Flat concrete roof, Waterproofing the exterior with Thompson Roof seal,
Repointing interior and exterior walls, Prior to Painting brick with Sandtex, I’ll wash down with a stabilizer,
Question is, What can I paint the interior brickwork with?
I want White walls to make it bright, If I paint with Sandtex exterior paint inside and out, will the walls be able to breath and allow any moisture evaporate?

Any help/advice would be welcome!

lime wash on the inside?

and outside.

Lime wash? Doesn’t seem to be readily available? Am I looking for something else?
Even looking for bagged lime to make it up is not on your Wickes.co.uk or diy.com.

this?

You can just use emulsion. You need some airbricks though to keep it properly dry, otherwise there is a good chance of mould occurring.

Lime is a good alternative but can flake over time.

Ty-mawr specialise in lime based paints and renders. If it’s single skin brick it’s unlikely to stay properly dry but that will depend on exposure to driving rain.

You may also need a ‘proper’ flat roof material to a nominal fall rather than just sealing concrete. Felt or fibreglass would be the easiest options depending on whether you want to do it yourself or get someone in.

Batten the walls and clad the outside with shiplap. Batten the inside and insulate and line with ply.

Sorry forgot to mention I’m trying to keep the costs down!
Shiplap would look awesome but financial restrictions mean this will never happen!

You could paint with Cementone Aquaprufe – 3 coats painted on in alternate directions. Whilst the last coat is wet blind it off with plasterers sand (throw sand at it) it can then be painted with any colour paint you want as the sand will give it a key for the coloured paint of your choice. You will need a few coats of paint to cover the black bitumenous paint but it does work and is fairly cheap.