Gaps in mortar

[Iain]

We are still moving into the new spread with a total internal rebuild required, that is not a concern but on the outside some of the mortar has vanished making the bricks look a bit like Chad MOrgans teeth.
This is confined to one area and I need to get some mortar back.
I think that all I need is to trowel some mortar back into the cracks and as we intend renedering I am not concerned about the overfill.
Is there a right or wrong way of doing this, the problem is not structural (yet) and is confined to a random selection of bricks on one wall, a total of about 20 bricks are affected.
Also, what makes the mortar go powdery like this lot has, wife thinks it is some sort of insect but I am not sure.
House is about 50 years old and generally sound.

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[Eastie]

Iain,

Scrape out the old mortar from in the crack around the bricks and remove a couple of inches of render from either side of the crack. Doesn’t sound like it needs any reinforcement so you should be right just bagging it with new mortar.

If colour is an issue, good luck.

Stick with a good quality render and talk to the supplier about if a little bit of lime mixed in will be ok. Chances are the render (50+ years old) is just lime with sand and a tiny bit of cement.

It chalks up like this due to aging weather – makes no sense seeing as the rest of the house is exposed I know http://ubb.ubeaut.com.au/ubb/biggrin.gif
The crack would be due to minor movement - shouldn't need to worry too much.

Good luck.
Eastie.


Oh yeah, if you simply trowel more into the existing crack without removing 2-3 inches around it and scraping out the mortar it will simply crack again.

[This message has been edited by Eastie (edited 21 October 2002).]

[Iain]

Thanks Eastie, will give that a go, the mortar is mainly missing from the verticals rather than the horizontals but will remove a bit either side as reccomended and attempt the fill.
In some sections the mortar has gone completely leaving a hole through to the inside wall!
As I said, this is only on a few and doesn't appear to affect support in anyway as it is random and bricks above and below are all sound.

[Gino]

Iain.

Make sure you totaly clean the surfaces of the brick which the new mortor will be applied to.
I reckon this happened because not enough cement was put in when it was done (I think)

When I did the same to my bothers place I was having problems making the new morter stick, Mum happened to be there and said that her dad used to wet the surface first before applying the morter. So once I did this it worked well.
You can splash it on or use a spray bottle to do the job.

regards

Gino

[JackG]

I found out (the hard way) that rendering is an extremely difficult task and after a few not too sucessful attempts I was told to add a little bit of renderers clay and a tiny bit of dishwasing liquid in the mix, it made it a lot easier.

Jack

[Iain]

Thanks for the tips and will heed them all and speak with a brickie, Gino, the wetting I did know, and that was about all I knew.

[coastie]

Ian:Get yourself a thing called a caulking trowel,has a normal handle but the blade is only about 10mm wide, it's used for repacking mortar back into joints.Your problem could have ben caused by ants etc,especially if the original mortar was too sandy,also get a pointing trowel, on which to put the mortar once you have mixed it,just go steadily,working a small section at at time,have fun!

[soundman]

queensland cement & lime have a real good booklet about cement and mortar & so on discusses mictures & application available by phoneing them.

the NO 1 reason for any cement failing is inacurate mixing!!!

cheers.