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Posted: Mon Jul 16, 2007 11:58 am
by PHDA
Hi,
I've just laid an Indian Sandstone patio on a full bed of 10:1 mix, with a plan supplied by Tony. I've been reading up on the best way to point the slabs and am interested in Rompox Easy, some sites say it is supplied in 25Kg tubs and specify coverage at 8-12m, but it appears Rompox is now suppied in 15kg tubs does anyone know a fairly accurate coverage rate for a 15Kg tub. I don't want to over order or even worse under order.
A second point is that I've read Rompox easy is permeable and allows all the water to seep through to the bedding layer. Is this correct and will it do any harm to have water seeping through under the slabs.
cheers for any advice
Posted: Mon Jul 16, 2007 4:24 pm
by lutonlagerlout
not a lot of water seeps through,only if you get a particularly riven flag that holds a bit of water, will it seep through.
no way of guestimating it exactly but i reckon 1 15 kg tub does about 7 m,but this is affected by joint width and depth
put it this way if your patio was 30 m2 then i would order 5 tubs to be on the safe side
btw if i remember rightly bannister hall charge the same haulage per tub,whether you have 1 or 50
regards LLL 
Posted: Mon Jul 16, 2007 4:50 pm
by PHDA
The problem I have is that there is not a great slope on the paving. This was done on purpose because it adjoins a decking area and I had to follow the slope of the decking. My fear is that in the winter water will get under the slabs and freeze.
Why is Romex permeable anyway, are there any benefits to having a permeable jointing compand.
Posted: Mon Jul 16, 2007 9:01 pm
by lutonlagerlout
if you havent got the correct fall i.e. 1:60 then you are bolloxed to coin a phrase
i tried to do something similar 3years ago and after 1 winter the whole patio was a green slimy mess
decking is obviously permeable due to the gaps but flags??
best let the gaffer advise you on this one mate
cheers LLL
Posted: Thu Jul 19, 2007 12:00 pm
by Tony McC
Permeable pavements are "the next big thing" in pavement construction, so it makes sense to have a permeable jointing material.
If you have an impermeable laying course, then once the joints are saturated they will simply overflow and the excess water will have to drain across the surface of the paving, so you *still* need a crossfall, even if you have used a permeable jointing material.
Posted: Sat Jul 21, 2007 10:25 pm
by PHDA
Reading the instructions on the Rompox tin it says " Only to be used with a permeable foundation, if water is allowed to stand in the joint the rompox compound will eventaully breakdown". To me it seems Romex is only suitable if you have a permeable bedding layer or there may be problems later on. No matter what fall the slabs have water is bound to seep into the joints and sit there if the bedding layer is impermeable.
I've got 2 tins of the stuff now so am going to use it anyhow, i'll let you know if there are any problems after the winter.
Posted: Sun Jul 22, 2007 4:02 am
by Suggers
Lots of our current flooding/surface water problems are due to us not using permeable solutions.
Posted: Sun Jul 22, 2007 12:16 pm
by PHDA
This may seem like quite an off the wall solution but I am going to try drilling holes through the bedding layer at the joints. All my joints are at least 10mm so it won't be a problem getting a long thin drill bit in. I am then going to brush in a thin layer of sharp sand into the joints before filling with Romex, hopefully the water will then drain through the Romex and the bedding layer.
Posted: Sun Jul 22, 2007 12:25 pm
by Tony McC
That'll work for a couple of weeks ... after that, the sand-filled 10mm dia holes will "silt-up" and you're back to square one, I'm afraid.