Green jointing

[Phillips900]

Hello

I laid an Indian sandstone patio a 2 months ago. It was my first ever effort at laying a patio and I was really happy with the results. Until now! Algae has started to build up in the joints. It was pointed using a fairly dry sand and cement mix 4-1. When I say fairly dry, it would hold its shape when compressed but no water seeped out. The bit I did first was a little wetter but it took me ages to do so that's why I started using a dryer mix. The part done with the wetter mix is aslightly different colour but it's not too noticeable as it's near the back of my garage. This first section doesn't seem to be affected by the algae yet! Is the algae growth due to the dryer mix being slightly more porous than the wetter mix? And is there anything I can do to stop it?
Cheers

[PavingSuperstore]

Is there a run on the patio to prevent the rainwater sitting there in the joints? Also, is this particular area of patio North facing?

[Phillips900]

Yeah the run is 1 in 60 and it's north facing

[DempseyLiverpool]

Dry mix never lasts. Did you use building sand too ?

I'd recommend weather point 365 or similar for diy patio.

[Azpects]

or EASYJoint but then we might be a bit biased on that front

(That said we recommend base mixes of 6:1 or weaker for use with products such as our own, the water has to be able to drain away and can just sit in the joints with stronger mixes)

In regards to Green Jointing, we have two products which would kill it - Algae Remover or Black Spot Remover

http://www.azpects.co.uk/products/easy-algae-remover.aspx

http://www.azpects.co.uk/products/easy-black-spot-remover.aspx