# Forum Home Renovation Tiling  Mortar not sticking to walls!

## Sebsez

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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## AIRMAN

I think what you are trying to do is render the walls not do a screed. You will render the wall and then put a screed on the floor. For render you use a wet mix and for screed you use a dry mix. I personally find rendering quite hard on bathroom walls where it needs to be very level. 
From the sounds of it, you have the mix to dry. Try making wetter and see how you go.

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## Bloss

Sounds like the mortar was bit dry - a fine line between too wet, too dry and just right. Worth trying a commercial render mix in pre-mixed bags too. 
But . . . the real question is why are you mortaring the brickwork at all?  :Confused:  There is no reason you can't simply use tile adhesive directly onto the brickwork so long as it is clean and reasonably flat. Of course if you need to bring the face out to a new level fopr the bath etc then that's different matter. A thick-bed adhesive using a 6mm notched trowel will work fine directly onto a brick surface. Mark out the tile positions, place the bottom boards from which you will start tiling and away you go.  :2thumbsup:   
Have a read through this: http://www.beaumont-tiles.com.au/diy/index.php3  :2thumbsup:  Try again with a slightly wetter mix, but also maybe have think about simply covering the walls with fibre sheet - fast to do and a perfect surface on which to to lay tiles.

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## juan

No lime just 4 parts good plastering sand to 1 part cement. Make it a bit sloppy. Wet the wall a bit and she sticks like sheet to a blanket.  Apply with a steel trowel . 
Then leave a while to set a bit and just use the wooden straight edge to wipe it off to the same depth as your guide strips.Level off with a straight edge. Then used a wood float to get a nice smooth floated finish but roughed it up a little so it would absorb moisture later when applying the skim/set coat. 
Lay the plaster on the wall  about 15mm deep average . 
The secret is get good sand and make the mix on the weak side. Biggest mistake for us DIYers is making it too strong. We think it is better with more cement but the opposite is the case. Apparently it causes crazing later. Use 4:1 or 5:1 mix. 
Just my 2 bobs worth. 
Cheers

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## Claw Hama

I know a couple of renderers and they always put a bit of fire clay/mortar in their mix, not sure what ratio sorry. Rod the God of plastering may know more, check his web site. http://www.plasterbrokers.com.au/

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## memphis

Isnt bondcreting the wall before applying render bad news also?

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