Help with mortar repair

[600rob]

I recently had a new window fitted as the result of a badly rotted sash frame.
On the job i noticed that some areas of mortar were crumbling away pretty badly.
You might be able to see this in the pics if you look closely at the area behind and to the left of the waste pipe.

View media item 86189 View media item 86188 View media item 86187 View media item 86186

Id like to patch these areas up before they get worse but am not sure exactly what type of mortar it is and what I need to use for the repair.

could anyone help to identify what type of mortar has been used on the brick work shown in the pics.

Also is there a ready mixed or off the shelf product out there that I could use for small repair jobs like this?

Was looking at this stuff but im not not sure if it is the exact stuff required
http://m.screwfix.com/p/lafarge-tarmac-ready-to-use-mortar-5kg/96810


Any advice welcome
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[Burnerman]

That should do just fine.....if the colour matches, or that's not an issue!
John

 

[Flyboytim]

Your London yellow stocks have been re-pointed in a weatherstruck style with a mortar that was almost certainly Portland cement and sand. What could have been a small window has been bricked up with reclaimed bricks (note soot staining) in a different coloured cement and sand mortar, with indifferently horizontal courses.

Originally, with the age of your building being pre-1910, I'd guess, a lime and sand mortar was the original building material. Years of rainfall through the polluted Greater London air have eroded the exposed mortar beds, and ideally a soft lime-containing repointing mix should have been used for repairs.

The problem with using a strong cementitious mortar and soft bricks such as yours is that the pointing falls out over time, removing the adherent edges of the soft bricks. To redefine the brick courses the Weatherstruck style of pointing is used to make the brickwork look good, but in time it will damage the bricks even more. Folks then often choose to disguise the damaged brickwork with paint or rendering.

Due to the difficulty of raking out, and then re-pointing behind the pipe (and probably its likely cast-iron predecessor too) there are several gaps in the pointing in the corner shielded by the pipe.

So your best choice is probably to unclip and dismantle the pipe, if possible, for access to the wall behind to remove old mortar and re-point with your choice of mortar - either the softer lime mix, or the easier and cheaper to obtain cement and sand mortar that matches the existing re-pointing.

 

[600rob]

Thanks flyboytim for the response. I will displace/remove the pipe and go about the repair job

I'd like to get some soft lime mix mortar but am unsure of anywhere to get it and the exact mix that I require.... Are you able to recommend a brand/seller where I can get some?

Cheers

 

[Flyboytim]

I'd suggest you do some homework with Google or other search tools:
Lime Mortar Mix is a good starting point. It's a growing market, and the products should be comparable from the various companies selling them.

Considering the somewhat "hidden" area that is being repaired, a tub of ready-made lime mortar, however light in colour, will do the job, and will not look too out of place behind the pipe once replaced.

It is always possible to use some ingenuity in disguising building materials to match weathered building materials in-place. One inert additive to darken lighter mortar to match older, grey beds is crushed charcoal. Rust powder or crushed bricks can add red and yellow tones, and can be brushed onto almost dry mortar beds to stain them, as can acrylic colours from the can or tube, diluted to match.

For instance, I've used black boot polish to darken new replaced Marley roof tiles and dabs of white and yellow emulsion to imitate lichen and other natural markings on roofs to blend in, and not look like new work.