Builders sand / sharp sand

[transatlantic]

I picked up some sharp sand the other day to mix with some cement to make up a mortar to fix the pointing around some patio paving slabs. I noticed straight away that the sand seemed very red, and would actually stain your finders orange if you touched it (it was very damp), but thought I would give it a try anyway as I could always pull it back up if the colour match was terrible, and didn't match the existing grey pointing.

Well, giving it 5 days to dry completely, the colour match is petty bad and it stands out like a sore thumb, basically looks like sand (although is rock hard), so I probably am going to pull it back up, and do it again (it's only a very small section , so no bother)

Having gone back to the builders merchent, both their sharp sand and builders sand are the same very red colour, and ooze the orange liquid (if you squeeze it) that stains your skin. A little bit of research leads me to find it's just another source of sand that has a higher level of iron-oxide. Sometimes they'll source the normal beach type colour sand, and other times they'll get the reddy iron-oxide, depending on what is avaliable at the time.

So I'll give it a few weeks and try again to see if their stock has changed.

So, whats up with that? surely no one is going to want to use mortar that ends up being orange/red?

 

[MikeG.]

Sharp sand isn't what you would use for pointing ordinarily. You need soft washed or plasterer's sand.

Sand colour is independent of whether or not it is sharp or washed. It is solely a function of which pit it was dug from. In fact, it's more subtle than that, because even the same pit can have differing strata or pockets. There are lots of uses of sand other than mortar, and in some areas, reddy mortar is traditional anyway.

 

[novocaine]

you shouldn't really use sharp sand for pointing, it's to course. thats another matter though.

round here it's mainly Mersey sharp or screened builders sand and it's all high oxide content, so most new houses are reddish mortar.


edit : crossed with Mike.

 

[transatlantic]

The only reason I used sharp sand is because the existing pointing mortar is quite "bitty/course", not smooth, so I guessed they orginally used sharp sand, but not sure. I was trying to match what was already there, which I guess is more tricky than I thought.

 

[novocaine]

It does fade eventually, but you're looking at years rather than weeks. you can add pigments if you want a specific colour but you are better doing the whole lot to match rather than try to match.

 

[transatlantic]

It does fade eventually, but you're looking at years rather than weeks. you can add pigments if you want a specific colour but you are better doing the whole lot to match rather than try to match.

95% of it is fine. It's just in one corner where the pointing has failed.

 

[sammy.se]

The only reason I used sharp sand is because the existing pointing mortar is quite "bitty/course", not smooth, so I guessed they orginally used sharp sand, but not sure. I was trying to match what was already there, which I guess is more tricky than I thought.

you're sure it's not lime pointing? That can be gritty....

anyway, I picked up a bag of plasterers sand from Wickes recently for £3. Did the job (for a small quantity). Pointing patio slabs

 

[Oddbod70]

The only reason I used sharp sand is because the existing pointing mortar is quite "bitty/course", not smooth, so I guessed they orginally used sharp sand, but not sure. I was trying to match what was already there, which I guess is more tricky than I thought.

You can use sharp sand if you want. People normally use soft 'cos it's a bit easier, but it's no big deal either way.

It can be a mugs came trying to match the colour. The only hope is that the sand came from somewhere fairly local. Just have a look round the local builders merchants and keep your fingers crossed you find something fairly close.

I've given up pointing patios the traditional way. I've had my fill of laying random reclaimed Yorkshire flags! Now I go for spending time on preparing a really solid base, buying consistently thicknessed paving and finishing with a resin based grout. Expensive, but quicker, kinder on the back and lasts longer. No good for patching up a few gaps though.

 

[transatlantic]

you're sure it's not lime pointing? That can be gritty....

anyway, I picked up a bag of plasterers sand from Wickes recently for £3. Did the job (for a small quantity). Pointing patio slabs

No idea to be honest. I'll try some plasterers sand as from memory, that was one of the products that looked the right colour. I only dismissed it because of the name, and the fact that I wanted something more coarse.

 

[novocaine]

not likely to be lime for a patio, more likely a high cement mix that was brushed in dry then wetted out.
it will have gone grey over the years. as said, you aren't likely to find an exact match as it's not be weathered. if you are happy to have "close enough" then go with builders or plasterers sand. it will eventually match again and is more likely to get there quicker.

I have to repoint the entire house in the next year, glad it's painted for once, don't have to worry about colour match to the new build portion of the house.

 

[sammy.se]

Yes - agreed, not likely to be lime for patio pointing! Brain-fart moment. I hear 'gritty pointing' and my mind rushes to Lime