Patio advice for cleaning/treating: Limestone

Delvis · 5 Sep 2021 at 10:45

Hi all,

I've got a limestone patio paid and wondered if anyone else has dealt with the same at all?

Need to clean it up, seal it and point it.

Obviously I want to get rid of any staining or mortar residue, so any advice is appreciated if you've wirk do with limestone

Thanks

Delvis · 8 Sep 2021 at 08:56

j.col said:
You don't say what colour the patio is, as black can fade very quickly.

Don't use anything acidic on limestone, think soapy water is the best afaik.

I wouldn't point using mortar, as over time this will crack/shrink.

We use a product that is just swept in when the slabs are wet (you need loads of water) but its possible to joint a 20m2 patio in less than 1 hour. eg. Easyjoint or Joint-It, (we find the Sika stuff is rubbish) and you can get different colours.

here are a few links for you to read

https://www.pavingexpert.com/stonpv05
https://www.pavingexpert.com/sealant_03
https://www.pavingexpert.com/sealant_trials

Apologies, grey limestone.

I've been tempted by the sweep in stuff, my only worry is filling it where the aqua drain grate is and on a step....

Thank you for the links I'll have a read

I've got lots of smaller lighter coloured circles, small ones, in presuming it's just standing water that's got to them at some point.

Delvis · 9 Sep 2021 at 08:11

j.col said:
We sweep in jointing compound all the time along Aco channel drains, its easy to just brush off any excess on top of the grate with a soft bristle hand brush,
Recess manholes. either tape over the edge gaps, or lift and remove the manhole lid so no stuff falls into the joint.

Often use it on steps as well, just push it in by hand if there is a joint overhanging the step, it wont fall out once it hardens.

Regarding the small light circles, were the slabs laid on a full mortar bed?
It sounds as they may have been laid with dot n dab method (slabs laid on spots of mortar, with gaps underneath the slab), if it was laid this way, the circle spots will be very hard if not impossible to remove.
Slabs should never be laid this way

If they were laid on a full mortar bed, as you say the circles may be just water stains, limestone is porous. Hence why you are looking at a sealer lol

Yeah full mortar bed, did it myself. Shame, bit sure what to do about them, part of me wants to try get rid but then part of me realises they'll probably pick up all sorts anyway over time.

That's good to know about the ACO channel actually so thank you. Is there a better way to get it straight into the gaps between the slabs? I'm scared of it staying there too long and staining

Delvis · 9 Sep 2021 at 18:24

j.col said:
If you use jointing compound, there is no such thing as too much water.
The water actually helps the grit to settle in the joints.
The grit is covered with some sort of oil, so using loads of water helps to remove the oil.

But... it can be messed up ( personal experience) and i ended up with little oil stians because i didn't use enough water.
These did dissappear after a few weeks, but i learned that lesson.
As long as the slabs are kept wet, they won't stain, just make sure you sweep off any excess grit before it dries

Aye watched a few videos about different brands.

Starting to doubt it now as some people say it needs redoing after a couple of years, then at the same time I'm not sure I can be bothered to go hands and knees and mortar it either.

Honestly, main concern is it's limestone and it just not going well.

Delvis · 10 Sep 2021 at 12:55

bainbridge said:
I unwisely used a sand and cement mortar for jointing and the cracking has really annoyed me

It's what's been used for years so I can see why people use it. I've heard of the sweep in stuff going off colour after a few years too, so I can't see pros and cons

Delvis · 11 Sep 2021 at 10:50

j.col said:
We have been using it for over 10 years, and have never been called back over it (unlike mortar)

saying that, i have seen slabs pointed with mortar look good after been down for years.

"A high strength mortar is required for effective jointing, therefore a standard Class II 3:1 sand/cement mortar, or a 1:½:4 lime mortar should be used, but it can be 'beefed up' by the addition of a strengthening additive such as Styrene Butadiene Resin (SBR), which not only improves the bonding properties of the mortar, but also improves water-resistance and hardness."
https://www.pavingexpert.com/jointing02

If using a dye, make sure to gauge it properly
eg. 3 buckets of sand, 1 bucket cement and a container with the recommended amount of dye and SBR (plastic measuring jugs can be good)

How many M2 is the patio?

It's about 34m2 all in, patio and two paths essentially.

I'm probably going to just go down the sweep in route with EasyJoint or something, I just don't like the idea of throwing it all down on the patio though

Delvis · 11 Sep 2021 at 14:56

j.col said:
We tend to use Joint-it more than easyjoint, mainly because the joint-it comes in 2 bags in the tub so its easier to store if 1 bag is unopened.
Travis Perkins sell it for about £30 per tub

Depending on joint widths, it will take 3 to 4 tubs of joint it for 34m2, wider joints may even require 4 or 5 tubs.

How we use either is to empty the bagged contents into the tub, fill tub with water and give it all a good stir.
Wet down the entire area with the hose, and then using a trowel or something, place half the grout out on a large slab and sweep in from there.
Its much easier if you have someone spraying with the hose (mist or spray, never jet) all the time whilst you sweep.
Try ans sweep off as much of the excess grout as you go.
Never let the slabs dry, even ones you have jointed, just keep them damp.
When you are finished the area, go over it all while slabs are damp and try and remove as much excess grout as possible with your brush (soft bristle)

The videos you watched will have shown similar

Any left over compound thats not in a bag can be placed back into an empty tub and the tub filled with water, this will last for about 12 months before going off

Thanks for that, I've seen a couple of videos where they filled the tub, is that just to pre-soak the stuff then? Rather than putting it into the wet slabs and wetting from there?

I did look at joint-it, but the company seems pretty small hat? So was favouring easy joint but I appreciate the preference from your side.