Grout patchy colour - Tile Advice

[Anna Rack]

Thanks to the help of this forum, have successfully completed tiling my small bathroom with 50mm marble mosaics. :hurray:

I used Mapei jasmine ultracolour plus grout and overall am pleased with the finish etc but in quite a few places it's patchy in colour with a few dark areas. Not that noticeable but annoying.

I mixed it thoroughly and after applying, left it for about half an hour until it was quite firm before sponging off so as far as I know did everything as per the instructions. Anyone encountered this before?

Not a great picture, but the areas on the left are more pronounced.

 

[Time's Ran Out]

Was the tiling onto plywood?

 

[Anna Rack]

No. tiled onto marmox type board and used Ultra proflex adhesive which had been dry for 24hrs+.

 

[merit]

when using ultra colour plus mapei grouts , all instructions must be followed,
correct amount of water per bag,mechanically mixed, left to slump, mixed again,do not use excessive water when wiping off ect , i couldnt get away with it at first but use it on all porcelain and stone work now , there is a sticky on the procedures on the forum somewhere

 

[Time's Ran Out]

Full picture looks good!
It's usually in the mixing as Mapei ultracolour plus (especially Jasmin) tends to have specks of orange/rust colour in and they can bleed into the grout after it sets. You could scrape it down and over grout with a new mix in the areas of patchy.
Annoying when it happens but still the best grout around IMHO.

 

[DHTiling]

Was any adhesive proud in the joints..?

 

[Anna Rack]

No, I made sure all adhesive was below the grout level beforehand. I did think it might be where the adhesive was close to the top of the tile and the grout was thinner, but the discolouration is also in areas where no adhesive had been pushed up.

 

[DHTiling]

Did you hand mix the grout or use a paddle mixer..?

 

[Anna Rack]

Hand mixed as per instructions. As it was my first use of Mapei grout I didn't want to mix too much in case it set too quick, so ended up doing the floor with 2 seperate mixes. The first mix was possibly a bit too watery so next time made it a bit thicker. Didn't make any difference to the finish though.
Don't think I rewetted too much when smoothing but it was pretty much set hard anyway.

 

[kilty55]

looks like the colour has possibly not been mixed sometimes the orange colours can bleed out during mixing but its fixable

 

[DHTiling]

It does say to mechanical mix on the instructions .. this makes it easier as TJ also mentioned about pigments..