Hello good people i have a job to quote which involves tiling an asphalt roof.

There are a number of issues to deal with and need your fellow expert opinions.

I haven't physically looked at the job yet, just getting email info and pics (see attached)

The client wants the current paving slabs removed and either replaced with slate or porcelain with a shingle border.

I have read that dark coloured tiles absorb more heat, would this affect the amount of movement, especially with the asphalt?

I had planned to put a slurry down and then use something like Fastflex.

How would you approach this job? I want to give him (and myself) as much info as poss before proceeding.

Many thanks,
Jamie.

Hi Jamie, exterior asphalt is not a suitable substrate to tile directly to. I have in the past done a few using a decoupling membrane, but things have moved on since then. Schluter do a complete balcony system, it may be a bit pricey though.

The most successful method I have used is a 65mm semi-dry screed over the asphalt, if you have the height to allow it.

Balcony and terrace construction systems - Schlüter-Systems this is it.

Thanks Phil, i think the screed would be a good idea actually as the customer just sent me this message:

The tiles (concrete slabs) are glued with what looks like to thin lines of glue. I have pulled up one loose tile and taken photo which I will email you tomorrow from work - can't do it from here. It has left an indentation in the asphelt.

I am happy to go with porcelain. I would like the tile to be at least 15mm thick, but preferably more, so that there is a sufficient dip around the edge of the terrace for the pebbles/stones.

Phil what mix would you use for the screed and do you think it would adhere to the asphalt ok? I would be worried about it cracking, but i do need to get the level up somehow to allow for the shingle.

Hi Jamie, I have used 4:1 semi-dry in the past, if you can get readymix with fiber added, you could use visqueen to act as a decoupling membrane. you would need min 65mm screed. This is just my opinion, I know it is not exactly BS but it has worked for me.

Ajax will probably shoot me down, sorry Alan

If you decide to mix your own screed and you can get hold of the fibres throw them into the mixing water, they will seperate and will lubricate them for the screed making mixing easier.

You think it is definitely best to go with fibre reinforced screed? .....and to lay it on a membrane of some sort?

Hey guys i viewed the job on Saturday and here is the latest info:

The step out onto the roof is 60mm and under the roof is the customer's lounge so i don't think a screed is a good idea.

Any ideas how i can proceed with this quote?

Originally Posted by jstrats

Hey guys i viewed the job on Saturday and here is the latest info:

The step out onto the roof is 60mm and under the roof is the customer's lounge so i don't think a screed is a good idea.

Any ideas how i can proceed with this quote?

why no screed
is there a weight issue

Taking the tile thickness and adhesive bed into consideration i will only have about 40-50mm to play with, not sure if that is adequate for a screed? The client is also nervous about me doing a screed above his living room as he thinks it may be too much weight, i'm mot sure if it is or not to be honest.

Can anyone help out with this dilemma? I don't know which way to turn at the mo.