Cement mix for shed roof...not as mad as it sounds

23 Dec 2013
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United Kingdom
ve got a concrete slab shed roof with a block work wall around the top.

When it rains, it fills with water.

There is a drainage point but the rise and fall points AWAY from it!

I want to lay a mix of concrete to create a valley and channel the water towards the drain.

What mix should I use?


Im thinking of adding CEMENTONE integral water proofer?

Then painting ACrypol on top (when dry)

Any pointers advice on the mix ratio?
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did you say there is a concrete roof with blocks round it?? or you mean block walls with concrete roof on top ??

Id be thinking about the weight you want to put up there?
If there is block up there round the edge why not take them off?
or drill a load of holes all round the block work??

you could try a sand/cement mix say 5/1 sharp sand cement but use a sbr slurry coat to key the new gear or it will shell off in the frost/sun.....

then use and tar bitchermin based waterproofer over your cement topping

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