The usual start is to look at the sources of the damp. Showers, roof leaks, boiling food at excessively high settings, all can be much improved in many cases. Theres also dehumidifiers, which work out cheaper than ventilation, though some vent is of course needed.
NT
Cement does not inhibit porosity - your problems start if they have mixed in Sika or similar. In any case, as someone wrote, Limelite contains lime.
Maris
It was never cheap!
Maris
I read the page and it doesnt say the opposite at all, it confirms its cement based, as you just have yourself. It also confirms its lack of breathability.
Lime and sand are =A36 and =A31-2 a bag respectively, and will not do the long term damage to soft brick and stone that cements often do. Being genuinely breathable they will allow evaporation, which is enough to keep most damp walls dry. To maintain this evaporation of any dampness one should avoid non-porous coatings such as emulsion, instead using distemper or similar.
I could talk about the use of EML and its effects on cracking, but enough for one post. In short one should not assume that everyone claiming conservation expertise actually has it, nor that what they do have is sufficient to choose the best options in any given situation. Even today there are still companies cement rendering wood framed buldings.
NT
Someone is going to pull us up for off-topic soon (well uk.legal, anyway)! Just found a very useful thread discussing the various plastering options on
Where did you see the bit about lack of breathability? All I can see in the item referred to is designed to 'control damp passing through walls'. Are you assuming that means blocks it entirely? Had a more in depth look at the
Wrong. Avoid vinyl-based emulsion. My lower ground floor problem room is painted with this crap and it's a bugger to get off.
Maris
elsewhere, cement based renders have too little porosity to be realistically described as breathable.
heh, its one of those topics that never ends.
I thought thats what I just said :)
NT
yes it does
even worse
and cement. Cement content reduces water movement. Cement lime mixes do not have anywher near the porosity of lime mortars.
Ask SPAB or period property forum etc about ime and cement.
NT
Breathability and porosity of cement based mortar depends on the cement strength. At 1:6, there's no problem, but you need to add a waterproofer to prevent the pores also wicking water through. (Contrary to what you suggested, this won't work as tanking, as any significant pressure of water will pass through the pores regardless of their water repelling coating.)
Matt emulsion is breathable (vinyl isn't).
Enough of it does..
- your problems start if they have
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