New Tiled Floor Problem, Advice Please?

[Sloter]

Hopefully that worked, what do you think?

 

[Andy Allen]

Grout looks very patchy .
Any pipe work under the floor?

 

[Sloter]

I really don't know. I'll need to ask the builders but they seem very cagey about it all. Do you think it looks like water underneath the tiles?

 

[radim]

Try sandpaper and see if helps

 

[hmtiling]

looks like a spillage

 

[Sloter]

looks like a spillage

Any idea of what? It's not dried out in 7 weeks.

 

[hmtiling]

Any idea of what? It's not dried out in 7 weeks.

something that would stain the grout. as above, try sanding it back and you;ll know if it's just surface marks

 

[Sloter]

something that would stain the grout. as above, try sanding it back and you;ll know if it's just surface marks

Ok thanks, is it worth trying a grout rake?

 

[hmtiling]

Ok thanks, is it worth trying a grout rake?

No probs. yeah, that'll work.

 

[LM]

There are a multiple of things that can make grout patchy like the majority of the grout in your pics are,
Poor quality grout
Joints that aren't properly cleaned out before grouting which leads to different depths hence different shades Too much water either by unevenly mixed batches
Too much water left on different parts of the floor after poor washing off
Efflorescence can even form if the grouting was done in an area where a cold channel of air is blowing through, say at doorways etc because the grout stays wet too long in those areas which then dries slower in those specific areas, the slower it dries the lighter it will be
As for the extremely dark patch in the pic it looks like something has been spilt on the joint and stained it, if there was a leaking pipe its more likely that the 'wet' looking patch would be more over the floor in general and it would certainly be growing in size