In our experience the two biggest culprits of damp in old buildings are cement and modern, synthetic based paints, so if your property is built in the “traditional” manner, as solid composite masonry, and suffering from damp as a result of modern paint coating/s it could well be that stripping the paint may be the only realistic option open to you. What can be said about paint stripping other than for most people, it’s not a job it’s a sentence; as for the rest, they simply avoid it. There are a number of processes for removing paint from masonry walls and each one should be weighed up on its own merits and approached as an exercise in risk/benefit. Regardless of what the paint or surface coating is, the objective will always be the same, to get back to an appropriate surface using the least damaging method available with minimal risk to the operator and surroundings. For information on cleaning methods, outside of paint stripping, see our guide to cleaning rendered walls, stone masonry & brickwork.
Methods of Stripping/Cleaning
The method of stripping paint will fall into one of two basic categories, either chemical or mechanical methods. Mechanical Methods include grit/blast cleaning, high pressure water jets, steam cleaning, wire brushing, needle gunning or other methods involving mechanical abrasion.
Grit/Blast cleaning
Grit/Blast cleaning uses a range of wet or dry systems with a wide range of abrasive media, from very coarse gritty materials through to fine talc’s, even nut shells. However, water/air-abrasive systems, even at low pressure can all too easily result in damage to the surface beneath, particularly soft brick and stonework. There are too few contractors out there who have a sufficient understanding of the damage they are likely to inflict on traditional masonry structures from an all too often heavy handed approach many have when carrying out this kind of work. Other forms of mechanical abrasion need to be carefully considered but are unlikely to be effective and nuisance free. However, if there is limewash under the modern coating then the use of an air or electric powered needle gun may sometimes be worth exploring. A needle gun is a potentially damaging tool but used diligently at a pressure to suit the material needing to be removed it can be very effective. But like any other power tool, use skilfully and with care to avoid any damage.
High Pressure Water Cleaning
High Pressure water cleaning is unlikely to be very effective, and could easily result in setting up its own problems from the amount of water delivered into the fabric; bearing in mind that water is the engine of decay. However, systems such as DOFF which rely on a combination of high temperature steam at high pressure are very effective on modern heat pliable paint surfaces; heat from the steam softens the paint, with the high pressure delivery assisting the removal of the paint film, while greatly reducing the volume of liquid applied onto the wall surface. That said from my experience the process can be messy and the equipment somewhat temperamental and as such not a cheap operation.
Chemical Removal
Chemical solutions are based on dissolving the paint with the use of chemical formulations. While these can be a very effective method for removal, there have been widespread concerns around the world in recent years regarding the cocktail of chemicals used within the differing products. Such concerns resulted in the European Union banning the use of DCM’s (Di-Chloromethane) in products sold to the public. *DCM has been classified as a Category 3 carcinogen in the European Community.
Cornish Lime stock an extensive range of DCM free paint strippers and anti-graffiti products; produced by Scheidel one of Germany’s leading manufacturers in this field, who have been producing DCM free paint stripping products since the late 1960’s.
There are many types of chemical stripper with the more aggressive potions sometimes acting instantaneously while others such as the Scheidel range, applied as a poultice, pasted onto the surface breaking down the paints binders facilitating later removal by scraper or water cleaning, normally after 24 hrs. The Company has an extensive product range to suit a wide range of paint products and our work to date with these products has been very encouraging.
Paint removal is not an exact science given the wide range of paints available or the number of coats that have been applied. As such it will be difficult to state which product from the Scheidel range will yield the best results and as such we advocate sample trials to determine the most economical outcome and the following is a brief synopsis advising how we carry out such trials.
Sample Trials
Our experience to date working with Scheidel products here in the UK to remove masonry and other synthetic paints has determined the two most effective products are the Asur and SG94. Both products are CHC-free (chlorinated hydrocarbon) and work on the basis of slowly exhaling esters and other special solvents that break down the paints binders. These two products are very different in terms of their composition, performance characteristics and price, and exactly which one or how much product will be required are almost impossible to predict and the best way of establishing a clearer indication to those two points would be to carry out in-situ trials as a control measure using as many sample areas as practically possible.
Removal of the Existing Paint
For any such sample trials we advise that an area equal or greater than a sheet of A4 paper is identified and marked out. Using a trowel apply at least 3 mm of paint remover at one end and let it run out to nothing at the other end. Cover half the control area with film (e.g. Pallet wrap, cling film etc) note date, time and temperature and check the test area at different intervals to determine the optimum application time and the products open time. If the product does not deliver the desired result, further test applications will be necessary to establish the likely number of applications. The removal of the dissolved coatings should always be done at the optimal dissolving point. The longer the treated coatings remain on the substrate, the more difficult it will be to wash them off. The removal of the paint (for the trials) will be best served by simply scraping the paint off with a flat bladed scraper/knife. If you are working externally and also looking to remove biological materials or staining, D/2 Biological Solution is a good option to consider for removing mould, algae or pollutant staining.
Once the paint coatings have been removed the surfaces MUST be washed with the addition of Powerfluid at the dilution of 1: 10 preferably with warm water, using a scrubbing brush or a sponge, once washed with the Powerfluid the same surfaces should be rinsed with clear water: Powerfluid is a detergent cleaner used after paint removal to help neutralise the chemicals. The above process is exactly the same for any of the Scheidel paint strippers being tested.
With regards to the actual consumption of the paint remover this will come down to a calculated guess from interpreting the results as finished. Alternatively, following the initial trials it may be worth considering conducting additional trials using the selected product at the optimum thickness to establish a better idea for consumption.
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The information provided by Cornish Lime is for informational purposes only and does not amount to a specification. Every project is unique, so please consult a professional before undertaking a project. Use of this site and reliance on any information on the site is solely at your own risk.
Can you send me prices for the paint stripper and the power fluid as I am unable to find this on your site. We have an old cottage which we have been told needs years of masonary paint removed.
Thank you for your enquiry. All our details on paint stripping can be found here:
https://cornishlime.co.uk/articles/paint-stripping/
If you need any further guidance please don’t hesitate to get in touch.
Do you know of any internal masonry paint which can be washed off in the future…. we have a stone fireplace surround – which we want to paint – but may wish to remove it in the future. thanks for any help
We are renovating a listed building in Trim Co. Meath Ireland. There’s about 20 coats of hard gloss paint on the lime render and stone fills. We tried sandblasting a section. Not really successful. Would you have a product that might solve this Thanks Loman
Good Afternoon
The Scheidel range of paint strippers could work, however it may take several applications and you could use a large amount of the stripper. Within the range there are 2 strippers – Asur and SG94, both will work, although one will work better but unfortunately we have no way of knowing until site trials are carried out.
Kind Regards
Adam Brown
Hi , we live in a 15 c timber framed building with the majority of walls cement rendered but a few with lime render. The whole building was painted with masonry paint. Fortunately we have not had damp problems .
However , we decided to re paint the house last year and thought that a lime wash would be sympathetic to the building.
We did not appreciate that line wash cannot be used straight onto masonry ! Now 2 walls have the lime wash flaking off but the others are mostly ok.
We have been told that we need to remove the limewash and re paint with masonry .
Can you recommend how to do this please. I have tried a small patch with a pressure water hose but only a little has come off
Best wishes
Patricia
Hi Patricia
Whilst we wouldn’t recommend redecorating in masonry paint, i do understand your predicament. To remove limewash i would recommend trying to scrub back the paint with a stiff brush or a churn brush, this should hopefully break down the paint and then it can be washed off. I would try and avoid a pressure washer as this could inject large volumes of water into the render and may cause damage to the render itself. The fact that the limewash has stuck to limewash is strange as it only usually works on mineral backgrounds. If this doesnt work we have a product called Etching Fluid, which is an acid based cleaner, it is designed for removing latence (free lime) layers before painting, it will likely remove the limewash but could prove expensive.
Kind Regards
Adam Brown
I have a job where the masonry paint on a rendered wall has peeled very badly and I want the paint removing to get back to the original render surface and then repainted properly. Can you advise of the best possible product within your range for what I am trying to achieve ?
Many thanks
Hi Julian
We have two products – Asur (https://cornishlime.co.uk/products/associated-products/scheidel-asur/) and SG94 (https://cornishlime.co.uk/products/associated-products/scheidel-sg94/). Which will work best is somewhat difficult to say as we don’t know the exact composition of the paint that is currently on the wall. I would suggesting trialling both paint strippers and seeing which is most effective for your specific application. Both products are available in 1 litre pots for sampling. Trialling will also give you an idea of coverage and the time the paint stripper needs to be left to dwell.
When it comes to the main body of work the recommended application is to use the paint stripper, remove the paint and then wash the surface with a product called Powerfluid/Ultrafix, this is a mild acid (it is diluted with up to 10 parts water before use) designed to remove any paint residues which be left behind.
Any questions please do not hesitate to contact our shop on 01208 79779.
Kind Regards
Adam
Hi, my daughter has bought a house built during the late 1800’s which is lime plastered internally,the problem being all the walls internally have been painted with modern emulsion paint ,how can this be removed so she can repaint with a breathable alternative .
Many thanks.
Thank you for your enquiry.
We would suggest that the first process would be to attempt removal using hand tools such as scrapers, but if this is not successful both the Scheidel Asur and SG94 could be used to break down the paint. These products are painted onto the surface and left to dwell, after 1 to 24 hours the coatings begin to breakdown and can be easily removed.
Please let us know if we can be of further assistance.
Hi.
We have a 400 year old cob cottage. Previously owners have painted the walls with masonry paint. We don’t have damp issues but feel we should return it to lime wash. Reading your articles this seems possible but due to the very bobbled nature of the render (a lumpy thrown application) it is going to be very difficult to achieve . Any advice ? Or are we best to leave it as it is
Thanks for getting in touch. The various methods mentioned in the article could be used although it may be easiest through the use of the Scheidel paint strippers as this will chemically breakdown the existing coatings and as its painted on you can ensure coverage over the undulating surfaces. But with any paint stripping its impossible to say how long this will take until sample trials are undertaken.
Unfortunately with removing paint there is no quick fix. If you decide to trial the Scheidel range we would suggest you take a litre of SG94 and a litre of Asur and see which product works best for you. Please let us know if we can be of further help.
Hi, we have had our bedroom re painted but the decorator used dulux matt paint on our lime walls, we have been told that this paint will damage the wall and we need to remove the paint, as this is a newly refurbished inside room how can we do this with out causing to much mess please , we have new carpets and we are also worried about the flumes if we use a stripper of any kind . Thank you
Thank you for your enquiry. Whilst we can’t guarantee against any mess as this comes down to the applicator, our paint strippers (SG94 & Asur) come in a paste/jelly form so they could be carefully applied to the wall, providing the floor is protected.
In terms of fumes our strippers are CHC free and don’t contain a lot of the nastier chemicals found in the conventional strippers. We would always recommend keeping the room well ventilated when using them though.
My husband and I unknowingly painted our plaster ceilings with latex paint that were originally painted with a lime silicate paint. Now our paint is peeling in some rooms others it seems sound but we’d like to remove it.
For the rooms peeling, a wall paper steamer and air compressor is removing the majority of the paint but the rooms that are sound are unresponsive to the steam.
We’d like to remove the paint and reapply a lime Silicate paint.
1. Do you have any suggestions to remove the paint that is not responsive to steam?
2. Is a wall paper steamer dangerous to use on sound plaster?
3. Once we remove the paint, is there a possibility the lime paint won’t adhere due to the latex once on it?
Thank you for your enquiry. In terms of removal we do have a range of paint strippers which could be used –
https://cornishlime.co.uk/products/associated-products/scheidel-sg94/
https://cornishlime.co.uk/products/associated-products/scheidel-asur/
Both are designed to breakdown the paint and enable you to peel the paint off.
Unfortunately it is difficult to say whether a steamer will cause any damage as every plaster and application will be specific, but in terms of moisture the plaster should be able to accommodate this.
There is a risk that paint wont adhere, however this will depend on the paint itself. So, for example a limewash or lime paint may struggle to adhere if any paint or paint residues remain, but a mineral based paint such as Beeck Maxil Pro should adhere fine – https://cornishlime.co.uk/products/breathable-paints/beeck-maxil-pro/
Please let us know if we can be of further assistance.
Hi we recently moved into a 17C grade 2 listed farmhouse. We want to redecorate some rooms, one of which has a low salt ‘tideline’ following an incident with blocked drains during heavy rain. This has taken the surface paint off and I think that the plaster underneath is lime – it looks white. My questions are as follows: how can I tell whether the existing paint on the walls is breathable / suitable to be painted over? If it looks like non-breathable paint has been used, what is the best long term course of action – remove the existing paint? Do I need to do anything to stabilise the salts before repainting? Thank you.
Thanks for getting in touch. It can be very difficult to tell whether the existing paint is ‘breathable’ unless you can remove a section of the plaster for testing. If the paint can be peeled at all is usually a sign that it is not suitable and sometimes if you photograph the wall during the day but have the flash turned on, it is sometimes possible to see a shine or sheen from the paint in the photo and this is usually a sign of the paint being film forming and not suitable. Removing the existing paint is an option, it then depends on what the plaster actually is.
Unfortunately, there is no way to stabilise salts within a lime plaster and/or to retain breathability, as salt is soluble it can transfer through the plaster and crystalise on the surface, as salt has an expansive force of 2.1 tonne per m2 no stabiliser will be able to prevent this. The best remedy is time, if you feel confident you have addressed the source of salt and moisture is able to transfer through the wall it will eventually escape. How long this will take is somewhat unknown, as there is no way of telling how much salt is within the wall.
If you could send us pictures of the walls we may be able to better comment. Please forwrad them to adam@cornishlime.co.uk Many thanks
Enquiring from Ireland, I left Cornwall a few years ago but could come and collect materials next visit. I’m hoping to remove one layer of magnolia vinyl paint from all the C18th dark pink and dark blue lime wash without damaging it. Help! Some is coming off in sheets but a steamer will ruin the chalky original, I’d be grateful for any advice.
Thanks for getting in touch. We have two paint strippers, Scheidel Asur and Scheidel SG94, both will work. We would recommend trial samples of each are undertaken to gauge which product is most effective. As a general rule, we do usually find that the Asur is more effective though. Please let us know if you needed anythign further.
Hello,
We have a brick wall in a 18th century house which we had lime plastered and then painted after 6 weeks with clay paint which is supposed to be porous and recommended for lime plaster. The paint has been flaking off for the past 3 years and it appears as though salts are coming out of the wall. We want to redo with lime-wash. Can you recommend the best method to remove the clay paint? Someone suggested putting up plastic coverings to make the damp worse so that the paint will come off in sheets. This is what has happened behind a court cupboard in another room because of the lack of air flow and increased damp – the paint has come off easily there. Thanks
Hello, I have just bought a house built in the 1800s. I would like to re paint the walls using eco, breathable paint. I presumably have to first remove the old emulsion that the previous owners used. I have seen your reply to Doreen (July 2020) above but my question is, what should I do if the walls have been plastered with modern plaster? Should I remove the plaster and replace with lime plaster or would that be a waste of time? Thank you
Thanks for getting in touch.
As long as the paint is sound (well bonded, no flaking etc.), certain paints can be applied directly over the existing paint – such as Beeck Maxil Pro.
By using such paints you will still get all of the environmental benefit, but if overpainted modern paints and then modern plasters you will not achieve the breathability. To achieve this you would need to consider removing the paint and/or underlying plaster – which is a much bigger task, but will ultimately offer the greatest benefits long term.
We have lime plaster/ render internally with what I assume is a lime finishing plaster (it’s about 2 mm thick) over the top with lime wash or distemper on top, from the 1920’s.
So a gritty inch thick render over brick with a 2mm chalky layer and coloured dusty paint. Is the 2mm layer limewash? The paint is resilient marginally to water and scrubbing (by no means as much as latex would be), enough to mean scrubbing the whole area to get the paint off removes more of the render between as it’s softer. Should we scrape back to the render and then lime wash? We are trying to avoid lining paper.
Also do we absolutely need to avoid cheap DIY shop emulsion? We cannot paint over the flaking limewash as it would be a mess…so either:
Scrape back to render and paint directly onto that.
Lime wash onto the peeling distemper/ limewash (is that possible) to get one finish, then paint.
Try to somehow smooth the current finish with some sort of polycell smooth over type roll on paint repair…
Hi,
I have an 1860’s listed harled (roughcast) building in Scotland. It has been painted with Sandtex masonry paint. I have re-harled some walls with lime, so now have two finishes, new unpainted lime and Sandtexed old lime (though it may have some early cement in it). Is there any advantage to painting both types of surfaces with a breathable paint? Another part of this building has already had a coat or two of Dulux Weathershield over the Sandtex.
Thanks for getting in touch. We would recommend the Beeck Mineral Paint for your property. It will provide longevity, durability and consistency across the different backgrounds. Renosil will work with previously painted surfaces as well as being vapour permeable on the lime background. It will provide a more uniformed finish and better match overall for you.
You can read more about it here: https://cornishlime.co.uk/products/breathable-paints/beeck-renosil/
Hello
We have a grade 2 listed 17th century cottage with cob & stone walls. Around 2 years ago we painted the lounge with standard matt emulsion which was a mistake. Parts of the wall are now showing signs of damp. I think I need to remove all the paint on the interior of our lounge and start again from scratch using breathable paint. Is SG94 the best option for paint removal ?
Hi Kevin
We have two products – Asur (https://cornishlime.co.uk/products/associated-products/scheidel-asur/) and SG94 (https://cornishlime.co.uk/products/associated-products/scheidel-sg94/). Which will work best is somewhat difficult to say as we don’t know the exact composition of the paint that is currently on the wall. We would suggesting trialling both paint strippers and seeing which is most effective for your specific application. Both products are available in 1 litre pots for sampling. Trialling will also give you an idea of coverage and the time the paint stripper needs to be left to dwell.
When it comes to the main body of work the recommended application is to use the paint stripper, remove the paint and then wash the surface with a product called Powerfluid/Ultrafix, this is a mild acid (it is diluted with up to 10 parts water before use) designed to remove any paint residues which be left behind.
Any questions please do not hesitate to contact us on 01208 79779.