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Posted: Sat Aug 25, 2012 9:01 am
by Surrey_Rob
Hi everyone,
I'm about to attempt my first patio and I have a bit of a dilemma !
Screeded dry mix or full mortar bed ?. ???
The slabs are going to be black limestone with sawn edges and all machine cut to same thickness, so I'm thinking it would be a lot easier for the novice to lay on the dry mix perfectly flat screeded option, right?.
Any advice would be greatly appreciated chaps...
Oh and seeing as I've not got the slabs yet, any recommendations on best place to get them from would also be a great help 
Thanks in advance 
Posted: Sat Aug 25, 2012 9:05 am
by Surrey_Rob
Forgot to say that I will be doing an area of approx 50 square metres,
also I never mentioned that I'm in Egham in Surrey.....
Posted: Sat Aug 25, 2012 9:09 am
by Carberry
Screed it with a moist mix. Don't want to mess about with individual bedding and black limestone as a novice, it can get real messy real quick.
Try Londonstone for slabs
Clean the slabs as you go. Can't use acid on the limestone so make sure you wipe up any cement before it stains.
Posted: Sat Aug 25, 2012 10:40 am
by London Stone Paving
Hi Rob
Cheers for the reccomendation Stewart. I'm going to have to disagree with you though about the installlation. It might be more complicated to lay a flat screed out. I would opt for a mortar bed.
Our black limestone has a really flat surface and a machine cut edge, its also calibrated to 25mm. I would say it is one of the least challenging stones to lay. We are based about 10 minutes from Egham, I am here all day today and could talk you through the installation in a bit more detail if you are passing.
Also you must heed Stewarts advice about cleaning as you go, its absolutely essential because dry mortar stains are impossible to shift from black limestone.
Steve
Posted: Sat Aug 25, 2012 10:43 am
by Surrey_Rob
Ok thanks for the tips .... Just a few things though, what's a moist mix consist of ? also should I coat underneath the slabs with a bonding agent that I've seen on here somewhere ?... Finally would I be able to use a resin slurry type mortar on these slabs ? as I really don't fancy pointing 50+ metres of patio...
Posted: Sat Aug 25, 2012 10:51 am
by London Stone Paving
I would opt for 5 parts sharp sand and 1 part cement. To a certain extent the wetter the mix is the easier the stone will knock down, however if you go too wet you can risk making a real mess because all the mortar will come through the mortar gaps and smear over your slabs. The key to doing it right is getting the correct amount of mortar in your bed. This will be made much easier if your subase is consistent in level. Also by using calibrated stone you should be able to settle into a routine.
For the pointing go for easipoint or marshalls weather point. There are long term question marks over these products but they are perfect for DIyers like yourself (no disrespect meant)
Steve
Posted: Sat Aug 25, 2012 1:21 pm
by Surrey_Rob
Does anyone have any pics of a black limestone patio that has been in use for some period of time ? or know where I can find some pics of one? as I'm a little concerned that with some wear and tear, chair scrapes etc, it might look knackered before too long and that maybe I should consider a lighter stone colour ???
Posted: Sat Aug 25, 2012 1:36 pm
by mickavalon
If you don't seal Black Limestone, it very quickly fades to a mid Grey/charcoal colour, but obviously darkens when wet. If your wanting a Black finish at all times, then you either need to seal it or use something else, maybe Basalt or Black Granite(much more expensive).
As for layng on a screeded bed, We sometimes do it, but we screed a 40mm cement/sharp sand bed, semi dry, to falls and levels and then actually lay the Paving on a thin full Bed of mortar 6:1, mixed with Building sand, with SBR, but only with thin calibrated Paving, so the effect is more like internal Flooring. It works fine, but takes a bit of practice, and you don't want your mix either to wet or Dry, Brickies mix is the best, so a bit of Plastisisor in it. we find it helps get the jointing spot on and it's also cheaper if your using white cement. Forgo to say it really only works with linear patterns, not random, unless you allow the screed bed to set first, otherwise you end up walking all over your screed bed.
Posted: Sat Aug 25, 2012 1:42 pm
by Carberry
Surrey_Rob wrote:Does anyone have any pics of a black limestone patio that has been in use for some period of time ? or know where I can find some pics of one? as I'm a little concerned that with some wear and tear, chair scrapes etc, it might look knackered before too long and that maybe I should consider a lighter stone colour ???
See this page about black limestone
Found Londonstones stuff cut well enough to lay on a screed and reason I suggested it is because of the problem of possibly making a huge mess when using individual bedding.
Posted: Sat Aug 25, 2012 3:43 pm
by Surrey_Rob
Carberry thankyou for your post, very helpful page about black limestone
Steve @ london stone, I was just in your place at stanwell the other day, I picked up a couple of samples of black limestone, I obviously didn't look at the company name when I was there (wife always says I'm not very observant), but just seen the pics of your display area on here and thought "that looks familiar" I will pop in some time next week and have a chat if ok?
Posted: Sat Aug 25, 2012 4:36 pm
by London Stone Paving
Not a problem Rob, can give you plenty of advice on installation etc
Steve