Mortar type

[Letsgetitdone]

Hi just getting ready to repoint my house. I'm not sure if they've used lime mortar or sand and cement. I've attached pics showing white flecks in the mortar which don't really fizz when sprayed with white vinegar. Anyone got any idea?

 

[Letsgetitdone]

Forgot to mention the house is made from engineering bricks in the late 1950s on a council estate. Any advice on what the mortar is and general repointing tips when the perp joints aren't uniform widths would be super appreciated.

 

[CBW]

Sharp/grit sand? Looks similar to concrete.

 

[ree]

OP,
Yes, as above, some kind of, maybe local, grit sand was used with lime.
So point up with a 3:1 sand & NH lime mix.

 

[Letsgetitdone]

You guys are heroes! Yes that mortar is tough stuff reminds me of cement too honestly had me confused as to what it is. Was thinking of getting it tested to find out but ouch it's expensive.

 

[Charlie George]

You guys are heroes! Yes that mortar is tough stuff reminds me of cement too honestly had me confused as to what it is. Was thinking of getting it tested to find out but ouch it's expensive.

The chances are it is sand and cement, as lime mortar was rarely used in the late 50s.

 

[Letsgetitdone]

Well the mortar doesn't really fizz when I spray it with white vinegar, there's a very slight almost not noticeable bubbling abit like something that's parched and soaking it up rather than a fizzing if that makes sense. So you may be right, bit of a tricky one, hopefully Woody will chime in......

 

[stuart45]

As Charlie said, most 50's construction used cement mortar with lime added as a plasticizer. Sand/cement mortar is not very workable without lime or plasticizer added. Building sand looks like in the photo once the surface has weathered. A course sharp sand would be hard to work with.

 

[Letsgetitdone]

I'll pop another photo up on Friday from a section that isn't weathered.

 

[Letsgetitdone]

None weathered mortar pictures

 

[stuart45]

It still looks like cement/building sand. The reason you can't see the larger grains is that when you joint up with a metal tool it brings a cement laitance to the surface. That might have been repointed in the past. The style is weather struck, and done with pointing trowels.
Here's some steps I did about 15 years ago with building sand, and you can see now it's weathered it looks like yours.
You need a left handed bricklayer to match it.

 

[Letsgetitdone]

Thanks for the info, there's only about 2m of pointing that's in good condition where you can tell it's weatherstruck pointing. The rest of the house has pointing that's worn away. I think since I'm doing the pointing myself and i'm right handed I'll do the whole house flush pointed or bucket handle style including the 2metres of stuff that's still in good condition.

 

[Nige F]

poster ~ 4 is the lime king he lives in America in a dinsey land

 

[Nige F]

Hi just getting ready to repoint my house. I'm not sure if they've used lime mortar or sand and cement. I've attached pics showing white flecks in the mortar which don't really fizz when sprayed with white vinegar. Anyone got any idea?

those look like small lumps of neat cement - back in the day it was hand mixed -sometimes lumps would occur in the paper bags ( 1 cwt. each ! )

 

[Letsgetitdone]

I'm leaning towards it being sand and cement. Internally the walls seem to be rendered in the same stuff with a smooth surface coating of what looks like cement to me. light grey in colour a few mm thick and easily cracked.