Primers - what to use and where

[primetime]

Hi all, long time reader, first time poster.

I have a few projects planned and have searched on here and further afield and got some conflicting/confusing answers. I have the scenarios below and would like some advice, mostly on what primers to use or can be used. I have access to all the usual Screwfix, B&Q, Topps, Tile Giant, Selco etc.

1. (Not tiles) Exterior brick chimney i'd like to sand and cement render because of spawl and associated damp. Which primer would be best for this?
2. Flat roof bathroom has concrete slab floor with vinyl tiles currently. I'd like to electrically underfloor heat and tile but before doing so I want to level one corner with sand and cement. What would be the best primer for concrete on concrete? The existing concrete is in good condition. I plan on sweeping and cleaning with water first.
3. Backer board. I'm planning on 6mm backer board in the bathroom and use flexible tile adhesive. What should I prime the concrete with before the backer boards go on?
4. I plan on laying the UFH and using a SLC to cover. Which primer should then be used over the SLC before the tile adhesive and tiles?

Thanks.

 

[primetime]

Thanks for the suggestion. I've been looking around to see where I can get it. Have also come across Cementone SBR. Would that be suitable?

 

[AtlasTony]

It may be suitable for the projects involving concrete or mortar, as from what I gather it has been specifically designed for that. But as I haven't used it myself I couldn't say whether it would be suitable for all of your projects.

Personally I use the Weber, it is the one primer that I have not had a problem with on any jobs I have done, whether I have used it on tanking, tiling, screed levelling etc.