Importance of breathable paint

[anthony12uk]

I have just purchased and moved into an Edwardian terraced house. We have been in the process of de-wallpapering and I now have a room with two bare internal walls (not external facing - one is bordering the neighbour, one is bordering the stairwell). I have been researching breathable paints as the walls are the original lime plaster. Two questions - firstly, can a general all purpose filler be used to fill imperfections in the lime plaster or could this cause issues? We have a plasterer coming tomorrow and I don’t want him to use a material which could damage the walls. Secondly, how important is using breathable paint? There are no clear damp issues and the house is well ventilated due to having a Vent Axia PIV system fitted which prevents moisture build up. I don’t want to damage the walls but breathable paints are surprisingly expensive. The room is also a study, so does not have much moisture. The bathroom on the other hand which does have a lot of moisture, has been wallpapered head to toe and covered in damp seal paint so not sure if we need to strip that all back as I assume the plaster here is lime too (other than around the window as when new windows had been fitted previously they’ve all been done with gypsum).

 

[Stevers]

Breathability is a spectrum. Flat matt emulsions (for example F&B estate emulsion) and contract matt emulsions (cheap as chips in white and can be coloured) are on the breathable end of the spectrum, and I'm happy to use those anywhere. Neither are really wipeable particularly contract matt - which is a good sign.

 

[Glenn586]

firstly, can a general all purpose filler be used to fill imperfections in the lime plaster or could this cause issues? I don't think you will get any issues using a non breathable filler to fill imperfections. I'm guessing that it will make up such a tiny amount of the overall area of the wall you wont be compromising it's ability to breathe. I would recommend adding sand into the filler to give a it a rougher finish if required which may better match the lime plaster.

Secondly, how important is using breathable paint?
It's difficult to say for sure as every walls situation is slightly different however it would be a shame to compromise an already lime plastered wall for the sake of £30 or so. I only have experience with the Earthborne Claypaint range and what I can say for sure is that it's by far the most user friendly paint i've ever used. This means that while the Mrs thinks I'm still painting I'm really in the local having a few pints of my favourite tipple, to me that's £30 well spent!

 

[mh12]

Pertinent topic. Google search reveals for a paint to be classed as breathable essentially it needs to have a SD value of less than 0.50.

Whilst the specialists manufacturers in this field - Earthborne, Farrow and Ball, Limewash fulfill this criteria I dont know if any of the main paint manufacturers- Dulux, Crown, Letland etc have any paint products that would be classed as breathable?

I think Tikkurula paints also satsifies the breathable criteria.

Yes in terms of price looking upwards £90 for 5 litres for a breathbale paint option from the specialist but I suppose its hopefully a one of buy for many years so well worth it.

However if there are more cost low SD value cost effective options than it would be good to know.

Stevers you mentioned 2 options , would you have know what the SD value of these are please.

Thanks

 

[Stevers]

A breathable paint might be considered to have an SD below 0.05. This site quotes 0.02 for F&B Estate Emulsion, and that's a figure I've seen quoted elsewhere. Contract matt emulsion is going to be in that ball park along with other flat matt (non-vinyl) emulsions.

Lot's of good experience of using Multi-Purpose Polyfilla in powder form. Google seems to think it's calcium carbonate (chalk) with a synthetic (acrylic) binder, and that doesn't bother me on the breathablity front when used as a filler.

 

[Kearn]

SD values are misleading. Lab tests, minimum permeable thickens, and they measure moisture vapour transmission. Old houses need to break with actual moisture, liquid form. Pretty much all of the above won’t do that very well… if you actually need moisture to leave the generic, you need something that can allow that - genuine silica paint, distemper, lime wash in ascending benefits.

Equally, managing airborne moisture which will condense, is also important from us living in these properties. Particularly bathrooms, kitchens, bedrooms… then your walls will absorb the moisture and slowly release it.

Small cracks, just use polyfilla, small areas won’t make a difference.

 

[mardinor]

Unsolicited advice, learnt the hard way: those de-wallpapered walls are likely to still be covered with paste residue. Any paint will bubble. You MUST either wet the wall with a big sponge then scrape the residue off with a wallpaper scraper, or cover it all with Zinsner Gardz. Decorators will do the latter, but it ruins breathability. So do the former.

PS Breathable paint is important and tends to also look much nicer. Suggest F&B estate emulsion, Earthborn Clay paint or Aura.
PPS The cost of paint becomes a rounding error compared to a plasterer...

 

[Stevers]

Unsolicited advice, learnt the hard way: those de-wallpapered walls are likely to still be covered with paste residue.

Another reason to use a lining paper before painting. Not a fan of the process, but I do appreciate the result!

 

[Janela]

Mike Wye claim earthborn clay paint is 'virtually' as breathable as limewash and is simpler and quicker to use.
I've used it for about 10 yrs now and it is a real pleasure to use.
I bought it for lime plaster but now use it on all wall surfaces. Smells great (no headaches). Easy to tweak the colour.
It is much thicker than other paints so you only need a very watery base coat then one top coat. This thicker texture also covers and fills imperfections - great for those of us with room for improvement in our plastering skills.

It isn't, however washable and doesn't like wine being spilt over it!!

I don't think it's worth risking compromising good plaster with the 'wrong' paint though.

 

[mh12]

Mike Wye claim earthborn clay paint is 'virtually' as breathable as limewash and is simpler and quicker to use.
I've used it for about 10 yrs now and it is a real pleasure to use.

Thank you all for the input.
Janela, need a product which is going to be touch and child friendly and not leave imprints when touched, and last not quite the test of time but a good few years.
In your experience how do the earthborne clay paints perform in this regard? Any imprints/fading of the paint upon touch.
Thanks

 

[Stevers]

I don't think it's worth risking compromising good plaster with the 'wrong' paint though.

Another advantage of lining paper!

 

[Kearn]

Thank you all for the input.
Janela, need a product which is going to be touch and child friendly and not leave imprints when touched, and last not quite the test of time but a good few years.
In your experience how do the earthborne clay paints perform in this regard? Any imprints/fading of the paint upon touch.
Thanks

This is where some of the ‘leading’ suppliers are losing credibility. They know full well, it is not a patch on limewash. There is clay in the ingredients, so the terminology is allowed, but not that much and they use synthetic binders.

Earthborn isn’t bad to use, and on internal walls or those that don’t need to do lots of moisture management it isn’t bad. While it’s not brilliantly wipeable, it can be carefully touched up to deal with marks.

 

[Janela]

I Dont think it would easily show fingermarks (assuming the fingers aren't covered with jam!) We have a lake and Chesapeake Bay retreivers who live half in the lake and half in the house and the walls cope. As Kearn says it is paint that can easily be retouched, I go round sometimes with a brush and a can and just brush over any marks and the retouches don't show.

I do agree too that limewash will handle damp walls better. If you want darker walls however it is difficult to get with limewash.

 

[Kearn]

I do agree too that limewash will handle damp walls better. If you want darker walls however it is difficult to get with limewash.

Limewash can be coloured, but mixing pigment evenly is tricky! And it’s only ever a heavy tint due to the lack of binder.

Distemper on the other hand can generate some lovely, deep colours.