November jointing - Advice on jointing compound for sandston

[littlewig]

Hi All

I have left finishing off my patio rather late and it is now late November. I need advice on what to use for jointing.

I have put my standstone slabs on a full mortar bed and have about 36m2 of paved area.I have tried to use mortar in a discrete area, but it seems to be sucked into the slab and will likely stain. I am not sure if there is anyway of stopping this capillary action?

In alternative, can anyone recommend some reasonably priced products. Weatherpoint 365 is attractive but expensive plus I am after either a dark grey or black joint.

Regards

Marcus

[London Stone Paving]

If you opted for a semi dry pointing mix then you will not have the same issue with staining.

It might be worth re-visiting the wetherpoint option. It may seem pricy but if you factor in the quick installation time it's in fact good value for money. Is there not a darker colour availble

[r44flyer]

I recently used Instarmac's Flowpoint to joint our sandstone patio. No staining and it looks great, and quite cheap at £20 a bag inc. Used 4 bags to cover similar area. Comes in natural grey and charcoal.

Best used with a pressure washer to remove surface excess I found.

There's video on youtube to give you an idea of how to use it, just don't hang about as it sets fast.

[cookiewales]

I just done some 2 part expoxy pointing 25 kg sand 25 mil of sika liquid couloir worked well would say it was on staff blues will post up some pic ps I know you can get basalt sand but they had none

[Tony McC]

The semi-dry mentioned by Steve is the cheapest option but you need the surface to be dry, and that's not always possible in November when the ground seems to be permanently damp if not sopping wet.

The secret (or one of them) to avoiding picture-framing with porous sandstone when using a wet mortar is to saturate the paving with clean water a few hours before carrying out the trowelwork. This has the effect of sating the thirst of all those capillaries and so you get much less transfer of stain-making cementitious material.

I must try to put together a page about this.....another one for my list!

[mike builder/landscaper]

We use this soaking the paving method as standard procedure. The night before we point the paving is soaked and as soon as we are able to wet the paving after pointing we will sprinkle water on it. This stops the mortar drying out to rapidly and allows it to cure slowly.

[littlewig]

Thanks for the responses. I should add that I was alive to the risk of staining and did ensure that the area was soaked early on the day I was testing (after reading about the same on this forum). It still seems to have stained despite this. I used a moist mix, but not dripping wet. I have also been struggling to find a sufficiently dry day recently.

I have had a chap at NCC recommending GftK vdw 800, but it is very expensive epoxy that will be around £300 including VAT and delivery.

I was concerned about Flowpoint as to whether it could be used on a full mortar bed - any experience? Like the sound of the price tag if it will produce good results for my low use area as a patio.

[London Stone Paving]

The semi-dry mentioned by Steve is the cheapest option but you need the surface to be dry, and that's not always possible in November when the ground seems to be permanently damp if not sopping wet.

The secret (or one of them) to avoiding picture-framing with porous sandstone when using a wet mortar is to saturate the paving with clean water a few hours before carrying out the trowelwork. This has the effect of sating the thirst of all those capillaries and so you get much less transfer of stain-making cementitious material.

I must try to put together a page about this.....another one for my list!

Top tip from the gaffer

[littlewig]

I also should add I have a patio edged with new wood sleepers and I will have to be very careful that the use of any slurry product does not effect them by getting in grain (and natural wood cracks).

[Tony McC]

You wouldn't have a problem with Flowpoint for jointing paving laid on a full mortar bed and it shouldn't adversely affect the timber sleepers either.

Be aware that the timber will shrink and swell with moisture so the joint bewteen the sleepers and the rigid paving is best filled with sand.

Having timber sleepers as edges is less than ideal but not the end of the world. What I can never understand is why some eejits (and it does tend to be landscapers) insist on using timber as risers for steps and then mortar on a natural stone or concrete flag as the tread! Madness!!

[littlewig]

Thanks for your suggestions Tony. I will try to find some Flowpoint for area.

With regards to the edging, it had occurred to me and I had not decided how to address the problem. You have suggested sand, but won't that just wash away. I have made a raised area with timber sleepers to overcome a slope in my garden. The water will have to pass over some of the timber for the fall and will simply take the sand with it I would imagine. It maybe I need to find some sort of flexible jointing material, although a bit overkill for a garden patio.

[Tony McC]

If scouring of the sand does become a problem, there are various Jointing Stabilisers which would control the loss.