Grout's dried out really patchy - HELP!!!

[jolly bodger]

Hi all,


Just finished tiling a bathroom - full height + floor in 600 x 300 "Thassos" (very, very light grey-ish) porcelain.


Proper job, mitred window recesses to create a uniform 2mm grout line on the edges, no collars needed for any pipework as it just pops straight out of the tiles etc etc etc. Took an extra day and a half to complete to this standard and it really looked the business...


and then I grouted...


Used Mapei 111 (light grey) but it's dried out really, really patchy. Grout on Mosaic feature just fades into the background, yet elsewhere stands out and defines tiles as the client wanted! Rectified edges on the tiles but no shadowing, half mm off level occasionally here and there but no more than that.


Have always grouted walls either white or jasmine (beige) and never had a problem. Tile shop reckons its salts rising to the surface of the grout and discolouring it and suggested washing and washing and striking it off.


Just spend 8 hours doing so to little effect - client in tears, payment on hold, toilet and bath fitted out of necessity but other furniture still sitting awaiting a solution...


nightmare...would sealing the porcelain give the grout a uniform apperance?


As ever, any help appreciated!!!


P.S. all walls are brick + plaster skim finish

 

[DHTiling]

What adhesive type did you use ..?

How long did you leave the grout to set before washing down.?

 

[AliGage]

As above. + Is it new skim on the walls?

 

[nybor62]

as all the above, seems to be quite a common thing probs with grout going patchy, it must be user error surly ive never had a prob
with mapei grout or any other grout going patchy

 

[Gazzer]

How long has the grout had to dry ?

 

[cam_low]

Did you prime the walls? What sticky did you use?

 

[jolly bodger]

Hi guys,

Many thanks for the replies

Used Ultra Pro Rapid RS Porcelain in white for the adhesive, and did an initial wash down about 25mins or so after application. Grout had dried to a film on the tile surface at that point

New skim on two walls, been left to dry for a week or so. Previous tiling had been full height bath area and rest half height and all tiles stuck on in 70's with contact adhesive ("tiler" must've been high as a kite!)

Worst area is behind bath, that wall was only stripped, 95% of contact addy chipped off and then tiled over, but patchy everywhere.

Grout's been dry 5 days now, walls weren't primed with anything.

Mapai Tech support reckon it's salts, and if I sand the grout lines it does reveal the colour, but I need to go down 1 or 2mm so seems pointless. Tile shop reckons grout might've separated out in transit and I should've shaken the bag (Mapai bag doesn't say contents may settle) but I mixed 75-80% of the bag first time round so...

Any ideas? Tile shop have offered loan of a grout remover tool with a vibrating point on it to dig the old grout out.

As ever, any help appreciated

 

[jolly bodger]

Used Ultra Pro Rapid RS Porcelain in white for the adhesive, and did an initial wash down about 25mins or so after application. Grout had dried to a film on the tile surface at that point

New skim on two walls, been left to dry for a week or so. Previous tiling had been full height bath area and rest half height and all tiles stuck on in 70's with contact adhesive ("tiler" must've been high as a kite!)

Worst area is behind bath, that wall was only stripped, 95% of contact addy chipped off and then tiled over, but patchy everywhere.

Grout's been dry 5 days now, walls weren't primed with anything.

Mapai Tech support reckon it's salts, and if I sand the grout lines it does reveal the colour, but I need to go down 1 or 2mm so seems pointless. Tile shop reckons grout might've separated out in transit and I should've shaken the bag (Mapai bag doesn't say contents may settle) but I mixed 75-80% of the bag first time round so...

Any ideas? Tile shop have offered loan of a grout remover tool with a vibrating point on it to dig the old grout out.

As ever, any help appreciated

 

[jolly bodger]

Used Ultra Pro Rapid RS Porcelain in white for the adhesive, and did an initial wash down about 25mins or so after application. Grout had dried to a film on the tile surface at that point

New skim on two walls, been left to dry for a week or so. Previous tiling had been full height bath area and rest half height and all tiles stuck on in 70's with contact adhesive ("tiler" must've been high as a kite!)

Worst area is behind bath, that wall was only stripped, 95% of contact addy chipped off and then tiled over, but patchy everywhere.

Grout's been dry 5 days now, walls weren't primed with anything.

Mapai Tech support reckon it's salts, and if I sand the grout lines it does reveal the colour, but I need to go down 1 or 2mm so seems pointless. Tile shop reckons grout might've separated out in transit and I should've shaken the bag (Mapai bag doesn't say contents may settle) but I mixed 75-80% of the bag first time round so...

Any ideas? Tile shop have offered loan of a grout remover tool with a vibrating point on it to dig the old grout out.

As ever, any help appreciated

 

[AliGage]

Did the porcelain require sealing beforehand? Can't really tell from the pictures, but looks like a lot of residue still remins. What tiles are they?

 

[Andy Allen]

you could use a grout colourant to fix the problem...

just out of interest how heavy are those tiles per m2...

 

[johnryan]

but I mixed 75-80% of the bag first time round so...

you may find that the problem is there. from my understanding mapei grouts have to be mixed as per instructions, with correct amounts of water, ie 1ltr for big bag and 1/2 liter for small bags, also need to be mixed with small paddle too, then let to settle then mixed with small paddle again before use. very good grout but need to be prepped properly or you can have problems with it. just to add, i only know this as they showed us the right procedures for mixing their grouts on a training day at mapei.
​

 

[macten]

Just to add to the advice above;

Initial wash down needs to be with a sponge that is ever so slightly damp. If you are getting water standing in the joints (even a drop) then it's too wet and the polymers will rise to the surface and you end up with what your photos show.

Obviously subsequent wash downs can be a little wetter as the grout will be much firmer by then.

 

[jolly bodger]

Tiles were Italian porcelain, from Casalgrande Padana, Granitogres range, the colour is Thassos and the tile shop says they don't need sealing. Look expensive!

They're 300x600x9mm and weigh just under 21kg per m2.

I'm guessing it must be user error then, didn't shake the bag up, should've mixed the pack in one go and prehaps too much water for washing down...still doesn't seem right though, patchiness is terrible and I find it hard to believe it's ALL down to me - being using Mapai grouts for years and never had this!

Anyway, happy ending is I'm removing the grout and'll replace it with white (mocked up 3 mosaic panels with 100 white, 111 light grey and 112 cement grey and client wants white.) Tile shop's buzzy tool is getting the old grout out a treat and no damage to tile edges either - a lucky escape methinks!

Thanks for all the replies ladies and gents

 

[Blake Tiler]

Go to National Tiles for a Mapei Grout pen. Get your grout colour in this case get a 111pen. You can thank me later.