valley mortaring disaster

[DIYedboy]

I am trying to mortar up beneath the cut tile edges as I fit them up a fibreglass valley. I am using wickes sharp sand mixed 3 to 1 with a brand new bag of blue circle mastercrete. The mortar varies from one inch to three inches deep as it conforms to the profile of the tile. I have left the mortar for 2 n a half hours to let the mortar stiffen up but although it has stiffened it still falls away from the underside of the tiles where it's 3 inches deep, it's a warm evening so I assume the mortar aint gonna stick! What have I done wrong?

 

[tony1851]

Probably dried out too quickly; on a warm day, the tiles can be hot.

 

[DIYedboy]

I was wondering if I should add one part soft sand cos that makes the mortar more sticky
OR add SBR into the mix
OR add concreting fibres to give reinforcement and stop the slumping

What do you think?

 

[noseall]

Bed tile 'slips' into the mortar where thickness is an issue.

Experimenting with the sand mix shows you are clued up. Whilst too much soft sand leaves the mortar prone to cracking it does make it more workable.

You need to only add enough water to make the muck useable. Bed the tiles then drag back the mortar so that you are kinda hollowing out the steep wall of muck and leave it rough and leave it to stiffen.

Then go back after a wee while and add some more (workable stuff) onto the rough stiffened stuff.

Imagine doing it in the winter.

 

[DIYedboy]

Cheers Nose, my mortar was quite dry to try n combat slumping, yeah, trying to do this in winter you'd need to wait 2 days for it to stiffen! What a shame foam filler ain't weatherproof!

 

[shane12345]

Best way is to back bed the tiles on with mortar.

Leave it overnight and then you can fill the rest of it up and the mortar will have something to key to. As it is at the min you are probably not pushing enough in.

 

[noseall]

As it is at the min you are probably not pushing enough in.

Ooer missus!

 

[DIYedboy]

Thanks lads.................I've just done me back in, can't even get me pants on, so roofing is definitely out! what a bummer