Crumbling Pointing

[applepie]

Help !

I have just finished pointing my patio, I used ready mixed mortar and wickes red cement dye.
Its been down for a week or so and is crumbling, when i dig a bit out it snaps just like a biscuit.
Other pointing i have done with this ready mixed mortar has been fine and sets really hard.

Should i be using something else for pointing a patio ? or is it the cement dye causing the problem ?

TIA for your help

[brithebuilder]

Hi,
If you check the dye manufacturers instructions you'll almost certainly find that when added to mortar the mix should be made stronger. I've used dye many times and it's very important to stick to the quantities specified by the manufacturer.
The type of sand used is also important, for pointing slabs sharp sand is preferable. The alternative is to buy a proprietry ready mixed mortar designed specifically for paving.