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Grout has dried rough with little visible grains

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Hi all . Used some Mapei mould resistant grout when re tiling kitchen with 10x20 metro tiles . Grout has dried rough with little grains visible . What causes this and how to avoid and ensure a smooth grout line .
Was only a small area so had to mix a small batch so maybe the ratios were out ? If the case . What ratio do I use for a small areas worth ? How long do you wait before removing excess and wiping off etc ?Many thanks
 
You can use weighting scales to get ration correct. Just need to read data sheet online or packet. Do maths.
4 grams of powder to 1grams of water is 4 to 1.


Clean tiles as you go with sponge. Just get worst off.
When grout is setting which you test with finger. It firms up. Run something along the group lines to smooth off.
Then damp sponge off the tiles.
Dry microfibre off .

If grout has set enough you won't damage when cleaning tiles
 
Ah right so it’s weight for weight not by volume ? What’s a good grout smoothing tool ?
Ty
 
Rub it down with the corner of a sanding block, scraper or with a grout rake then go over it again

Ensure the mixing bucket and mixer is immaculate. apply with a clean rubber grout float. How long to wait depends on internal temp, humidity and how wet the wall is. In the height of summer heat and a very dry wall you might be wiping it off as fast as you're putting it on

Generally when it's gone slightly stiffer(rub at some that's on a tile) you remove most, then come back when it's firm for a determined go-over, but don't try to get the wall immaculate - leave a haze and clean it properly when the grout has set/dry. Use a grout sponge, more coarse/holey and stiffer than eg fine sponges like those things you clean pans with
 
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Thanks . What’s the best way to apply to get smooth defined grout lines ? How long fonyounwait to remove excess and then wipe with the sponge ?
 
Mapei Anti-Mould Flexible White Coloured Tile Grout
This stuff usually dry smooth ?
 
Thanks . What’s the best way to apply to get smooth defined grout lines ? How long fonyounwait to remove excess and then wipe with the sponge ?
I edited the post above but generally if you've got a contrasting grout the way to get defined lines is to make sure there aren't any bumps in the grout that spill out sideways on the rounded edge of the tiles. Wipe diagonally for the most part so you're going across the grout line at an angle, but if you notice any humpy spots either strike them out with a scraper that has a slightly rounded corner, carefully use a fingernail, or focus your sponge rubbing a bit more in line with the grout line but not so hard that you dig the adjacent lower spots out

As noted you can't really give a minutes and seconds wait time as it depends on a lot of factors but it's a bit like trying to clean melted chocolate off a fabric; if you rub it with a sponge the surface starts coming off but you just keep gently polishing at it to diminish it. The texture of the grout is a bit like soft chocolate when you're starting to do the sponging, and you don't want a wringing wet sponge but do clean it frequently

Being diligent with your rubber grout float in making sure there aren't any massive lumps will help, and metro tiles are a bit more of a nuisance because of the edge profile/chamfer but a careful run over with the float and a rounded corner will help ensure there isn't a huge mound of it somewhere while not digging out between the lines much

If you've fitted your spacers so the plus shape is touching four tiles (ie you're thinking of grouting it in, maybe take some time remove it ; an oscillating multi tool works great for this

Re the Mapei grouts o don't usually have a problem with them being grainy, and though one of my bathrooms at home that was done by someone else does occasionally have a bit of a lump. I don't know what happened with it cos the rest of his tiling is spot on, maybe not quite clean bucket, but it's slight and I've got bigger things on the list! One day I'll rake it out and do it again.
 
I've also had good results from Butech Colorstuk Rapid (Porcelanosa) - Manhattan

Delivery from porcelanosa is 60 cos they pallet everything, expecting you to buy tiles too.. eBay has a few listings for this grout at about 15 a bag delivered
 

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