Mortar not sticking to walls!

Hi All,


I am preparing my bathroom walls for tiling at the moment.
I have just finished removing all the old mortar off the walls so they are bare brick.
Now it is time for the tricky bit... laying a new mortar bed!

I thought I would do a test run first of all... I failed misserably!
The mortar would not stick to the wall !

This is what I did, I was wondering if someone could tell me where I have gone wrong?

1. Gave the brick wall a quick sand to get rid of any loose bits of mortar.
2. Gave it a dust off.
3. Mixed up a 1:5 mix of bondcrete : water and brushed this onto the wall.
4. Mixed up a 4:1:1 mix of sand:cement:Lime.
5. Mixed the mortar mix with a bucket of 1:5 bondcrete : Water mix.
6. The mortar mix was a clumpy texture.
7. Started applying the mortar to the wall with trowel.... some would stick, some would fall off.
8. When I started screeding the mortar it just started coming off in huge chucks!

Is my mortar mix not right?
Should I have waited longer before screeding?
Should I put mesh reinforecement on the wall first? (To help the mortar hold)

Any pointers would be greatly appreciated!

Thanks


Seb


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