High Pressure Water Blasting
A data sheet on our Pressurised Water cleaning services, a suitable summary for printing is available in PDF format, Pressure Washing Data Sheet
Greenleaf Contractors specialise in using a sand jetting system that has been used nationwide for property restoration, including gaining approval for and subsequently working on many Listed Buildings. 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 low pressure sand jet can clean surfaces without injecting large quantities of water into the surface, and with minimal surface damage, at the same time, the 'damp' system also captures dirt and abrasive, preventing the health and safety risks associated with sandblasting.
That being so, there are times when pressure washing is an acceptable alternative. It is certainly cheaper, and can be quite effective for surface contaminants such as algae and grime. Subsequent cleaning with the sand jet can remove stubborn stains. We own electric, petrol and diesel powered machines, and the big diesel machine will also generate high pressure hot water and steam. Our thermatec machine will generate DOFF type superheated steam at medium pressures. This particular tiled wall was inside an old fire station in Gipton, Leeds, West Yorkshire.
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We can also hire in (or purchase if your job is big enough!) bigger machines in the 'High Pressure Water Blasting' range of pressures - 200 to 500bar. These pressures will strip paint from surfaces - the only significant issue from a post cleaning point of view is that some paints require a key to the surface - and this isn't generated by water blasting - but we know a machine that couples the low pressure sand jet to the power of UHP water jetting to create a very aggressive and rapid clean.
Concrete Cleaning
This bridge was from central York, transported to a convenient airfield for cleaning and refurbishment.
High pressure water jetting (at around 500bar and 100 degrees centigrade) was used to strip the paint.
Metal Cleaning
High pressure water jetting is very effective at removing loose paint, and rust. Probably three times faster than using the sand jet.
This sample on a water tank near Driffield in East Yorkshire - left hand side sample high pressure water, right hand side sand jet. The Sand jet has scratched the surface, removed all the paint - but causes instant flash rusting. If the paint being used can cope with a water jet prepared surface (and some will require that scratch on the surface to be able to grab onto the metal) then high pressure water is faster, less messy, and doesn't involve coping with flash rusting. High pressure water is particularly good at removing flakes of rust scale.
This metal fence in Lincon was very rapidly taken back to primer with high pressure water.
Internal Glazed Tiles
This was the result of a test panel inside a Leeds Fire Station- cleaning the decades of grime from the glazed surfaces.
Listed Buildings - paint from render
We have now used high pressure water machines to strip paint from three rendered buildings, two in East Yorkshire, one in Nottingham - and two of them were Listed Grade II. A test panel is highly recommended as it is the quality and strength of the render is critical - some modern renders disappear in seconds under the onslaught of the water jet - and typically we can blow out render in fill and previous small scale repairs - and this is the reason why this isn't a method to use on brick surfaces - as the pointing will not survive it! But... this is a rapid and cost effective way to remove a lot of paint over a large area.
Key Benefits
- High Pressure Water cost effective compared to other techniques, but hire costs mean that there is a break even point where it will win over Sand jetting
- Our machines allow variable temperature and pressures - to allow flexibility.
- Keeping to the requirements of BS 8221-1&2 :2000 the British Standard Code of Practice for Cleaning and Surface repair of buildings.