's pick; it's proving to be a worthwhile investment.

The contractor, "I've got so many other jobs, that I can't possibly fit you in", is prepared to pay his mate for a few hours to do the job. As you've gathered, we don't have much confidence in his mate. Hopefully, we'll find someone else to lend us a hand and get some money back from the contractor.

I do have to plead guilty on one count - I took Marshall's advice about laying the paving on a bed of mortar rather than dry sand/cement. This makes it all my fault!

One day when the garden is looking lovely, all this will seem worthwhile..........

Best Wishes

Hi again Tony,

It's taken a fair old while, but we've finally got there. We spent about 3 days raking out mortar and removing mortar stains from the slabs and brick edging. There was a long gap due to all the rain we've had "Down South" (it was never as wet as this in Blackpool, where I come from!). The football caused a few delays too.

Anyway, a contractor recommended by a friend has finished the job and the original contractor has paid his costs.

It would have been nice not to have had all the hassle, but it now looks acceptable, even to my wife!

Thanks for all your advice - it really did help us to work out what to do.

Regards

Dominic

Great to hear you got it all resolved, eventually, Dominic - any pictures?

Hi Tony,

I have emailed you a couple of pictures. As you will see, there are some mortar stains. How long should I leave it before cleaning with an acid wash? After all the hassle with the pointing, I don't want to damage it!

Regards

They don't look too bad to me, Dominic. I'd leave it until the end of the summer, as light staining will disappear over time due to the natural chemical reaction with acid rain.

Acid washing is all well and good as a last resort, but it can adversely affect the colours used in concrete pavings, especially the buffs. Have a look at them in, say, September, and then decide if and acid wash is still necessary.

I'll upload your photo's later, if I get the time. :)