I will shortly be laying 30m2 of Indian Sandstone Paving Slabs and after reading the PavingExpert website was intending to use the Screed Bedding method to make the job quicker and easier, but have seen several suggestions that it for a DIYer it might not be such a good idea so am not unsure how to proceed.
The slabs are 22mm calibrated Indian Sandstone (900x600, 600x600, 600x290, 290x290)
The base it well prepared and compacted with a constant gradient, the base was screeded level so have a lovely smooth surface to work from with no camber or changes in slope, etc
I also have two 35mm diameter steel tubes available to use as screed rails and a 3m long screed board.
I will probably be hiring a cement mixer.
Will I still be better off keeping to the individual bedding method rather than trying the screed method.
My main concern with the individual bedding method is getting the amount of bedding material correct, as when I tried it 10 years ago with cast concrete slabs I spent an age getting the heights correct either lifting them to add extra bedding material or having too much that I could compress them down enough without risking breaking the slabs.
Could I perhaps use some screed rails to lightly screed (uncompacted) an area large enough for one or two slabs to get a consistant thickness of bedding material.
I assume an SBR mix to the base of each slab would be a good idea if I am careful.
I intend to use a 5:1 or 6:1 sharp sand/cement mix, although unsure if semi-dry or moist would be best.
Patio - screed bedding or individual method - S
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Tony McC
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You *could* screed, but I would keep the bedding to an 8:1 or even a 10:1 mix, and minimal added moisture. What we want is to extend the working life of the bedding for as long as possible: have it too strong and/or too moist in these summer temps and it will go off in under an hour.
I would suggest not screeding out more than you know you can cover in, say, an hour. Screed a bit, get it covered, then screed a bit more, sliding your rails forward as necessary to prevent them being buried.
You'll have to work from the screeded bed, so plan how you will reach each flagstone and place it. I would suggest that you will need to titivate the bed as you progress, as the prefectly screeded surface will inevitably become disturbed. If you aim to keep that disturbance to a minimum, you should be able to 'trowel out' any uneveness using a float trowel, relying on the undisturbed screeded bed as your guide.
Definitely use a bond bridge, but make sure you keep your work perfectly clean. Wash down thoroughly and that added water will help boost the w/c ratio of the bedding as it cures overnight
Take your time and it will work out fine :~)
I would suggest not screeding out more than you know you can cover in, say, an hour. Screed a bit, get it covered, then screed a bit more, sliding your rails forward as necessary to prevent them being buried.
You'll have to work from the screeded bed, so plan how you will reach each flagstone and place it. I would suggest that you will need to titivate the bed as you progress, as the prefectly screeded surface will inevitably become disturbed. If you aim to keep that disturbance to a minimum, you should be able to 'trowel out' any uneveness using a float trowel, relying on the undisturbed screeded bed as your guide.
Definitely use a bond bridge, but make sure you keep your work perfectly clean. Wash down thoroughly and that added water will help boost the w/c ratio of the bedding as it cures overnight
Take your time and it will work out fine :~)
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