Brick Cleaning.
Surface Preparation – Nationwide
Dirty Brick Cleaning – Sand Jet
We can clean dirty bricks, or remove paint from them; we have various techniques or options for this depending on the dirt or paint, and the quality or softness of the brick – from the Sand Jet, to a full on Sand Blast, or even more aggressive high pressure water systems.
We specialise in using a listed building approved low pressure sand jetting system that has been used nationwide for property restoration. The system, in our trained hands, causes minimal damage to an underlying surface and is flexible enough to tackle most property restoration cleaning tasks. The picture on the right shows our first ‘area’ on the bricks of Hull Paragon Station – where decades of dirt were removed from this listed brickwork with the sand jet – this was part of the works to upgrade the station to Hull’s Transport Interchange – and we cleaned the bricks inside and out.
In recent years Conservation officers have become very keen on Stonehealth’s DOFF system – which is a superheated steam, low pressure, pressure washer. We have therefore invested in a Restorative Technique’s Thermatec machine- which does the same thing – just made by a different company. We have used this on multiple brick and stone projects since. It is very effective at dirt and grime removal – less so for paint removal – when it works it is very slow in comparison to the Sand Jet.
Painted Brick Cleaning
For external painted brick our sand jet system will almost certainly be our tool of choice – low dust and low damage (it is rare that repointing is necessary following our works). The system means that neighbours aren’t covered in abrasive (although some abrasive and paint debris is likely to end up downwind – nothing like the quantity that a traditional grit blast machine will generate) and paint is generally bound up in the damp sand and sloughs down the walls – to be scraped up at the end. This also means that metal contaminated paints (such as Lead based paints) can be cleaned without releasing the metals to the environment. There is a further advantage here in that the low consumption of the system means that metal contaminated waste is minimised. A full page on this website discussing painted brick cleaning can be found using this link.
As can be seen in the photo on the left, paint can be removed with the sand jet leaving the bricks and the pointing almost untouched – this makes the system suitable for working on sensitive surfaces such as listed buildings. This particular set of bricks were on a windmill in the centre of Goole (sad to say once all the paint was off, it was immediately replaced with new black paint!)
The farmhouse below was also listed – unpainted until the second world war – then painted by the Army to ‘disguise’ it! They also unfortunately used ‘paint, green, camouflage, for the use of’ and while the paint may have been suitable for painting lorries, tanks and armoured cars – it was less suitable for brickwork – and 70 years on the base coat of this paint was causing problems.
Traditional Dry Blasting of Brick
For internal works, and when there is no issue of lead based paints (for example) then we might recommend traditional dry sand blasting or gritblasting. By reducing the pressures and lowering consumptions we can nearly match the lack of damage that our sand jet causes – and at the same time not fill the property with water or wet sand. We have, for example, removed soot damage from plastered walls with a dry blast machines – a situation where the damp nature of the sand jet might have caused issues.
This particular building was being converted from a warehouse into a public house, in Cheshire some 10 years ago. We sandblasted the bricks, the concrete staircase, the iron columns that held the ceiling up, and I think the wooden beams.
Dry Ice Blasting
There are times when alternative methods are called for, one of which is Dry Ice blasting. Here a surface to be cleaned is blasted with solid CO2 particles, and the surface is cleaned through thermal shock, the massive volume change as dry ice particles turn into gas, and some abrasion of the surface contaminant, making the process ‘grit or sand free’.
The advantage of this system is that the ‘abrasive’ evaporates on impact, so the only ‘debris’ is the material being removed. It is nearly ‘dustless’ – about as dustless as it is possible to get for an open blast system – however it will still blow cobwebs, birds nests, paint debris etc. fairly liberally!
In this example on the left we were removing fire damage from a church tower.
An entire web page dedicated to Dry Ice Blasting is here
Environmentally Friendly Chemical Paint Stripping
Very occasionally a chemical stripper might be the correct option for removing paint. We specifically don’t use the high fume generating acetones or methylene chlorides of the past. The chemical we prefer is a specialist product previously imported from Canada where it had been developed by a company called Napier for environmentally friendly paint stripping of aircraft. For some reason this product can no longer be imported to Europe and a French company has started making their own version. This comes to us via a Southern Irish importer – and can take a while!
As can be seen with the pictures on the right, the challenge with all paint removal jobs is ‘what is beneath the paint’ with the test patch on the left – it was glazed tiles- with the patch on the right – more paint!
Pressure Washing, rapid environmentally friendly cleaning.
There are times when plain, cold water, pressure washing is an acceptable, environmentally friendly alternative. It is certainly cheaper and rapid, and can be quite effective for surface contaminants such as algae and grime. Subsequent cleaning with the sand jet can remove stubborn stains. It is our standard tool for new build brick cleaning. These cleaning techniques have been used effectively in projects in Lincoln and Derby.
This particular building was in Derbyshire, and I think had been previously Inland Revenue Offices, and not only did we was the walls down – but cleared the car park of moss and debris too.