I'm going to be sending of some mortar taken from a Victorian house for analysis, the company should be able to find a match. Looks like a mixture of ash an lime was used to be the bricks (ash like substance), then repointed with lime mortar. Probably due to costs.
Disaggregation analysis of lime mortar, the price varies widely for the testing. Years ago, I got arrested for having a large 1.5kg bag of white powder, which was found by a young wpc in a inside pocket in my coat during a routine traffic stop while out on my motor bike, she was adament it was cocaine. Eventually got released on bail after many hours in custody, pending further investigations, this wpc had visions of promotion to a sargent,or higher with that find, rather ruined her week, when the results came back & it tested positive for Tetrion Filler. Couldn't fit the box inside my coat, so I removed it & doubled bagged the filler so it fitted in the internal pocket.
Conserve said they would carry it out for free, once it's on their system, I can order the same mix again in future. The bedding mortar is very soft, almost like ash. Victorians used coal fires and the waste was most likely used in the mix.
Good deal. They used anything in their mix even furnace s lag, clinker,ground down to various grades from a course to fine powder. Pozzolana ash, otherwise known (volcanic ash) was used by the romans & several countries in their mortar to improve it's performance.
There's bits of chalk in there as well. Looks like the bricks were laid on the cheaper material, then lime mortar used to point over. Some of joints are so weak that you can stick a screwdriver in there with little force, and become powdery.
Nothing surprises me, quite common in the Victorian/Edwardian to jerry build things (is that word allowed now). Did a old wall years ago, it's builder had laid two narrow beds of lime mortar each about 30mm wide just along the edge of the bricks, nothing in the centre of the brick, yet it hadn't fallen down in about 80 years, this was only found when the lime plaster was removed & wall started bowing, ended up rebuilding wall. Hopefully you will just get away with repointing?
This is what I'm doing at present. The brickwork below the plinth bricks were all rendered in straight cement, and have spend 2 days carefully chipping away at it, some has lifted off neatly, there has been some stubborn parts as well. Had to use club hammer and bolster chisel/paint stripper (with hammer head) to remove it all, some bricks have worked loose so need to reset some areas. Painstaking job to remove without trying to ruin bricks. The repointing above the plinth, although neatly done is cement as well but not going to touch this. Also noticed now that the clay drain bend for the RW has a crack in it, which would explain why the bricks on the other side have deteriorated more. They are hand made bricks so are pretty expensive (£1.40 each) from reclamation yard. Not sure where the RW leads to but there are cast iron gulleys located on the pavement may get a CCTV inspection, but need to find a someone who can do it as most equipment wont go down 3" pipe.
You can have cctv drain survey done for pipes small as 50mm, some firms will even do 25mm pipes. I did one myself a few years ago, you can hire the equipment, from hire shops like Speedy Hire. The Scanprobe cctv came with a 35mm camera, but smaller camera were available.
I hope so, some of the point has become dust like very scary. May have to do small sections at a time and go in deeper, Ive got one of those pointing guns so will try this, didn't have much luck earlier as the mortar wasn't squeezable, but with a lime putty may be able to get it to go deeper into the voids. Should get the sample tubs next week.
My little repoint job: Reopinting is mixture of cement and originator lime mortar. Received 10kg sample, tried on small area: Before Pointing already loose, exposing bedding Mortar applied wet Finished - Dry
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