Paint removal from brick, stonework or timber is a very specialist service and when appointing a contractor to carry out this work you must be very careful as a lot of damage can be caused if the wrong method is used. There are a few systems available on the market
- Media Blasting (Commonly known as sand blasting)
- Chemical stripping
- Doff (High pressured steam system)
- Torc (Combination of media blasting and pressure washing)
The selection of the right system will depend on the following:
Whether the Paint Removal is Internal or External
If the job is internal then the use of any system which introduces water may be out of the question. So in that circumstance, media blasting or chemical stripping may be the only systems possible. Please make sure the chemical used is authorised for internal use by the health and safety executive and manufacturer.
Is Dust an Issue?
Are there any entrapment issues, content issues or environmental health issues? If dust is an issue then Doff, Torc, chemical stripping or Ice blasting will be the preferable options.
The Type of Paint Being Removed
If the paint is lead based then chemical stripping would be the preferred system. If it is lime based then the torc system will be the most effective. Doff is most effective exterior and internal paint coatings.
The Effect You are Looking for
Some people like the effect of media blasting on internal walls because it creates a texture to the brick and pointing and with the paint specks left it gives a patina which makes the wall a feature. The doff and Torc systems will remove the paint without damaging the brick so you get a clean brick look.
The Listing of the Structure
English heritage will not allow media blasting and pressure washing in most circumstances. They prefer lighter systems which cause the least amount of damage to the structure. The Torc and Doff system are the most approved systems in listed buildings.
The Condition and Hardness of the Structure Below the Paint Work
The rule is that the media used should be softer than the structure below or it will damage the structure. The problem with paint removal is that the paint is sometime harder than the surface below particularly when over the years you have multiple layers of paint.
If you choose the media for the paint you will not know at what point you have reached through the paint and are now damaging the structure. The best systems in this situation are the softer systems such as Doff and Torc.
We would never advise aggressive media blasting for paint removal on external walls as any damage to the bricks could make them porous leading to water ingression.