Paving Grout

[custard]

There's a paved area outside my workshop which was becoming slippery with lichen. I power washed it and saw that some of the grout between the paving stones needs repairing.

The problem is that to my untutored eye the grout looks whiter than a normal sand/cement mix?

The same builders laid the paving as built the workshop, and in turn they were aiming to be consistent with an Edwardian property on the same plot. Maybe this influenced them? This is the workshop brickwork.

Does anyone have any advice on how I can mix up a paving stone grout that will give a reasonable match?

Thanks!

 

[Bm101]

You can buy pigments for cement Custard although mixing sand/cement types and ratios will also make a difference. If you're doing it yourself, it's quite important to be fairly precise with measures if you can't mix enough for repairs in one batch to keep colour consistency. Obviously it will also dry a few shades lighter than its wet colour. If you want an exact match might be worth doing a test mix or two.
If you try to match by just adding more cement you could have problems with cracking and shrinking.
Do you know if the existing isa traditional mix? Lime maybe? Local distinctive sand?

 

[Harbo]

White cement and white sand.

Rod

 

[sunnybob]

I have similar coloured tiles and bought limestone grouting.
looks like that to me (but I am a long way away).

 

[MikeG.]

White cement and white sand.

Rod

Will give the right colour, for sure. However, it is more prone to moss growth than grey cement.

 

[Rorschach]

Bleach does a good job at removing moss and lichen so you don't need to resort to power washing as often.

 

[powertools]

With the help of a builder friend I layed a path with paving slabs and he ordered pointing sand that was different to both sharp and building sand.
I also had a patio laid by a different builder and he used the stuff that you just sweep into the joints my advice is not to be tempted to use that as in my opinion it is so bad that l spent 2 days scraping it out of the joints so my friend could then repoint with the same sand cement mix he used on the path

 

[Woody2Shoes]

I think that the mortar used for the bricks is just quite a strong mix of soft sand and cement. Often the source of the sand can cause quite large variations, all other things being equal, in colour.

I think that the grout between the paving stones is considerably weaker (as one might expect) and the whiter areas are efflorescence of salts from the stone and/or mortar mix.

This site is very helpful on all things paving related: http://pavingexpert.com/

If it were me, I'd probably just use soft sand and masonry cement (which is ordinary portland cement with additives to improve its workability e.g. https://tarmac-bluecircle.co.uk/product ... ete-trade/ ) in a ratio of say 5 sand to one cement (you want it weaker than the slabs/stones). I'd expect the grout to weather down quite quickly - starting to look like what you've got already.

Cheers, W2S

You could use "snowcrete" https://tarmac-bluecircle.co.uk/product ... ete-trade/ but I really wouldn't bother!

PS an obvious way to get a better idea of the "original" colour of the paving grout would be to chisel out a small piece and snap it in half (I think you might be surprised how sandy it looks!).